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Eczema, or atopic dermatitis (AD), is a chronic inflammatory skin condition marked by skin barrier dysfunction and immune dysregulation. Driven by genetic, immunological and environmental factors, as well as skin microbiome changes, emerging research suggests live biotherapeutic products (LBPs) could revolutionise its treatment and prevention. What We Know: During AD flare-ups, microbial diversity declines and Staphylococcus aureus  often dominates. Up to 70% of individuals with AD have S. aureus  colonisation on lesional skin and 30%–40% on non-lesional skin. A disrupted skin barrier, due to genetic and environmental factors, increases pH and water loss, creating conditions for S. aureus overgrowth (Totté et al., 2016). The severity of AD symptoms correlates with S. aureus  levels, exacerbated by toxins like δ-toxin and PSMα. Notably, many AD patients’ microbiomes lack gram-negative bacteria, further reducing microbial diversity (Locker et al., 2024). LBPs, defined as live organisms used to prevent, treat, or cure diseases, offer a novel approach to addressing these imbalances (Ağagündüz et al., 2022). Industry Impact and Potential: LBPs show promise by targeting S. aureus  overgrowth and improving skin health. Examples include Roseomonas mucosa  and coagulase-negative staphylococci (e.g., Staphylococcus hominis  A9), which reduce S. aureus  through antimicrobial and immune-modulating mechanisms. Furthermore, Nitrosomonas eutropha  B244 produces anti-inflammatory nitrite, showing potential to alleviate AD  symptoms(Locker et al., 2024). @Concerto Bioscience recently initiated a Phase 1 trial of Ensemble No.2 (ENS-002), a topical LBP targeting S. aureus overgrowth. ENS-002 employs three microbial strains to address the root microbial deficiencies linked to AD. Designed for topical application, it minimises systemic risks like immune suppression or infections (Andrus, 2024). ENS-002’s development leveraged Concerto's kChip screening technology, which tests millions of microbial combinations to uncover interactions that modulate skin health. Using kChip, over 6 million microbial communities were screened to identify the "ensemble" of bacteria that neutralises pathogenic S. aureus. Our Solution: At Sequential, we specialise in Microbiome Product Testing to support your business’ goals, such as innovative AD treatments. Our tailored studies and product formulation support ensure developments that maintain microbiome integrity, promoting efficacy, compatibility, and healthier skin. Partner with us to confidently develop microbiome-based topical solutions that address AD’s unique challenges. References: Ağagündüz, D., Gençer Bingöl, F., Çelik, E., Cemali, Ö., Özenir, Ç., Özoğul, F. & Capasso, R. (2022) Recent developments in the probiotics as live biotherapeutic products (LBPs) as modulators of gut brain axis related neurological conditions. Journal of Translational Medicine. 20 (1), 460. doi:10.1186/s12967-022-03609-y. Andrus, E. (2024) Concerto Biosciences Announces First Participant Dosed with Live Biotherapeutic ENS-002 in Phase 1 Trial for Atopic Dermatitis. 2024. Concerto Biosciences. https://www.concertobio.com/press/concerto-biosciences-announces-first-participant-dosed-with-live-biotherapeutic-ens-002-in-phase-1-trial-for-atopic-dermatitis [Accessed: 19 November 2024]. Locker, J., Serrage, H.J., Ledder, R.G., Deshmukh, S., O’Neill, C.A. & McBain, A.J. (2024) Microbiological insights and dermatological applications of live biotherapeutic products. Journal of Applied Microbiology. 135 (8), lxae181. doi:10.1093/jambio/lxae181. Totté, J.E.E., van der Feltz, W.T., Hennekam, M., van Belkum, A., van Zuuren, E.J. & Pasmans, S.G.M.A. (2016) Prevalence and odds of Staphylococcus aureus carriage in atopic dermatitis: a systematic review and meta‐analysis. British Journal of Dermatology. 175 (4), 687–695. doi:10.1111/bjd.14566.

The ‘exposome’ refers to the complex interplay of environmental exposures that influence the skin over a lifetime, including factors such as pollution, UV radiation and lifestyle choices. Comparable in complexity to the skin microbiome, the exposome represents an exciting frontier in research, with significant implications for skincare innovation and personalised solutions. What We Know: The exposome encompasses a broad range of environmental and lifestyle factors: air pollution, UV radiation, climate, diet, sleep patterns, stress and hormonal changes. Each individual’s exposome is unique, shaped by the combination of these factors over time (Passeron et al., 2020). Key environmental elements such as traffic-related air pollution, hormones, nutrition, stress and sleep significantly impact skin ageing and overall skin health. For example, pollution accelerates pigmentation, wrinkles and eczema, while hormonal fluctuations, poor nutrition and stress contribute to inflammation, collagen degradation and conditions like atopic dermatitis, psoriasis and acne. These factors affect biochemical processes that influence skin ageing and the development of inflammatory skin disorders (Passeron et al., 2020). However, the skin’s exposome has been relatively underexplored and further investigation is needed to understand how these factors interact and the net effects they have on the skin (Krutmann et al., 2017). Industry Impact and Potential: As research into the exposome evolves, the skincare industry is increasingly focusing on how these factors drive skin ageing and health, leading to more personalised, targeted skincare solutions. One framework, called The Skin Interactome, integrates the genome, microbiome and exposome to unravel the molecular mechanisms underlying skin health and ageing (Khmaladze et al., 2020). This holistic approach examines how genetic, environmental and microbial factors work together to influence skin physiology. By identifying key molecular pathways, such as those involved in collagen synthesis, this framework aims to develop targeted strategies to protect skin health and delay the visible signs of ageing (Khmaladze et al., 2020). Pooling research across these distinct areas of skincare is vital, as it provides a comprehensive understanding of how environmental, lifestyle and biological factors collectively influence skin health and ageing. This integrated approach allows for the development of more targeted and effective skincare solutions. Our Solution: Sequential is at the forefront of microbiome research, supported by a database of 20,000 microbiome samples, 4,000 ingredients and a global network of 10,000 testing participants. Our customisable solutions span microbiome studies and product formulation, with a strong focus on preserving biome integrity. Whether exploring the skin, scalp, oral or vulvar microbiome, we are your ideal partner for advancing research. References: Khmaladze, I., Leonardi, M., Fabre, S., Messaraa, C. & Mavon, A. (2020) The Skin Interactome: A Holistic ‘Genome-Microbiome-Exposome’ Approach to Understand and Modulate Skin Health and Aging. Clinical, Cosmetic and Investigational Dermatology. 13, 1021–1040. doi:10.2147/CCID.S239367. Krutmann, J., Bouloc, A., Sore, G., Bernard, B.A. & Passeron, T. (2017) The skin aging exposome. Journal of Dermatological Science. 85 (3), 152–161. doi:10.1016/j.jdermsci.2016.09.015. Passeron, T., Krutmann, J., Andersen, M.L., Katta, R. & Zouboulis, C.C. (2020) Clinical and biological impact of the exposome on the skin. Journal of the European Academy of Dermatology and Venereology: JEADV. 34 Suppl 4, 4–25. doi:10.1111/jdv.16614.

Scalp psoriasis is a common yet often treatment-resistant autoimmune condition that frequently co-occurs with psoriasis in other areas. Currently, the specific influence of the scalp microbiome on scalp psoriasis, and how this can be leveraged for treatment, remains largely unexplored. What We Know: Psoriasis is a chronic inflammatory skin condition affecting 1–3% of the global population, characterised by persistent, scaly plaques. Genetic, environmental and epigenetic factors contribute to its development, with up to 80% of psoriasis patients experiencing scalp involvement (Choi et al., 2024).  Treatments for scalp psoriasis range from topical agents, including steroids and vitamin D analogues, to systemic treatments like methotrexate and cyclosporine. Despite available therapies, managing scalp psoriasis remains complex due to challenges with topical application and variability in patient response (Ghafoor et al., 2022) . Industry Impact and Potential: The skin microbiome of psoriasis patients differs significantly from that of healthy individuals. Psoriatic lesions exhibit increased Staphylococcus  and decreased Cutibacterium  compared to healthy controls. This dysbiosis may cause inflammation, impaired skin barrier functions and autoimmunity (Choi et al., 2024) . Researcher has shown that microbial diversity in the scalp microbiome increased with the severity of scalp psoriasis. Pseudomonas  and Malassezia  species, particularly M. globosa , were more prevalent in severe cases. Malassezia  is linked to several skin conditions, including psoriasis and its lipase activity may disrupt the skin barrier and provoke inflammation (Choi et al., 2024) .  Additionally, the IL-17 pathway, a key player in psoriasis pathogenesis, interacts with Malassezia  to exacerbate skin inflammation. Understanding these microbial changes offers a promising avenue for developing targeted treatments that address the root causes of scalp psoriasis, potentially enhancing patient outcomes (Choi et al., 2024) .  Powered by their Amino M³ Complex,™ @Act + Acre’s Microbiome Cooling Scalp Serum helps balance the scalp microbiome, soothing dryness, itching and reducing dandruff flakes. The formula uses peppermint oil for immediate relief, while amino acids, grape, ginger and frankincense restore microbiota balance and provide long-term protection against irritation. Our Solution: Sequential, with its database of over 20,000 microbiome samples and 4,000 ingredients, offers comprehensive services to evaluate product impacts on the microbiome. Our customizable microbiome studies, combined with real-world testing environments, provide critical insights into product efficacy. By partnering with Sequential, you gain access to data-driven solutions that help optimise your formulations and ensure they support scalp health in line with emerging research. References: Choi, J.-Y., Kim, H., Min, K.-H., Song, W.-H., Yu, D.-S., Lee, M. & Lee, Y.-B. (2024) Bacteria, Fungi, and Scalp Psoriasis: Understanding the Role of the Microbiome in Disease Severity. Journal of Clinical Medicine. 13 (16), 4846. doi:10.3390/jcm13164846. Ghafoor, R., Patil, A., Yamauchi, P., Weinberg, J., Kircik, L., Grabbe, S. & Goldust, M. (2022) Treatment of Scalp Psoriasis. Journal of drugs in dermatology: JDD. 21 (8), 833–837. doi:10.36849/JDD.6498.

Fasting, a practice rooted in history and religious traditions, has recently surged in popularity as a health trend. Its benefits - such as weight management, improved metabolic function and delayed ageing - are well-documented. However, new research suggests that fasting may also impact the oral microbiome, influencing oral health in unexpected ways. What We Know: Fasting involves abstaining from food, consuming only water or other approved liquids (e.g., herbal teas or black coffee) for an extended period of time. Different fasting types, such as intermittent fasting (less than 2 days) and long-term fasting (4 days to several weeks), have been studied clinically (Loumé et al., 2024). A lesser-known side effect of fasting is bad breath, or halitosis. This is often anecdotally linked to the "keto flu" during the body’s transition from burning carbohydrates to fat, but while ketone bodies may contribute to foul breath, this phenomenon differs from the pathological halitosis seen in some fasters (Loumé et al., 2024). Studies show that 80-90% of fasters with halitosis have oral microbiome dysbiosis. Oral microbes degrade residual proteins in saliva, food debris and shed epithelial cells, producing volatile sulphur compounds (VSCs) which are linked to halitosis, dysbiosis and periodontal disease (Loumé et al., 2024). Industry Impact and Potential: Recent research on long-term fasting’s effects on halitosis and the oral microbiome uncovered several key findings. Initially, fasting reduced microbial alpha diversity (a measure of species variety), but diversity rebounded and even exceeded baseline levels one and three months after fasting (Loumé et al., 2024). Fasting led to a decrease in genera such as Neisseria, Gemella  and Porphyromonas , while promoting an increase in others, including  Megasphaera, Dialister, Prevotella, Veillonella, Bifidobacteria, Leptotrichia, Selenomonas, Alloprevotella  and Atopobium . Firmicutes (Bacillota) became dominant during follow-up periods, while Proteobacteria  and Bacteroidetes  were suppressed (Loumé et al., 2024). The reduction in potentially harmful species like Porphyromonas  suggests a shift towards a less inflammatory microbial environment. Additionally, the correlation between microbial shifts and increased levels of dimethylsulfide - a compound linked to halitosis - indicates that fasting-induced changes in the microbiota may contribute to breath odour (Loumé et al., 2024). Our Solution: At Sequential, we are a trusted leader in microbiome product testing and formulation. Our customisable solutions empower businesses to innovate with confidence, ensuring the development of effective oral hygiene products that preserve the integrity of the oral microbiome. With our expertise, we help companies explore the potential of microbiome studies and product development not only for oral health but also for skin, scalp and vulvar microbiomes. References: Loumé, A., Grundler, F., Wilhelmi de Toledo, F., Giannopoulou, C. & Mesnage, R. (2024) Impact of Long-term Fasting on Breath Volatile Sulphur Compounds, Inflammatory Markers and Saliva Microbiota Composition. Oral Health & Preventive Dentistry. 22, 525–540. doi:10.3290/j.ohpd.b5795653.

Introduction: Cosmetic Preservatives Cosmetics are products designed to enhance or alter the appearance of the face, body, or hair, with effects such as hydration, anti-aging, whitening, and cleansing, depending on their intended purpose. Cosmetic formulations, consist of various ingredients that work together, including, base ingredients (water, surfactants, oils, polymers, emulsifiers) that provide texture and consistency, active ingredients such as hyaluronic acid for hydration or retinol for anti-aging, and colorants (natural or synthetic) that give pigmentation to the product (Tang & Du, 2024). Cosmetics are particularly water-based, and they can create a favorable environment for microbial growth. Therefore, “preservatives” are essential to prevent contamination of microbes and extend shelf life (Tang & Du, 2024). A well-designed preservation system, whether built into the formulation or added externally, should effectively prevent microbial contamination, maintaining product integrity from its sealed state until it is fully used, even after repeated exposure to air and contact (Halla et al ., 2018). Without preservatives, cosmetics could become breeding grounds for harmful bacteria and pose risks of infections or irritations, compromising both safety and effectiveness (Tang & Du, 2024). How do microorganisms contaminate cosmetics? Microbial contamination can occur at various stages, from production to consumer use, making it essential to identify and monitor all potential sources. Contamination during manufacturing (primary contamination) and during consumer handling (secondary contamination) can impact product safety and stability (Figure 1) (Halla et al ., 2018). To prevent microbial contamination in cosmetics, a comprehensive quality management system must be established, covering every stage from raw material selection to final consumer use. This includes strict quality control of raw materials, ensuring that only high-quality, contaminant-free ingredients enter the production process. Hygienic manufacturing processes, including proper cleaning, disinfection, and occupational hygiene, must be strictly followed to minimize the risk of primary contamination during production. Additionally, proper packaging and controlled distribution play a crucial role in preserving product integrity by preventing exposure to environmental contaminants (Uzdrowska & Górska-Ponikowska, 2023). Beyond manufacturing, consumer education on safe usage is equally important, as improper handling, such as using unclean applicators or exposing products to moisture, can introduce secondary contamination (Halla et al ., 2018).  Figure 1: Causes, effects, and prevention of cosmetic contamination. Image taken from   (Halla et al., 2018) . Microorganisms that have been identified in cosmetic products Cosmetic products can provide a favorable environment for microbial growth, particularly when produced under unsanitary conditions. Contamination often involves pathogenic bacteria such as Pseudomonas aeruginosa , Staphylococcus aureus , and Enterobacteria , which pose risks due to their ability to cause infections (Halla et al ., 2018).  Staphylococcus epidermidis  is another commonly detected microorganism linked to skin-related concerns (Alshehrei, 2023). Beyond bacterial contamination, fungal presence is a notable issue, especially Filamentous fungi , which are associated with opportunistic infections and mycotoxin production. Additionally, yeasts like Candida albicans  can proliferate in inadequately preserved formulations, increasing the likelihood of skin and mucosal infections (Halla et al ., 2018).  Although cases of infection from contaminated cosmetics are infrequent, studies have identified recurring microbial contaminants, including Klebsiella oxytoca , Burkholderia cepacia , Escherichia coli , Enterobacter gergoviae , and Serratia marcescens . While intact skin and mucous membranes serve as protective barriers, exposure to these pathogens may elevate infection risks, particularly for individuals with weakened immune systems or compromised skin integrity (Halla et al ., 2018). Regulations that have been placed for cosmetics As the cosmetic industry continues to evolve with the introduction of new ingredients, global regulations have been established to ensure consumer safety, product quality, and accountability for adverse reactions. Among the most influential regulatory frameworks are those from the United States, Japan, and the European Union, as these regions represent the largest cosmetic markets worldwide (Halla et al ., 2018).   United States Regulations In the United States, the Food and Drug Administration (FDA) oversees cosmetic safety and ensures that products entering the market comply with legal requirements. While the FDA does not mandate sterility in cosmetics, products must not contain pathogenic microorganisms, and the total microbial load must remain within safe limits. Although no strict microbial limits are specified by the FDA, the Personal Care Products Council (PCPC) provides industry guidelines, recommending that microbial contamination should not exceed 500 CFU/g for products intended for the eye area or infants and 1,000 CFU/g for all other cosmetics. Additionally, manufacturing facilities are expected to adhere to Good Manufacturing Practices (GMPs) to minimize the risk of microbial contamination (Table 1) (Halla et al ., 2018).       European Union Guidelines   In the European Union (EU), cosmetic safety is regulated under EU Council Directive 76/768/EEC. Microbiological safety guidelines are outlined by the Scientific Committee on Consumer Safety (SCCS), categorizing products into two groups:    Category 1: Products used on mucous membranes, eye area, or intended for children under three years old, where the microbial count must not exceed 100 CFU/g or CFU/mL (Halla et al ., 2018).       Category 2: All other cosmetic products, which must remain below 1,000 CFU/g or CFU/mL (Halla et al ., 2018).       Bacteria such as Pseudomonas aeruginosa , Staphylococcus aureus , and Candida albicans  are considered high-risk contaminants and must be absent in 1 g or 1 mL for Category 1 products and in 0.1 g or 0.1 mL for Category 2 products (Table 1) (Halla et al ., 2018).   Table 1: Regulations that have been placed for cosmetics. These regulations allow for strict quality control, hygiene practices, and microbial safety measures to be maintained in order to reduce contamination risks, ensuring the safety of cosmetic products for consumers. Preservation strategies in cosmetics   Cosmetic manufacturers use various strategies to prevent microbial contamination while maintaining product integrity. Preservation can be chemical, physical, or physicochemical, with two main stages:   1. Primary Preservation  - Implemented during manufacturing, focusing on Good Manufacturing Practices (GMP), including raw material quality control, water treatment, equipment sterilization, and hygienic environments (Halla et al ., 2018).   2. Secondary Preservation  - Applied after production to maintain stability during storage, transport, and consumer use. Different methods are used; Physical Preservation - Protective packaging, such as airless pumps, narrow openings, antimicrobial packaging, can minimise contamination (Halla et al ., 2018).     Physicochemical Preservation - Factors like water activity reduction (using salts, polyols, and hydrocolloids), emulsion type (W/O emulsions offer better protection than O/W), and pH control, that create an unfavorable environment for microbial growth (Halla et al ., 2018).     Chemical Preservation - Includes synthetic preservatives that are regulated under cosmetic laws, natural preservatives such as plant extracts and essential oils, and multifunctional ingredients such as, chelating agents, surfactants, and humectants that enhance microbial resistance while serving additional functions (Halla et al ., 2018).   The combination of these approaches, known as “Hurdle Technology”, ensures cosmetics remain safe, and free from pathogenic microorganisms (Halla et al ., 2018). The preservatives paradox Benefits of preservatives in cosmetics Preservatives play a crucial role in preventing the growth of bacteria, fungi, and other microorganisms, minimizing the risk of infections. Moreover, by maintaining product stability, preservatives help extend shelf life and ensure long-term safety for consumers. Preservatives also allow the development of diverse formulations, particularly those with high water content, which are more prone to microbial contamination (Tang & Du, 2024).  Challenges of preservatives in cosmetics Certain preservatives, such as parabens and isothiazolinones, have been associated with adverse health effects, including skin irritation, and to ensure effective preservation, certain formulas have high concentrations of preservatives, which further increase the risk of toxicity to consumers (Halla et al ., 2018).   Cosmetic preservatives are hazardous micropollutants that often remain in aquatic environments due to incomplete removal in wastewater treatment. These chemicals can harm organisms like fish and algae, raising concerns about their environmental impact (Nowak-Lange, Niedziałkowska & Lisowska 2022). Applying cosmetic products can disrupt the skin microbiota, affecting the balance of the skin, mucous membranes, and scalp. Products like moisturizers, soaps, shampoos, and lotions may alter the skin’s protective lipid layer and impact its natural microflora. This imbalance can result from factors such as preservatives, which remain active after application and interact with microbes, disturbing the bacterial balance (Pinto et al ., 2021). Preservatives impact on the skin microbiome Preservatives can impact the skin microbiome in several ways, and some of which are; Disruption of microbiota Certain preservatives can disrupt the microbiome balance of the skin. A study highlights that skincare products, particularly those with preservatives, influence the skin microbiome. The study found that preservative-free products (PFPs) led to an increase in commensal bacteria such as Sphingomonas   and   Neisseria , which are associated with UV protection, anti-aging effects, and reduced skin inflammation. In contrast, conventional skincare products (CSPs), which typically contain preservatives, showed different microbial shifts and were linked to a less pronounced positive impact on skin microbiome composition.(Wagner et al ., 2024). Disruption of microbial communication Some preservatives may interfere with quorum sensing, which is a way bacteria communicate using signaling molecules to coordinate group behaviors based on population density. Quorum sensing helps regulate functions like enzyme production, biofilm formation, and virulence (Falà et al ., 2022). By disrupting this process, preservatives can inhibit these functions and disrupt the microbial balance.  Alteration of skin pH Certain preservatives can alter the skin's pH, thereby influencing the growth of microorganisms. Maintaining the right pH is crucial for a healthy microbiome, as skincare products directly interact with both skin pH and microbial communities (Janssens-Böcker et al ., 2025).   Barrier function impact Some preservatives such as parabens and formaldehyde releasers, can weaken the skin barrier over time. Exposure to such ingredients may lead to barrier disruption, reducing the skin’s ability to retain moisture, defend against irritants, and maintain homeostasis, potentially causing sensitivity and irritation (Panwar & Rathore, 2024). Comprehensive review: Preservatives & the skin microbiome To gain a deeper understanding of the current knowledge on the impact of preservatives on the skin microbiome, two well-established publications have been selected. Study 1: Effect of commonly used cosmetic preservatives on skin resident microflora dynamics (Pinto et al ., 2021) The study investigated the effects of commonly used cosmetic preservatives (Table 2) on the skin microbiota using  in vitro methods. Methodology Table 2: List of formulations [C1-C12] containing preservatives used in this work. Table taken from (Pinto et al., 2021) . A solution was prepared by combining preservatives at standard concentrations with water and Aristoflex AVC (a gelling agent) to achieve a consistent viscosity. To mimic real skin conditions, a Labskin 3D skin model was utilized, enabling the researchers to observe interactions between the preservatives and the bacterial strains. The bacterial strains studied included Cutibacterium acnes , Staphylococcus epidermidis , and Staphylococcus aureus , which are key skin microbes. These strains were cultured under controlled conditions before being introduced to the 3D skin model.  Following bacterial inoculation, different preservative combinations were applied to the skin models to assess their impact on the skin microbiome. A preservative free gel was used as a control to determine baseline bacterial activity. After 3 hours of contact, two 4mm biopsy samples were collected from each skin model. RNA was extracted from the skin biopsies, and gene expression levels were analyzed using quantitative real-time PCR (qRT-PCR). Results  The results indicate that different preservative combinations have varying effects on skin microbiota (Table 3). Some combinations, such as C2 and C3, strongly inhibit S. aureus while moderately inhibiting C. acnes  without affecting S. epidermidis , making them ideal for restoring microbiome balance. Others, like C1, C4, C6, and C7, moderately inhibited S. aureus  and slightly inhibited C. acnes  while preserving S. epidermidis , suggesting their suitability for maintaining a balanced skin microbiome.   In contrast, combinations like C5, C8, and C9 significantly reduced S. epidermidis , which could disrupt the natural microbiota, making them less ideal for general cosmetic use. Notably, C10 strongly inhibited S. aureus  but had minimal impact on C. acnes  and S. epidermidis , making it a potential choice for targeting S. aureus driven dysbiosis. Table 3: Activity of the different combination of preservatives tested on growth dynamic expressed as % of inhibition. +++, strongly inhibited [< 75%]; ++, moderately inhibited [90–80%]; +, weakly inhibited [98–91%]; −, no inhibition. Table taken from (Pinto et al., 2021) . Conclusion In conclusion, the study shows that different preservative combinations have varying effects on the skin’s microbiome. Hence, choosing the right preservatives in cosmetics is important to keep the skin microbiome healthy and balanced.  There are several limitations of the study. The study only focuses on three bacterial strains Staphylococcus aureus , Staphylococcus epidermidis , and Cutibacterium acnes  which limits its ability to fully represent the diverse and complex skin microbiome. It does not account for the realistic effects of product usage or the dynamic interactions within the skin’s ecosystem. Additionally, the study does not reflect the full functionality of the skin, including its ability to regulate microbial balance. Importantly, it overlooks the microbiome’s natural resilience.  However, the findings provide valuable insights for formulators when having to choose preservatives for cosmetic products. Study 2: In-vivo  impact of common cosmetic preservative systems in full formulation on the skin microbiome (Murphy et al ., 2021) The study investigated the in vivo  impact of common cosmetic preservatives (Table 4) on the skin microbiome. Methodology Table 4: Ingredients of the 4 different formulations. In bold are the preservatives compositions. Table taken from (Murphy et al., 2021) . The study involved 60 healthy adult female participants aged between 18–55 from different ethnicities. 4 products were tested (3 rinse-off and 1 leave-on products), and each product was tested on a group of 15 participants, with no pre-conditioning phase to maintain their natural skin microbiome.  Leg skin microbiome samples were collected from each subject before and after application of the products, and the impact of the preservatives containing products was analyzed by using standard microbiome analysis including taxonomic and diversity analysis. Results: Alpha Diversity Alpha diversity analysis was performed to evaluate the preservatives impact on the  leg skin microbiome before and after product application, by using three common metrics, Chao1, Faith’s Phylogenetic Distance, and Shannon Entropy. All samples were standardized to a read count of 8000 based on rarefaction curve analysis.  Figure 2: Alpha diversity analysis of leg skin microbiome before and after product application. (A) Per sample alpha diversity assessment of the impact of the different preservation systems on the skin microbiome, (B) Group alpha diversity assessment of the impact of the different preservation systems on the skin microbiome, (C) Statistical analysis of alpha diversity changes between timepoints for each preservation system. Image taken from (Murphy et al., 2021) . As shown above (Figures, (A) Alpha diversity per sample for different preservation systems, (B) Group alpha diversity for preservation systems, (C) Statistical analysis of alpha diversity changes over time for each system), no significant changes in alpha diversity were observed after using the products. Results: Beta Diversity Beta diversity analysis was performed to evaluate the potential changes in the microbiome community structure across all product groups. The Bray-Curtis and Jaccard metrics were used to identify any significant shifts in the community after product use (Figures 3A–3D). No significant changes were observed. Fig 3. Beta diversity analysis of leg skin microbiome before and after formulation application. Analysis of the impact of cosmetic products containing different preservation systems (A-D) using Bray Curtis and Jaccard Diversity metrics. Panels A-D correspond to preservation systems A-D. Image taken from (Murphy et al., 2021) . Conclusion The study had several limitations. One being, the product's effectiveness diminishes due to dilution, particularly in wash-off products. Moreover, the study was limited to the leg skin microbiome, and does not apply to other body areas with different microbial compositions. Additionally, the study only focused on short-term effects, leaving the long-term impacts of continuous product use unclear. Finally, not including a preservative-free control group, limited the ability to fully assess the preservatives impact on the skin microbiome. However, despite these limitations the study was able to show us that the preservative containing products had no significant changes in the skin microbiome’s structure or diversity after usage. These data suggest that the different preservation systems in full formulation have minimal impact on the skin microbiome. The analysis also shows that the leg skin microbiome can recover to its original state after using the products. This was true for both wash-off products, which are diluted during use, and leave-on lotions, where the product stays on the skin longer without dilution.  In summary, preservatives are essential for ensuring cosmetic safety and stability, and both the in vitro and in vivo studies highlight the importance of selecting appropriate preservatives, and that when used in full formulation it has only minimal effects on the skin microbiome. However, more future research needs to be done to deepen our understanding of their influence on skin microbiome and health. References Alshehrei F. M. (2023). Isolation and Identification of Microorganisms associated with  high-quality and low-quality cosmetics from different brands in Mecca region -Saudi Arabia. Saudi journal of biological sciences , 30 (12), 103852. https://doi.org/10.1016/j.sjbs.2023.103852 Falà, A. K., Álvarez-Ordóñez, A., Filloux, A., Gahan, C. G. M., & Cotter, P. D. (2022).  Quorum sensing in human gut and food microbiomes: Significance and potential for therapeutic targeting. Frontiers in microbiology , 13 , 1002185. https://doi.org/10.3389/fmicb.2022.1002185 Halla, N., Fernandes, I. P., Heleno, S. A., Costa, P., Boucherit-Otmani, Z., Boucherit, K.,  Rodrigues, A. E., Ferreira, I. C. F. R., & Barreiro, M. F. (2018). Cosmetics Preservation: A Review on Present Strategies. Molecules (Basel, Switzerland) , 23 (7), 1571. https://doi.org/10.3390/molecules23071571 Janssens-Böcker, C., Doberenz, C., Monteiro, M., & de Oliveira Ferreira, M. (2025).  Influence of Cosmetic Skincare Products with pH < 5 on the Skin Microbiome: A Randomized Clinical Evaluation. Dermatology and therapy , 15 (1), 141–159. https://doi.org/10.1007/s13555-024-01321-x Murphy, B., Hoptroff, M., Arnold, D., Eccles, R., & Campbell-Lee, S. (2021). In-vivo impact of  common cosmetic preservative systems in full formulation on the skin microbiome. PloS one , 16 (7), e0254172. https://doi.org/10.1371/journal.pone.0254172 Nowak-Lange, M., Niedziałkowska, K., & Lisowska, K. (2022). Cosmetic Preservatives:  Hazardous Micropollutants in Need of Greater Attention? International Journal of Molecular Sciences , 23 (22), 14495. https://doi.org/10.3390/ijms232214495 Panwar, Aakash & Rathore, Priyanka. (2024). Impact of formulation excipients on skin  barrier functions: A review. International Journal of Pharmaceutical Chemistry and Analysis. 11. 41-44. 10.18231/j.ijpca.2024.005.  Pinto, D., Ciardiello, T., Franzoni, M., Pasini, F., Giuliani, G., & Rinaldi, F. (2021). Effect of  commonly used cosmetic preservatives on skin resident microflora dynamics. Scientific reports , 11 (1), 8695. https://doi.org/10.1038/s41598-021-88072-3 Tang, Zhenyu & Du, Qiaoyan. (2024). Mechanism of Action of Preservatives in Cosmetics.  Journal of Dermatologic Science and Cosmetic Technology. 1. 100054. 10.1016/j.jdsct.2024.100054.  Uzdrowska, Katarzyna & Górska-Ponikowska, Magdalena. (2023). Preservatives in  cosmetics technology. Aesthetic Cosmetology and Medicine. 12. 73-78. 10.52336/acm.2023.008.  Wagner, N., Valeriano, V. D., Diou-Hirtz, S., Björninen, E., Åkerström, U., Engstrand, L.,  Schuppe-Koistinen, I., & Gillbro, J. M. (2024). Microbial Dynamics: Assessing Skincare Regimens’ Impact on the Facial Skin Microbiome and Skin Health Parameters. Microorganisms , 12 (12), 2655. https://doi.org/10.3390/microorganisms12122655

Numerous deodorants and antiperspirant products have been developed to combat and treat malodour or body odour (BO). New approaches target the axillary (underarm) microbiome, the cause of BO, and meadowfoam extract could offer a natural solution. What We Know: Sweat is initially odourless and axillary malodor only develops when the cutaneous microbiome enzymatically breaks down sweat molecules produced by apocrine sweat glands. Certain molecules responsible for the odour associated with sweat have been identified, including an apical efflux pump encoded by the ABCC11  (MRP8) gene (Martin et al., 2010). Bacterium Staphylococcus hominis  has been identified as one bacterium that produces malodorous thiol compounds through the enzymatic degradation of sweat. The enzyme C-S lyase breaks down Cys-Gly-3M3SH, a peptide derivative found in sweat, into constituents including 3M3SH, which is a highly malodorous volatile compound from the thiol family. Due to its thiol nature, 3M3SH has a much lower olfactory threshold than other volatile compounds, making it the primary contributor to the intensity of perspiration odours (Verzeaux et al., 2024). White meadowfoam, Limnanthes alba , is a species of flowering plant native to California and Oregon that is known for its use in cosmetics and hair care products due to its stability, smooth texture and long-lasting presence on the skin (AgMRC, 2023).    Industry Impact and Potential: A deodorant containing meadowfoam extract was shown to be effective in reducing S. hominis. This product significantly reduced  S. hominis  abundance and C-S lyase activity, effectively decreasing odour without disrupting the axillary microbiome balance (Verzeaux et al., 2024). Traditional odour control methods - preventing sweat, masking odours with fragrance, or using antiseptic agents - face criticism due to physiological concerns, potential skin irritation, disruption of the axillary microbiota and the use of controversial ingredients like aluminium salts and alcohol. These issues highlight the need for risk-free, natural solutions that specifically target the biological mechanisms behind malodour production (Verzeaux et al., 2024).   Therefore, researchers propose meadowfoam-containing deodorants as a promising natural alternative for managing BO, with participants reporting high satisfaction in controlling both odour and perspiration (Verzeaux et al., 2024). Our Solution: Sequential is a leading expert in comprehensive, end-to-end microbiome product testing and formulation. Our specialised, customisable services enable businesses to develop innovative products that support and maintain microbiome health, ensuring both effectiveness and compatibility. We offer tailored expertise in facial, oral, scalp and vaginal microbiome research and formulation, providing full support for your product development needs, which may be extended to products targeting the axillary microbiome. References: Martin, A., Saathoff, M., Kuhn, F., Max, H., Terstegen, L. & Natsch, A. (2010) A Functional ABCC11 Allele Is Essential in the Biochemical Formation of Human Axillary Odor. Journal of Investigative Dermatology. 130 (2), 529–540. doi:10.1038/jid.2009.254. Verzeaux, L., Lopez-Ramirez, N., Grimaldi, C., Guedj, O., Aymard, E., Muchico, H. & Closs, B. (2024) Meadowfoam to Control S. Hominis and Axillary Malodor – As Shown by Meta Sequencing and Culturomics. Cosmetics & Toiletries. https://www.cosmeticsandtoiletries.com/cosmetic-ingredients/actives/article/22916729/silab-meadowfoam-to-control-s-hominis-and-axillary-malodor-as-shown-by-meta-sequencing-and-culturomics .

Vaginal seeding involves using a cotton gauze or swab to collect vaginal fluids and transfer them to a newborn's mouth, nose, or skin. This practice is typically done after cesarean deliveries, where the baby doesn’t naturally come into contact with the mother’s vaginal bacteria. The goal of vaginal seeding is to introduce maternal vaginal bacteria to the infant, with the idea that it may promote proper gut colonization and potentially reduce the risk of conditions like asthma, allergies, and immune disorders, which have been linked to rising cesarean delivery rates. What we know: A study found that 30 cesarean-born infants who underwent vaginal seeding had fecal and skin microbiota that more closely resembled those of vaginally born infants during their first year (Kelly, Nolan & Good, 2021). Infant microbiota showed more variability compared to maternal microbiota, with cesarean-born infants having the highest variability, vaginal-born infants the lowest, and vaginally seeded infants displaying intermediate variability in their fecal, oral, and skin samples (Kelly, Nolan & Good, 2021). Research on vaginal microbiota transfer (VMT) through exposure to maternal vaginal fluids revealed that this process significantly accelerated the maturation of gut microbiota in newborns (Zhou et al ., 2023). They also demonstrated that VMT regulated levels of certain fecal metabolites and metabolic functions, including carbohydrate, energy, and amino acid metabolism, within 42 days after birth (Zhou et al ., 2023). VMT also can influence infant neurodevelopment by enhancing various metabolites (Zhou et al ., 2023).   Industry impact & potential: While vaginal seeding shows potential, its long-term effects on health outcomes still needs to be investigated. VMT may influence infant neurodevelopment by enhancing various metabolites; however, the precise mechanisms behind this effect need further investigation for clarification (Zhou et al ., 2023). Our solution: At Sequential, we conduct research on the vaginal microbiome to understand its role in women's health. Our efforts center around leveraging cutting-edge sequencing technologies to thoroughly analyze microbial communities. By characterizing these communities, we aim to identify specific biomarkers that can indicate health conditions or risks. This research not only enhances our understanding of the vaginal microbiome's role in overall well-being but also aids in developing targeted solutions for maintaining vaginal health.  Reference: Committee Opinion No. 725: Vaginal Seeding. Obstet Gynecol. 2017 Nov;130(5):e274-e278.  doi: 10.1097/AOG.0000000000002402. PMID: 29064974. Kelly JC, Nolan LS, Good M. Vaginal seeding after cesarean birth: Can we build a better  infant microbiome? Med. 2021 Aug 13;2(8):889-891. doi: 10.1016/j.medj.2021.07.003. PMID: 35590163. ​​Zhou L, Qiu W, Wang J, Zhao A, Zhou C, Sun T, Xiong Z, Cao P, Shen W, Chen J, Lai X,  Zhao LH, Wu Y, Li M, Qiu F, Yu Y, Xu ZZ, Zhou H, Jia W, Liao Y, Retnakaran R, Krewski D, Wen SW, Clemente JC, Chen T, Xie RH, He Y. Effects of vaginal microbiota transfer on the neurodevelopment and microbiome of cesarean-born infants: A blinded randomized controlled trial. Cell Host Microbe. 2023 Jul 12;31(7):1232-1247.e5. doi: 10.1016/j.chom.2023.05.022. Epub 2023 Jun 15. PMID: 37327780.

Cutaneous T-cell lymphoma (CTCL) is a type of cancer that grow primarily in the skin. The most common forms are Mycosis fungoides (MF) and Sézary syndrome (SS). MF usually appears as red patches, plaques, or tumors on the skin, progressing slowly, while SS is more aggressive, with widespread redness and swollen lymph nodes. CTCL weakens the immune system, leading to frequent infections, chronic inflammation, and reduced ability to fight tumors (Dey et al ., 2024). In Europe and the USA, CTCL affects around 0.55 to 1.06 per 100,000 people, with MF being the most common form (Łyko & Jankowska-Konsur, 2022).  What we know: External factors, such as microbial antigens, may worsen the disease by promoting chronic inflammation and cancerous cell transformation (Dey et al ., 2024). Staphylococcus aureus  and Staphylococcus epidermidis , plays a key role in CTCL (Jost & Wehkamp, 2022). Staphylococcus aureus  contribute to morbidity and mortality by producing enterotoxins that disrupt skin barriers, activate T-cells, and promote cancer progression. In contrast, Staphylococcus epidermidis supports skin barrier function and modulates immune responses through the production of lantibiotics (Jost & Wehkamp, 2022). In CTCL patients, shifts in the abundance of bacteria such as Corynebacterium  and Cutibacterium (Jost & Wehkamp, 2022). Enterococcus  has been found in necrotic tumors of MF patients and successfully treated with antibiotics, while Pseudomonas aeruginosa , often fatal in septic CTCL cases, contributes to over half of the deaths (Jost & Wehkamp, 2022). Staphylococcus aureus  strains were prevalent and showed significant resistance to common antibiotics, complicating treatment with standard therapies (Licht et al ., 2024). Industry impact & potential: 3D human skin culture models could improve our understanding of the interactions between Staphylococcus aureus , immune cells, and malignant cells, while also examining how environmental factors affect skin microbiota, potentially identifying biomarkers or therapeutic targets (Jost & Wehkamp, 2022). Research on the impact of treatment on the skin microbiome in CTCL is still needed, and further studies on non-antibiotic treatments that restore microbiome balance could improve CTCL management (Łyko & Jankowska-Konsur, 2022). Our solution: Sequential specializes in skin microbiome analysis and in vivo formulation testing, providing scientifically-backed solutions to improve skin health through microbiome modulation. We ensure your product meets industry standards and delivers optimal skincare quality. Reference: Dey S, Vieyra-Garcia PA, Joshi AA, Trajanoski S, Wolf P. Modulation of the skin microbiome  in cutaneous T-cell lymphoma delays tumour growth and increases survival in the murine EL4 model. Front Immunol. 2024 Apr 5;15:1255859. doi: 10.3389/fimmu.2024.1255859. PMID: 38646524; PMCID: PMC11026597. Jost M, Wehkamp U. The Skin Microbiome and Influencing Elements in Cutaneous T-Cell  Lymphomas. Cancers (Basel). 2022 Mar 4;14(5):1324. doi: 10.3390/cancers14051324. PMID: 35267632; PMCID: PMC8909499. Licht, P., Dominelli, N., Kleemann, J. et al.  The skin microbiome stratifies patients with  cutaneous T cell lymphoma and determines event-free survival. npj Biofilms Microbiomes 10, 74 (2024). https://doi.org/10.1038/s41522-024-00542-4 Łyko M, Jankowska-Konsur A. The Skin Microbiome in Cutaneous T-Cell Lymphomas  (CTCL)-A Narrative Review. Pathogens. 2022 Aug 18;11(8):935. doi: 10.3390/pathogens11080935. PMID: 36015055; PMCID: PMC9414712.

The menstrual cycle is a recurring process, usually lasting about 28 days. It has four key phases: menstrual, follicular, ovulation, and luteal, each regulated by hormonal changes. These hormonal shifts not only impact reproductive functions but also influence various aspects of a woman's health, including the composition and balance of the vaginal microbiota, which can fluctuate throughout the cycle. What we know: Lactobacillus  species are among the most common colonizers of the vaginal tract in women of reproductive age and are recognized as key components of a healthy vaginal microbiome (Krog et al ., 2022). Lactobacillus  is thought to defend against infections and maintain a healthy vaginal epithelium by producing lactic acid, which lowers the vaginal pH and makes it difficult for pathogenic bacteria to grow (Song et al ., 2020). Menstrual blood neutralizes the acidic vaginal environment, raising the pH, which promotes the growth of anaerobic bacteria like Streptococcus  and Gardnerella , while reducing Lactobacillus  populations, and the iron in menstrual blood also nourishes certain bacteria (Shen et al ., 2022). Women with unstable Vaginal Community Dynamics (VCDs) showed higher phage counts, often dominated by Lactobacillus iners , and had Gardnerella spp  strains more likely to carry bacteriocin-coding genes (Hugerth et al ., 2024). Menstruation triggers an inflammatory response characterized by increased cytokine production and a higher accumulation of mature, activated neutrophils in the vagina, alongside an increase in Streptococcaceae  (Adapen et al ., 2022). Industry impact & potential: Modifying the vaginal microbiota with antibiotics or probiotics could be beneficial , and recognizing effective therapeutic strategies for these modifications is important (Adapen et al ., 2022). Our solution: At Sequential, we have assembled a dedicated team of scientists who have meticulously studied the human microbiome including the vaginal microbiome. With experience collaborating with many clients worldwide, we are well-prepared to partner with your company on intimate female health applications, microbiome testing, in vivo  and clinical certification, and formulation support. Reference: Adapen C, Réot L, Nunez N, Cannou C, Marlin R, Lemaître J, d'Agata L, Gilson E, Ginoux  E, Le Grand R, Nugeyre MT, Menu E. Local Innate Markers and Vaginal Microbiota Composition Are Influenced by Hormonal Cycle Phases. Front Immunol. 2022 Mar 25;13:841723. doi: 10.3389/fimmu.2022.841723. PMID: 35401577; PMCID: PMC8990777. Hugerth, L.W., Krog, M.C., Vomstein, K. et al.  Defining Vaginal Community Dynamics: daily  microbiome transitions, the role of menstruation, bacteriophages, and bacterial genes. Microbiome  12, 153 (2024). https://doi.org/10.1186/s40168-024-01870-5 Krog MC, Hugerth LW, Fransson E, Bashir Z, Nyboe Andersen A, Edfeldt G, Engstrand L,  Schuppe-Koistinen I, Nielsen HS. The healthy female microbiome across body sites: effect of hormonal contraceptives and the menstrual cycle. Hum Reprod. 2022 Jun 30;37(7):1525-1543. doi: 10.1093/humrep/deac094. PMID: 35553675; PMCID: PMC9247429. Shen L, Zhang W, Yuan Y, Zhu W, Shang A. Vaginal microecological characteristics of  women in different physiological and pathological period. Front Cell Infect Microbiol. 2022 Jul 22;12:959793. doi: 10.3389/fcimb.2022.959793. PMID: 35937699; PMCID: PMC9354832. Song SD, Acharya KD, Zhu JE, Deveney CM, Walther-Antonio MRSTetel MJ, Chia N 2020.  Daily Vaginal Microbiota Fluctuations Associated with Natural Hormonal Cycle, Contraceptives, Diet, and Exercise. mSphere5:10.1128/msphere.00593-20. https://doi.org/10.1128/msphere.00593-20

Diabetes mellitus is a recognised risk factor for the development of periodontitis, a gum disease that is characterised by the damage of the soft tissue surrounding the teeth. While the connection between diabetes and oral health is well-documented, targeted research on the oral microbiome in diabetes patients has historically been limited.  What We Know: The interplay between diabetes and periodontitis is bidirectional: poorly managed diabetes results in elevated blood sugar (glucose) levels in oral fluids, promoting the growth of bacteria that can lead to gum disease. Conversely, untreated periodontal infections can raise blood sugar levels, complicating diabetes management (Xiao et al., 2017) . Diabetes also alters the composition of oral bacteria. Studies involving the transfer of oral microbiota from diabetic mice to germ-free mice demonstrate that the microbiota from diabetic mice is more pathogenic. These diabetic mice exhibited increased levels of bacteria such as Proteobacteria (Enterobacteriaceae) and  Firmicutes (Enterococcus, Staphylococcus and  Aerococcus)  which are all associated with periodontitis and impaired healing in diabetic conditions (Xiao et al., 2017) . Industry Impact and Potential: IL-17 is a versatile cytokine involved in both immune defence and pathological immune responses. Elevated levels of IL-17 are observed in chronic periodontitis, where it triggers the production of pro-inflammatory mediators like IL-6 and RANKL, potentially leading to increased osteoclastogenesis, which contributes to bone loss (Xiao et al., 2016) . Research has shown that treatment with IL-17 antibodies can reduce the pathogenicity of the oral microbiome in diabetic mice. When the oral microbiota from IL-17-treated diabetic mice was transferred to germ-free mice, the recipients showed lower levels of neutrophil recruitment, decreased inflammatory markers like IL-6 and RANKL, and reduced bone resorption. This suggests that IL-17 treatment may mitigate the harmful effects associated with the oral microbiota in diabetes (Xiao et al., 2017) . @Frezyderm offers a specially designed oral care range for diabetics, utilising the combination of bioactive peptides and hyaluronic acid in their products. This formulation aims to regulate glucose levels in the mouth, while also reducing bone loss, combating dental plaque, hydrating and healing the gums, as well as preventing cavity formation.  Our Solution: At Sequential, we specialise in microbiome analysis and product development across the oral, skin, scalp and vaginal areas, pioneering innovative solutions that support and preserve the microbiome. With our extensive expertise, we are well-equipped to collaborate with your company in developing products that promote a healthy oral microbiome and overall oral health, for example, protecting against diabetes-associated dysbiosis.  References: Xiao, E., Mattos, M., Vieira, G.H.A., Chen, S., Corrêa, J.D., Wu, Y., Albiero, M.L., Bittinger, K. & Graves, D.T. (2017) Diabetes Enhances IL-17 Expression and Alters the Oral Microbiome to Increase Its Pathogenicity. Cell Host & Microbe. 22 (1), 120-128.e4. doi:10.1016/j.chom.2017.06.014. Xiao, W., Li, S., Pacios, S., Wang, Y. & Graves, D.T. (2016) Bone Remodeling Under Pathological Conditions. Frontiers of Oral Biology. 18, 17–27. doi:10.1159/000351896.

Hair and scalp oiling, a traditional Ayurvedic practice with ancient roots, is revered for its holistic health benefits. Today, this ritual is gaining popularity in modern, westernised cosmetic routines, particularly with coconut oil (CO), and emerging research is exploring its potential to influence the scalp microbiome. What We Know: Traditional hair oiling involves applying specific oils, often warmed, to the scalp and hair roots, followed by massage and leaving the oil to penetrate for several hours or days before washing. While CO, derived from Cocos nucifera , is especially popular, other oils like almond, castor, argan, olive, fenugreek, sesame, flaxseed and mustard have also been historically used (Mysore & Arghya, 2022) . The chemical composition of CO includes saturated fatty acids, making it a rich source of medium-chain fatty acids, with major components like myristic acid, capric acid, lauric acid and monolaurin. It also contains phenolic acids and antioxidants, such as tocopherol (Mysore & Arghya, 2022) . CO is prized for its cleansing, protective and restorative properties in haircare. It functions as a saponification agent in shampoos and has antibacterial and antifungal benefits against Cutibacterium acnes  and Staphylococcus aureus  due to its monolaurin content. Acting as an emollient, CO seals the hair cuticle and locks in moisture. Additionally, its low molecular weight and linear chain structure enable it to penetrate the hair shaft, aiding in the prevention of protein loss  (Mysore & Arghya, 2022) . Industry Impact and Potential: A longitudinal study of the scalp microbiome showed that CO may positively influence the scalp microbiome. CO application to the scalp increased beneficial bacteria like C. acnes  and fungi like Malassezia globosa , both of which are linked to healthier scalp conditions and reduced dandruff symptoms. The study also found that CO enriches bacterial pathways related to scalp health, such as biotin metabolism, while decreasing fungal pathogenesis pathway (Saxena et al., 2021) . Various hair care brands have developed scalp oiling products that incorporate CO. However, further research into how products like these may be optimised to benefit the scalp microbiome is largely unexplored and may offer a promising avenue of untapped research and commercial development in the cosmetics industry. Our Solution: With an extensive database comprising over 20,000 microbiome samples and 4,000 ingredients, alongside a global network of more than 10,000 testing participants, Sequential delivers thorough services for assessing product impacts and formulations. Our dedication to creating products that maintain microbiome integrity make us the ideal partner for your scalp and hair care product development needs, including the exploration of oil-based products. References: Mysore, V. & Arghya, A. (2022) Hair Oils: Indigenous Knowledge Revisited. International Journal of Trichology . 14 (3), 84–90. doi:10.4103/ijt.ijt_189_20. Saxena, R., Mittal, P., Clavaud, C., Dhakan, D.B., Roy, N., Breton, L., Misra, N. & Sharma, V.K. (2021) Longitudinal study of the scalp microbiome suggests coconut oil to enrich healthy scalp commensals. Scientific Reports . 11 (1), 7220. doi:10.1038/s41598-021-86454-1.

Skin microbiome transplantation is an emerging therapeutic approach designed to restore a healthy balance of microbial communities on the skin, especially in relation to various dermatological conditions. Recent research has underscored the crucial role of the skin microbiome in maintaining skin health and its contribution to the development of skin diseases like atopic dermatitis, psoriasis, and acne vulgaris. By transplanting healthy skin microbiota, it may be possible to reverse dysbiosis in microbial populations that can trigger inflammatory skin conditions. What we know: Transplantation can involve transferring whole skin microbiota from a healthy individual or using an artificial mixture of selected microorganisms (Junca et al ., 2022). The transplantation method is influenced by the interplay between donor microbiome composition, recipient microbiome composition, and transplant load, with certain combinations enhancing engraftment (Boxberger et al ., 2021). Studies have shown that transferring entire skin microbiomes between different body sites can replicate specific microbial effects, such as odour-causing bacteria could be transferred from the armpit to the forearm (Callewaert et al ., 2021). Transfer of microbiome swabs from the arm to the upper back, found greater diversity in the inner elbow compared to the back. Four arm-specific species persisted on the back after 24 hours, mainly from Gardnerella , Brachybacterium , and Actinomyces  (Callewaert et al ., 2021). In a clinical study, siblings were enrolled, including one with strong body odour. The skin microbiome from the non-odorous sibling was successfully transferred, resulting in reduced body odour and a new microbial balance with more staphylococci  and fewer corynebacteria  (Callewaert et al ., 2021). Industry impact & potential: Transferring live microorganisms from healthy donors to patients poses risks, necessitating pathogen screening standards (Junca et al ., 2022). Standardization of microbiome collection, preparation, and storage methods is essential for assessing transplantation efficacy (Junca et al ., 2022). Understanding microbiome interactions and pathofunctions will support personalized therapeutic strategies targeting specific skin microbiota functions (Junca et al ., 2022). Our solution: Sequential is a company focused on skin microbiome testing, utilizing advanced sequencing technologies to analyze skin microbial communities. We offer valuable insights into the microbiome profiles of individuals skin, enabling the development of personalized treatment plans. By collaborating with dermatologists and researchers, we contribute significantly to the advancement of microbiome-based diagnostics and therapeutics. Reference: Boxberger, M., Cenizo, V., Cassir, N .  Challenges in exploring and manipulating the  human skin microbiome. Microbiome  9, 125 (2021). https://doi.org/10.1186/s40168-021-01062-5 Callewaert C, Knödlseder N, Karoglan A, Güell M, Paetzold B. Skin microbiome  transplantation and manipulation: Current state of the art. Comput Struct Biotechnol J. 2021 Jan 4;19:624-631. doi: 10.1016/j.csbj.2021.01.001. PMID: 33510866; PMCID: PMC7806958. Junca H, Pieper DH, Medina E. The emerging potential of microbiome transplantation on  human health interventions. Comput Struct Biotechnol J. 2022 Jan 19;20:615-627. doi: 10.1016/j.csbj.2022.01.009. PMID: 35140882; PMCID: PMC8801967.