Vitamin A and its derivatives have become essential components of mainstream skincare products, popular for their anti-aging and anti-acne benefits. Yet, as we probe further into their effects on skin well-being, their interplay with the skin microbiome emerges as an avenue for exploration, extending beyond their established properties and into new realms of understanding and application. What We Know: Vitamin A deficiency has been associated with skin infection. However, the mechanism of how vitamin A provides skin immunity is not yet well understood (Harris et al., 2019). Human skin cells naturally produce Resistin protein, while in mice, epidermal keratinocytes and sebocytes produce a similar molecule known as Resistin-like molecule α (RELMα). Research showed that when activated by the vitamin A analog isotretinoin, RELMα exhibited antimicrobial properties. This effectively prevented skin infections and may suggest a similar property of Resistin activated by vitamin A in humans (Harris et al., 2019). When administered as a 0.025% cream for topical acne treatment, retinoic acid, a potent derivative of vitamin A, demonstrated notable results for individuals with mild acne vulgaris. Following one month of use, it exhibited efficacy in reducing bacterial diversity, reshaping microbiota composition and notably decreasing Cutibacterium acnes while elevating Staphylococcus epidermidis relative abundance (Wongtada et al., 2023). Industry Impact & Potential: Vitamin A and its derivatives have immunomodulatory properties that offer protection against fungal infections caused by Candida albicans, Aspergillus spp. and Microsporum spp. This suggests that investigating vitamin A derivatives such as retinoids in clinical settings could offer a promising therapeutic approach for treating fungal infections (Joshi et al., 2023). Understanding the role of vitamin A and its derivatives on both the innate immune system and the skin microbiome is crucial for advancing translational skin biology research and devising effective therapeutic approaches (Roche & Harris, 2021). Specifically, this can provide insight on disease progression and treatment responses, particularly regarding therapies targeting innate immune signalling and antimicrobial peptide production (Roche & Harris, 2021). Our Solution: At Sequential, we specialise in comprehensive Microbiome Product Testing, which is customisable to align with your unique product development and formulation goals. With our expert guidance and tailored services, we empower businesses to pioneer innovative strategies for topical solutions, such as creating microbiome-friendly products containing vitamin A and its derivatives, ensuring efficacy and compatibility for healthier skin. Reference List: Harris, T.A., Gattu, S., Propheter, D.C., Kuang, Z., Bel, S., Ruhn, K.A., Chara, A.L., Edwards, M., Zhang, C., Jo, J.-H., Raj, P., Zouboulis, C.C., Kong, H.H., Segre, J.A. & Hooper, L.V. (2019) Resistin-like Molecule α Provides Vitamin-A-Dependent Antimicrobial Protection in the Skin. Cell Host & Microbe. 25 (6), 777-788.e8. doi:10.1016/j.chom.2019.04.004. Joshi, M., Hiremath, P., John, J., Ranadive, N., Nandakumar, K. & Mudgal, J. (2023) Modulatory role of vitamins A, B3, C, D, and E on skin health, immunity, microbiome, and diseases. Pharmacological Reports. 75 (5), 1096–1114. doi:10.1007/s43440-023-00520-1. Roche, F. & Harris, T. (2021) Illuminating the Role of Vitamin A in Skin Innate Immunity and the Skin Microbiome: A Narrative Review. Nutrients. 13 (2). doi:10.3390/nu13020302. Wongtada, C., Prombutara, P., Asawanonda, P., Noppakun, N., Kumtornrut, C. & Chatsuwan, T. (2023) Distinct skin microbiome modulation following different topical acne treatments in mild acne vulgaris patients: A randomized, investigator-blinded exploratory study. Experimental Dermatology. 32 (6), 906–914. doi:10.1111/exd.14779.

Multiple factors are responsible for the makeup of the skin microbiome of an individual, including host genetics, age, hygiene practices, diet, nutrition, lifestyle, topical treatments and the environment. Research suggests that where we live can profoundly influence the microbial composition and overall health of our microbiomes. What We Know: Facial skin is impacted by external factors like climate, temperature, humidity, UV exposure and pollution, as it is more exposed to the environment compared to other skin (Proksch, 2008). Research that investigated the facial microbiome and metabolome across different geographic regions concluded that there were significant alterations in the abundance of multiple microorganisms between individuals (Tao et al., 2024). In a study across various regions in China, those residing in the northwest (in high altitude and dry climate) exhibited lower levels of Malassezia and bacterial diversity, as well as reduced total lipid content. However, they showed elevated levels of ceramides and fatty acids compared to individuals in southern regions (warm and wet climates) (Tao et al., 2024). Skin bacteria thrive in warm temperatures (33.2–35.0°C) with lipid-dependent organisms like Malassezia and Cutibacterium flourishing in such environments due to increased sebum secretion (Grice & Segre, 2011). Research also demonstrated that subjects living in rural areas exhibited significantly greater intra group variation in microbial community structure compared to urban subjects (Ying et al., 2015). Variations in bacterial populations across regions may be influenced by factors like humidity, UV exposure and temperature fluctuations. Higher humidity levels support greater bacterial diversity, while UV exposure alters the skin microbiome (Tao et al., 2024) Industry Impact and Potential: By analysing these aspects across geography, we can uncover climate-related influences on skin disorders, enabling tailored skincare recommendations for diverse regions (Tao et al., 2024). Increasing urbanisation correlates with higher levels of potentially pathogenic  bacteria and fungi, which may explain the urban prevalence of skin diseases like acne and atopic dermatitis. This highlights the need for urban-specific skincare, creating opportunities for specialised products and research (McCall et al., 2020). However, further research is necessary to fully elucidate the effects of environmental factors on the microbiome (Tao et al., 2024) Our Solution: Exploring environmental influence on the microbiome is a promising avenue for personalised skincare tailored to the individual needs of people globally. With three testing centres in distinct climates (New York, London and Singapore) Sequential offers comprehensive Microbiome Testing and guidance in product development and formulation, providing a toolkit for your company to delve into personalised skincare that considers our uniqueness. References: Grice, E.A. & Segre, J.A. (2011) The skin microbiome. Nature Reviews Microbiology. 9 (4), 244–253. doi:10.1038/nrmicro2537. McCall, L.-I., Callewaert, C., Zhu, Q., Song, S.J., Bouslimani, A., et al. (2020) Home chemical and microbial transitions across urbanization. Nature Microbiology. 5 (1), 108–115. doi:10.1038/s41564-019-0593-4. Proksch, E. (2008) Protection Against Dryness of Facial Skin: A Rational Approach. Skin Pharmacology and Physiology. 22 (1), 3–7. doi:10.1159/000159771. Tao, R., Li, T., Wang, Y., Wang, R., Li, R., Bianchi, P., Duplan, H., Zhang, Y., Li, H. & Wang, R. (2024) The facial microbiome and metabolome across different geographic regions. Microbiology Spectrum. 12 (1), e03248-23. doi:10.1128/spectrum.03248-23. Ying, S., Zeng, D.-N., Chi, L., Tan, Y., Galzote, C., Cardona, C., Lax, S., Gilbert, J. & Quan, Z.-X. (2015) The Influence of Age and Gender on Skin-Associated Microbial Communities in Urban and Rural Human Populations. PLOS ONE. 10 (10), e0141842. doi:10.1371/journal.pone.0141842.

Acne is a prevalent and multifactorial skin disease affecting teenagers and adults, generally stemming from an imbalance in the skin microbiome. Studies have shown that various essential oils (EOs) possess antimicrobial properties that can inhibit the growth of acne-causing bacteria strains like Cutibacterium acnes and Staphylococcus epidermidis. What We Know: Current acne treatments often involve topical or oral antibiotics, raising concerns about antibiotic resistance in C. acnes strains (Sardana et al., 2015). EOs are natural, concentrated liquids derived from plants, known for their aromatic properties and diverse biological characteristics, including bactericidal, virucidal and fungicidal properties (Cossetin et al., 2021). These include oregano, lavender, lemon grass, myrtle, lemon, thyme, eucalyptus, rosemary and tea tree EOs, which have all demonstrated anti-inflammatory, antioxidant and antimicrobial properties (Bungau et al., 2023). EOs are able to permeate the skin and facilitate the enhanced penetration of active compounds into deeper skin layers (Bungau et al., 2023). Their antimicrobial property occurs as their bioactive components target multiple cellular sites and interact with cell membranes, disrupting microbial integrity and ultimately causing cell death (Bungau et al., 2023). Industry Impact & Potential: Incorporating English lavender and peppermint EOs into gelatine nanofibers created effective topical patches for localised acne treatment by diminishing C. acnes and S. epidermidis (Uhlířová et al., 2023). Therefore, English lavender and peppermint EOs may be beneficial in the gentle and focused treatment of acne, as well as potentially other microbial-related skin conditions (Uhlířová et al., 2023). However, a challenge with EO use is their standardisation, which arises due to different cultivation conditions that produce EOs of varied quality, quantity and composition (Uhlířová et al., 2023). Methods for assessing antioxidant potential, such as determining total phenolic content, evaluating reducing power, measuring ferrous ion chelating activity, among other methods, are vital for gauging the efficacy and safety of essential oil use in acne treatment (Bungau et al., 2023). Future investigations could focus on developing innovative acne treatments incorporating essential oils and evaluating their effectiveness through large-scale clinical trials. Moreover, further research is warranted to elucidate the mechanisms of action of essential oils and identify their optimal doses and safety profiles for effective management of acne vulgaris (Bungau et al., 2023). Our Solution: At Sequential, we offer a comprehensive Microbiome Product Testing Solution, separately or in conjunction with guided product development and formulation services. This holistic approach enables your business to explore innovative methods for addressing skin conditions, like acne, using essential oils treatment strategies. Reference List: Bungau, A. F., Radu, A. F., Bungau, S. G., Vesa, C. M., Tit, D. M., Purza, A. L., & Endres, L. M. (2023). Emerging Insights into the Applicability of Essential Oils in the Management of Acne Vulgaris. Molecules (Basel, Switzerland) , 28(17), 6395. https://doi.org/10.3390/molecules28176395 Castellanos Lorduy, H. J., Pérez Cely, H. C., Casadiego Rincón, E. J., Henao Riveros, S. C., & Colorado, C. L. (2021). Cutibacterium acnes tetracycline resistance profile in patients with acne vulgaris, in a colombian dermatologic center. Actas Dermo-Sifiliográficas (English Edition), 112(10), 873-880. doi:10.1016/j.adengl.2021.09.003 Cossetin, L. F., Garlet, Q. I., Velho, M. C., Gündel, S., Ourique, A. F., Heinzmann, B. M., & Monteiro, S. G. (2021). Development of nanoemulsions containing lavandula dentata or myristica fragrans essential oils: Influence of temperature and storage period on physical-chemical properties and chemical stability. Industrial Crops and Products, 160, 113115. doi:10.1016/j.indcrop.2020.113115 Sardana, K., Gupta, T., Garg, V.,K., & Ghunawat, S. (2015). Antibiotic resistance to propionobacterium acnes: Worldwide scenario, diagnosis and management. Expert Review of Anti-Infective Therapy, 13(7), 883-896. doi:10.1586/14787210.2015.1040765 Uhlířová, R., Langová, D., Bendová, A., Gross, M., Skoumalová, P., & Márová, I. (2023). Antimicrobial Activity of Gelatin Nanofibers Enriched by Essential Oils against Cutibacterium acnes and Staphylococcus epidermidis. Nanomaterials (Basel, Switzerland), 13(5), 844. https://doi.org/10.3390/nano13050844

Elucidating the relationship between ceramides and the skin microbiome could revolutionise the treatment of skin disease. Ceramides, the lipid molecules abundant in the stratum corneum, play a crucial role in skin barrier function and alterations to their levels or profiles are associated with impaired barrier function and, in some cases, skin disease. What We Know: Ceramides are responsible for preventing water loss, maintaining skin moisture levels and ultimately maintaining skin barrier function (Baker et al., 2023). The breakdown of the skin barrier is a common feature of numerous inflammatory skin conditions and is well-understood in diseases like atopic dermatitis (AD) and psoriasis (Rajkumara et al., 2023). In the case of AD, patients generally have reduced ceramide levels (Elias et al., 2019). Regarding psoriasis, there is a reduction in the enzymes involved in ceramide biosynthesis and metabolism, causing a decrease in overall ceramides levels (Choi & Maibach, 2005). Staphylococcus epidermidis plays a role in skin barrier maintenance by secreting sphingomyelinase, an enzyme that facilitates the conversion of host cell sphingomyelin into ceramides (Zheng et al., 2022). Ceramides also play a role in maintaining the acidic mantle: a protective film that covers that surface of the skin with a pH 4.5-5.5, which is crucial for the proliferation of beneficial microorganisms like S. epidermidis (Baker et al., 2023). Industry Impact & Potential: Probiotic-type topical treatments, containing microbiota like S. epidermidis, show potential in treating skin diseases by leveraging their role in maintaining skin barrier integrity (Zheng et al., 2022). Researchers propose a targeted approach of screening the existing skin microbiome composition for deficiencies in S. epidermidis enzymes and subsequently treating the skin with strains that produce the lacking enzyme(s) in combination with direct bacterial interference mechanisms to eliminate harmful pathogens (Zheng et al., 2022). pH-optimised moisturisers enhance the chemical skin barrier by promoting optimal enzymatic activity that boosts ceramide synthesis, as well as creating favourable environments for beneficial microorganisms (Rajkumara et al., 2023). Mice models have shown that through the bacterial phenomenon of quorum sensing, commensal microbiota can inhibit Staphylococcus aureus toxin production (which is highly associated with AD symptoms), thus preventing skin barrier damage and inflammation (Williams et al., 2019). Our Solution: Sequential offers an end-to-end Microbiome Product Testing Solution, alongside guided product development and formulation services. Leveraging our expertise, we assist businesses in devising novel approaches to topical ceramide and/or probiotic-based treatments for various skin diseases and inflammatory conditions. Reference List: Baker, P., Huang, C., Radi, R., Moll, S. B., Jules, E., & Arbiser, J. L. (2023). Skin Barrier Function: The Interplay of Physical, Chemical, and Immunologic Properties. Cells, 12(23), 2745. https://doi.org/10.3390/cells12232745 Bouwstra, J. A., Helder, R. W. J., & El Ghalbzouri, A. (2021). Human skin equivalents: Impaired barrier function in relation to the lipid and protein properties of the stratum corneum. Advanced drug delivery reviews, 175, 113802. https://doi.org/10.1016/j.addr.2021.05.012 Choi, M. J., & Maibach, H. I. (2005). Role of ceramides in barrier function of healthy and diseased skin. American journal of clinical dermatology, 6(4), 215–223. https://doi.org/10.2165/00128071-200506040-00002 Elias, P. M., Wakefield, J. S., & Man, M. Q. (2019). Moisturizers versus Current and Next-Generation Barrier Repair Therapy for the Management of Atopic Dermatitis. Skin pharmacology and physiology, 32(1), 1–7. https://doi.org/10.1159/000493641 Rajkumar, J., Chandan, N., Lio, P., & Shi, V. (2023). The Skin Barrier and Moisturization: Function, Disruption, and Mechanisms of Repair. Skin pharmacology and physiology, 36(4), 174–185. https://doi.org/10.1159/000534136 Williams, M. R., Costa, S. K., Zaramela, L. S., Khalil, S., Todd, D. A., Winter, H. L., . . . Gallo, R. L. (2019). Quorum sensing between bacterial species on the skin protects against epidermal injury in atopic dermatitis. Science Translational Medicine, 11(490), eaat8329. doi:10.1126/scitranslmed.aat8329 Zheng, Y., Hunt, R. L., Villaruz, A. E., Fisher, E. L., Liu, R., Liu, Q., Cheung, G. Y. C., Li, M., & Otto, M. (2022). Commensal Staphylococcus epidermidis contributes to skin barrier homeostasis by generating protective ceramides. Cell host & microbe, 30(3), 301–313.e9. https://doi.org/10.1016/j.chom.2022.01.004

Alopecia (hair loss) can be caused by factors such as reduced physiological function, scalp tension-induced blood flow disorders, genetic predisposition and poor scalp nutrition. While microbiome-focused research into alopecia is limited, biomolecules of fermented fruits and fermenting microbes show promise as a potential solution. What We Know: Studies investigating the scalp microbiome determined that Cutibacterium spp. and Staphylococcus spp. make up approximately 90% of a healthy scalp microbiome, with the remaining 10% consisting of Corynebacterium spp., Streptococcus spp., Acinetobacter spp. and Prevotella spp (Jo et al., 2022). The scalp microbiome may impact scalp health and alopecia. Research indicates no variance in species diversity or abundance between alopecia-affected and healthy scalps. However, a study found a >10% difference in Proteobacteria and Actinobacteria distributions. Healthy scalps showed higher Proteobacteria abundance, while alopecia-affected scalps had higher Actinobacteria levels (Jo et al., 2022). Fermented aloe vera and kimchi were successfully used to treat burn wounds and improve the skin microbiota pattern, maintaining probiotic (saprophytic) bacteria, including Lactobacillus, and reducing pathogenic bacteria (such as Prevotella and Cutibacterium acnes) (Yoon et al., 2022; Park et al., 2020). Industry Impact and Potential: Hair care products containing fermented papaya and mangosteen improved hair shaft conditions and reduced hair loss compared to control groups, showing potential for alopecia (Mayer et al., 2023). These experimental products improved the scalp microbiota, correcting the alopecia-associated altered microbiota pattern by decreasing pathogen content whilst maintaining probiotic (saprophyte) levels (Mayer et al., 2023). Fermented papaya's probiotic activity may involve selectively inhibiting catalase in microbial pathogens, which they rely on for enzymatic antioxidant defence against the host's immune response (Mayer et al., 2023). Further studies are needed to explore the preclinical and clinical effects of using food-grade fermented products in cosmetics, aiming to better understand their mechanisms and potential benefits for hair health. Integrating phytochemical and biological experiments could help identify specific plant- and microbe-derived substances with hair loss prevention and hair quality enhancement properties (Mayer et al., 2023). Our Solution: With a vast database of over 20,000 microbiome samples and 4,000 ingredients, coupled with a global network of over 10,000 testing participants, Sequential offers comprehensive services to evaluate product impacts and formulations. Our customisable microbiome studies provide real-life context testing, while formulation support ensures products maintain biome integrity. Therefore, we are your ideal candidate to utilise our solutions for your product development and efficacy. References: Jo, H., Kim, S.Y., Kang, B.H., Baek, C., Kwon, J.E., Jeang, J.W., Heo, Y.M., Kim, H.-B., Heo, C.Y., Kang, S.M., Shin, B.H., Nam, D.Y., Lee, Y.-G., Kang, S.C. & Lee, D.-G. (2022) Staphylococcus epidermidis Cicaria, a Novel Strain Derived from the Human Microbiome, and Its Efficacy as a Treatment for Hair Loss. Molecules. 27 (16). doi:10.3390/molecules27165136. Mayer, W., Weibel, M., De Luca, C., Ibragimova, G., Trakhtman, I., Kharaeva, Z., Chandler, D.L. & Korkina, L. (2023) Biomolecules of Fermented Tropical Fruits and Fermenting Microbes as Regulators of Human Hair Loss, Hair Quality, and Scalp Microbiota. Biomolecules. 13 (4), 699. doi:10.3390/biom13040699. Park, D.-W., Lee, H.S., Shim, M.-S., Yum, K.J. & Seo, J.T. (2020) Do Kimchi and Cheonggukjang Probiotics as a Functional Food Improve Androgenetic Alopecia? A Clinical Pilot Study. The World Journal of Men’s Health. 38 (1), 95–102. doi:10.5534/wjmh.180119. Yoon, Y.C., Ahn, B.H., Min, J.W., Lee, K.R., Park, S.H. & Kang, H.C. (2022) Stimulatory Effects of Extracellular Vesicles Derived from Leuconostoc holzapfelii That Exists in Human Scalp on Hair Growth in Human Follicle Dermal Papilla Cells. Current Issues in Molecular Biology. 44 (2), 845–866. doi:10.3390/cimb44020058.

Sudden skin reactions to skincare products can result from various factors, such as the introduction of new allergens, shifts in skin sensitivity, and the cumulative impact of product usage. Understanding these responses involves examining the allergens in cosmetics, the mechanisms behind skin reactions, and the influence of individual skin conditions. Types of allergens in skincare products Fragrance and preservatives: Common allergens like fragrances such as hydroxyisohexyl-3-cyclohexene carboxaldehyde, and preservatives like formaldehyde, parabens are frequently associated with allergic contact dermatitis (White & Groot, 2011). These ingredients can sensitize the skin over time, making it more reactive with continued exposure. Hair dyes: Ingredients such as p-phenylenediamine, often found in hair dyes, can cause allergic reactions, including redness, swelling, and itching around the scalp and face (White & Groot, 2011). Plant and Animal Derivatives: Natural components derived from plants and animals can provoke skin reactions, especially in sensitive individuals. Examples include lanolin, often derived from sheep's wool, and botanical extracts (Verhulst & Goossens, 2016). Alcohols and Acids:   Alcohols and exfoliating agents like glycolic acid or salicylic acid are popular in skincare for their renewing properties. However, they can irritate sensitive or damaged skin, causing redness and burning sensations (Verhulst & Goossens, 2016). Mechanisms of skin reactions Immediate Contact Reactions:  Some people experience Contact Urticaria Syndrome (CUS), where symptoms such as wheals or redness appear within minutes of exposure to a certain substance (Giménez-Arnau et al., 2010). Cumulative Sensitization: Repeated exposure to certain allergens can lead to cumulative sensitization, where skin that initially tolerated a product begins to react adversely over time (Wolf et al ., 2001). Skin Barrier Dysfunction:  A compromised skin barrier, due to over-exfoliation, dehydration, or pre-existing conditions becomes more permeable to irritants and allergens, increasing the risk of reactions (Engebretsen & Thyssen, 2016). Individual Factors Influencing Reactions Skin type:  People with sensitive skin, eczema, or rosacea are more prone to adverse reactions to skincare products. These conditions make the skin barrier more fragile and reactive. Age and Hormonal Changes: Aging skin or hormonal fluctuations, such as those occurring during pregnancy or menopause, can alter the skin's physiology, making it more sensitive and less resilient. Environmental Stressors: External factors like climate changes, UV exposure, pollution, or high stress can exacerbate skin sensitivity, increasing the likelihood of adverse reactions. Conclusion Most cosmetic products are considered safe for use, and proper diagnostic tools, such as patch testing, play a crucial role in identifying specific allergens and distinguishing between allergic and irritant reactions, enabling effective management and prevention strategies (Lazzarini, Duarte & Ferreira, 2013). Understanding the intricate mechanisms behind these reactions is essential for maintaining skin health. References Engebretsen KA, Thyssen JP. Skin Barrier Function and Allergens. Curr Probl Dermatol.  2016;49:90-102. doi: 10.1159/000441548. Epub 2016 Feb 4. PMID: 26844901. Lazzarini R, Duarte I, Ferreira AL. Patch tests. An Bras Dermatol. 2013  Nov-Dec;88(6):879-88. doi: 10.1590/abd1806-4841.20132323. PMID: 24474094; PMCID: PMC3900336. Wolf, R., Wolf, D., Tuzun, B., & Tuzun, Y. (2001). Cosmetics and contact dermatitis.  Dermatologic Therapy, 14(3), 181–187. doi:10.1046/j.1529-8019.2001.01025.x  White, Jonathan & De Groot, Anton - Ton & White, Ian. (2011). Cosmetics and Skin Care  Products. 10.1007/978-3-642-03827-3_32.  Verhulst L, Goossens A. Cosmetic components causing contact urticaria: a review and  update. Contact Dermatitis. 2016 Dec;75(6):333-344. doi: 10.1111/cod.12679. Epub 2016 Sep 4. PMID: 27593503.

Testing skincare products requires a structured approach to assess the products effectiveness and safety. This involves various methods, including in vitro testing, and clinical trials. As a consumer, testing skincare requires the products compatibility with personal needs. These testing include methods such as in-store testing, and patch testing. Testing methodologies  In vitro testing In vitro testing plays a critical role in assessing the safety and efficacy of skincare products. Under the European legislation, the evaluation of individual cosmetic ingredients is essential, with a strict prohibition on animal testing for cosmetic ingredients and products since 2004 and 2009, respectively. Additionally, the sale of products containing ingredients tested on animals has been banned since 2009 (Almeida, Sarmento & Rodrigues, 2017).  To meet these regulatory requirements, the European Centre for the Validation of Alternative Methods (ECVAM) has developed and validated various in vitro models such as skin irritation potential on cultured human or mammalian cell lines, skin cytotoxicity, skin and eye corrosion and irritation, phototoxicity…etc, to predict the safety and toxicity of cosmetic ingredients. These cell-based systems are valuable tools that provide reliable alternatives to animal testing, enabling researchers to evaluate factors such as absorption, permeability, and potential toxicity  (Almeida, Sarmento & Rodrigues, 2017).  Clinical trials Clinical trials are crucial for evaluating the performance of skincare products on human subjects. They consist of different phases and each phase typically involves a significant number of participants and incorporate both subjective feedback and objective assessments.  For example, a 4-week clinical study with 176 participants tested five targeted skincare formulations addressing irritated skin, dry skin, aging skin, oily skin, and dark circles. Results from the clinical study showed significant improvements in all conditions, with the products proving effective and safe, and no adverse effects (Duschek et al ., 2022). Consumer evaluation methods In store testing This allows consumers to directly observe the immediate effects of a skincare product on their skin. By evaluating factors such as texture, absorption, and any visible improvements, such as reduced redness or smoother skin, consumers can gain insight into the product's performance. This first hand observation is important, as it provides a sense of how the product may work for their individual skin needs. Patch testing Before using a new skincare product, it's advised to do a patch test. This involves applying a small amount of the product to a small area of your skin, like behind your ear or on your wrist, and leaving it for a certain period of time (usually 24-48 hours). This allows you to check for any signs of irritation, redness, or allergic reaction before applying the product to larger areas of your skin. It's a simple way to test if the product is safe to use. Conclusion In conclusion, testing skincare products is a crucial step in ensuring the products safety, effectiveness, and suitability for individual skin needs. There are a variety of testing methods that help provide a comprehensive understanding of how products perform. While in vitro models offer an ethical alternative to animal testing and clinical trials provide valuable insights into product performance, consumer methods are crucial to allow individuals to assess the product's compatibility with their own skin.  References Almeida, A., Sarmento, B., & Rodrigues, F. (2017). Insights on in vitro models for safety and  toxicity assessment of cosmetic ingredients. International Journal of Pharmaceutics, 519(1-2), 178–185. doi:10.1016/j.ijpharm.2017.01.024  Duschek N, Cajkovsky M, Prinz V, Müller D, Hundsamer A, Baierl A, Möllhoff N, Sulovsky M,  Frank K. An open-label, 4-week, prospective clinical study evaluating the efficacy and safety of a novel targeted skin care line addressing five common skin conditions. J Cosmet Dermatol. 2022 Nov;21(11):5760-5768. doi: 10.1111/jocd.15223. Epub 2022 Jul 28. PMID: 35810352.

The reason that skin appears healthier without the use of skincare products stems from various factors, such as, over-cleansing, and certain products could contain ingredients that may irritate skin. Therefore, simplifying skincare routines could enhance the skin’s natural balance and appearance.  Over-cleansing and skin health Over-cleansing is a key factor in improved skin appearance when skincare is avoided, as excessive washing strips the skin of its natural oils, causing dryness and irritation. A study done by Sverdrup showed that dry skin which is common in fibromyalgia patients' skin worsened by cosmetic use and aggressive cleansing routines (Sverdrup, 2004). The skin's natural oils are essential for hydration and maintaining the barrier function and their excess removal can trigger increased oil production, creating a cycle of dryness and oiliness that impacts the skin's overall appearance (Güell & Schneider, 2023). Irritation from ingredients Many skincare products contain chemicals and fragrances that can irritate the skin, causing redness, breakouts, or other adverse reactions. The growing popularity of "free from" claims in cosmetics reflects concerns about allergens and irritants, with avoiding such products potentially reducing irritation and promoting clearer skin (Nobile, 2016).  Regular use of products with harsh ingredients can also increase skin sensitivity, making it more reactive to environmental factors, while minimizing product use may help restore the skin’s natural resilience. Moreover, the skin has an ability to maintain its health and appearance when allowed to function naturally. The epidermis, the skin's outermost layer, acts as a protective barrier against environmental stressors. Discontinuing the use of potentially irritating products enables the skin to restore its natural balance and operate more efficiently (Lim, 2021). A study involving different age groups and lifestyles found that ceasing the use of potentially irritating products allowed the skin to restore its natural hydration and protective barrier, resulting in noticeable improvements. Younger individuals and new mothers, who often have less time for self-care, reported significant boosts in skin appearance and self-esteem when following simple skincare routines, highlighting how excessive or misused products can sometimes overwhelm the skin (Zhang et al ., 2020). The skin's microbiome plays a vital role in maintaining skin health as well. Overuse of cleansers and other products can disrupt the delicate balance of beneficial bacteria on the skin, leading to conditions such as acne or eczema (Hwang et al ., 2021). Hence it is important to incorporate products that support the skin microbiome rather than hindering it. Conclusion While a simplified approach to skincare may improve skin appearance for some individuals by reducing irritation and allowing the skin’s natural functions to flourish, it is important to balance this approach with targeted and purposeful skincare. Over-cleansing and the use of harsh or unsuitable products can disrupt the skin barrier, leading to cycles of dryness, oiliness, and sensitivity. However, well-formulated skincare routines that incorporate gentle cleansers, moisturizers, and sun protection can enhance the skin's resilience and prevent long-term damage from environmental stressors. Ultimately, the key to healthy skin lies in understanding individual skin needs and using products that support the balance of the skin. References Güell M, Schneider MR. In preprints: progress in sebaceous gland homeostasis,  regeneration and immunomodulatory functions. Development. 2023 Aug 1;150(15):dev202177. doi: 10.1242/dev.202177. Epub 2023 Jul 31. PMID: 37522362. Hwang BK, Lee S, Myoung J, Hwang SJ, Lim JM, Jeong ET, Park SG, Youn SH. Effect of  the skincare product on facial skin microbial structure and biophysical parameters: A pilot study. Microbiologyopen. 2021 Oct;10(5):e1236. doi: 10.1002/mbo3.1236. PMID: 34713611; PMCID: PMC8494714. Lim KM. Skin Epidermis and Barrier Function. Int J Mol Sci. 2021 Mar 16;22(6):3035. doi:  10.3390/ijms22063035. PMID: 33809733; PMCID: PMC8002265. Nobile, Vincenzo. “Misleading Marketing of Cosmetics. Do the Free from Parabens and Free  from Allergenic Substances Claims Really Make Sense.” (2016). Sverdrup B. Use less cosmetics--suffer less from fibromyalgia? J Womens Health (Larchmt).  2004 Mar;13(2):187-94. doi: 10.1089/154099904322966173. PMID: 15072733. Zhang, L., Adique, A., Sarkar, P., Shenai, V., Sampath, M., Lai, R., … & Farage, M. A.  (2020). The impact of routine skin care on the quality of life. Cosmetics, 7(3), 59. https://doi.org/10.3390/cosmetics7030059

Calculating skincare ingredients requires a structured approach that considers the components, proportions, and interactions involved in creating effective formulations. This process is crucial to ensure the final product achieves the desired efficacy and adheres to safety standards. Water as a Base   Water typically constitutes 55% to 80% of most skincare formulations. It serves as a solvent and carrier, enabling other ingredients to be absorbed effectively into the skin (Moldovan et al ., 2017).   Active Ingredients  Active ingredients deliver targeted benefits such as hydration, anti-aging effects, or sun protection. For example, formulations might include 3–5% herbal extracts or 15–20% sun-blocking agents like avobenzone (National Academies of Sciences, Engineering, and Medicine 2022). Emollients and Oils  Emollients and oils are used to moisturize and soften the skin. Their proportions can vary significantly, with some formulations containing up to 20% oil-based agents (Tomokazu & Hidehiro, 2014). Formulations are often expressed in mass percentages for simplicity. For instance, in a 100-gram product, a 5% concentration of an active ingredient would equate to 5 grams (Tomokazu & Hidehiro, 2014). Ingredient Interaction and Stability   Compatibility Testing   Evaluating how different ingredients interact is vital. For example, some herbal extracts may enhance or diminish the efficacy of other active ingredients, requiring careful adjustment of their ratios (Panico et al ., 2019). Preservatives and Stabilizers  These ingredients play a critical role in extending the shelf life of skincare products. Preservative ratios typically range from 0.5% to 1.5%, depending on the water content of the formulation and its susceptibility to microbial growth (Varvaresou et al ., 2009).   The formulation process often involves various adjustments based on results from stability testing and consumer feedback. This ensures the final product meets both efficacy and sensory expectations. Conclusion In conclusion, calculating ingredient ratios for skincare formulations requires a precise and methodical approach, and by understanding the roles of key ingredients, conducting compatibility tests, formulators can create effective, and safe skincare products. References Moldovan M, Lahmar A, Bogdan C, Părăuan S, Tomuţă I, Crişan M. Formulation and  evaluation of a water-in-oil cream containing herbal active ingredients and ferulic acid. Clujul Med. 2017;90(2):212-219. doi: 10.15386/cjmed-668. Epub 2017 Apr 25. PMID: 28559707; PMCID: PMC5433575. National Academies of Sciences, Engineering, and Medicine 2022. Review of Fate, Exposure, and Effects of Sunscreens in Aquatic Environments and Implications for Sunscreen Usage and Human Health . Washington, DC: The National Academies Press. https://doi.org/10.17226/26381 . Panico A, Serio F, Bagordo F, Grassi T, Idolo A, DE Giorgi M, Guido M, Congedo M, DE Donno  A. Skin safety and health prevention: an overview of chemicals in cosmetic products. J Prev Med Hyg. 2019 Mar 29;60(1):E50-E57. doi: 10.15167/2421-4248/jpmh2019.60.1.1080. PMID: 31041411; PMCID: PMC6477564. Tomokazu, Yoshida., Hidehiro, Nagasawa. (2014). Skin cosmetic composition Varvaresou, Athanasia & Papageorgiou, Spyridon & Tsirivas, E & Protopapa, Evangelia &  Kintziou, H & Kefala, Vasiliki & Demetzos, Costas. (2009). Self-preserving cosmetics. International journal of cosmetic science. 31. 163-75. 10.1111/j.1468-2494.2009.00492.x.

What is the microbiome? The human microbiome is defined as the full array of microorganisms, and their genomes, that live in and on humans. These microorganisms inhabit a particular site of the human body and form distinct microbial communities (microbiota) such as those found on the skin or the scalp microbiome. The composition of an individual's microbiome can be influenced by several factors such as age, environment and method of birth.   Without testing, there are a few signs that can indicate whether your microbiome is potentially off-balance. An imbalance in the microbiome, also known as dysbiosis, can manifest as a condition in different body areas such as acne vulgaris or dandruff. In this post, we explore potential signs of imbalance in the skin, scalp, oral and vaginal microbiomes.    Signs of a skin microbiome imbalance Skin-resident microbes inherently help to maintain a healthy skin barrier, however, if disrupted, changes in the skin microbiome can lead to inflammation, dryness, irritation and itchy skin (Skowron et al ., 2021). Several studies have also shown that dysbiosis is implicated in the manifestation of inflammatory skin conditions such as acne and atopic dermatitis.    Acne One of the major factors involved in acne pathogenesis is thought to be an imbalance of the bacteria Cutibacterium acnes . Although C.acnes  is also present on healthy skin, studies show that a loss of microbial diversity and loss of balance between C. acnes  phylotypes appears to play a role in the triggering of acne (Dréno et al. , 2020).   Atopic Dermatitis (Eczema)  Studies have shown that individuals with atopic dermatitis have a disturbed skin microbiome and are more often colonised with Staphylococcus aureus  compared to healthy individuals. The presence of S. aureus  contributes to the inflamed, dry and itchy skin commonly experienced by individuals with atopic dermatitis.   Signs of a scalp microbiome imbalance Studies have revealed that the scalp microbiome is characterized by a relatively low bacterial diversity, as compared to the other body sites and is dominated by Cutibacterium acnes , Staphylococcus epidermidis  and Malassezia  spp (Saxena et al., 2021) . Dysbiosis of the scalp microbiome has been linked to conditions such as seborrheic dermatitis and dandruff.   Seborrheic Dermatitis Seborrheic dermatitis is a common chronic, inflammatory skin disease that can affect the scalp and other sebum-gland-rich areas of the body. Scalp seborrheic dermatitis (SD) is a chronic type of inflammatory dermatosis associated with the proliferation of Malassezia  species (Wang et al., 2021). The common signs of seborrheic dermatitis are flaking, scaling and inflammation.   Dandruff Dandruff is a light disease state of seborrheic dermatitis, also associated with the proliferation of Malassezia species. Thus, scalp microbiome dysbiosis may present itself as dandruff, characterised by mild inflammatory reactions that present as abnormal flaking of the scalp and sometimes with mild erythema (redness).   Signs of an oral microbiome imbalance The oral microbiome comprises a complex and diverse community of microorganisms living within the oral cavity and is the third most diverse after the gut and skin microbiome. Changes in the oral cavity can lead to dysbiosis which has been associated with the development of diseases such as periodontitis and gingivitis.   Periodontitis (Gum Disease) Periodontitis, otherwise known as gum disease, is an irreversible inflammatory condition that affects over half of the world’s population and is a major cause of tooth loss. Although the cause of periodontitis is multifactorial, the presence of plaque is thought to be the primary factor. Plaque is formed when salivary glycoproteins adhere to the tooth surface, creating an environment for both Gram-positive and Gram-negative bacteria to colonise. It is the uncontrolled growth of the Gram-negative component of subgingival biofilm that leads to periodontitis (Aruni et al.,  2015). Common signs of periodontitis include persistent bad breath, swollen gums and loose teeth.   Gingivitis Gingivitis and periodontitis are a continuum of the same inflammatory disease, whereby gingivitis may lead to periodontitis if left untreated. Dysbiosis in the oral microbiome may manifest as gingivitis which is characterised by red, swollen and bleeding gums.   Signs of a vaginal microbiome imbalance  Vaginal microbiota constitutes about 9% of the total human microbiota. These microbes live in a mutualistic relationship with the host vagina protecting it from potentially pathogenic microbes like those causing bacterial vaginosis (Saraf et al., 2021).   Bacterial Vaginosis Changes in the vaginal microbiota including a loss of Lactobacillus species and an increase in facultative and anaerobic organism populations result in bacterial vaginosis (Saraf et al. , 2021). This imbalance in the vaginal microbiome often leads to unusual discharge.   In summary Whilst these signs can indicate a potential imbalance in your microbiome, they can also be caused by other factors. Microbiome testing would be ideal to provide certainty of an imbalance, however not many personal care brands offer this method of diagnosis to consumers. One example of a skincare brand that does offer this service is Gallinée, enabling personalised skin routine recommendations via an in-depth skin health report.   Advice for brands We recommend differentiating your brand by harnessing the power of microbiome testing. The results of our market research on over 3,500 participants found that 80% demand a customised microbiome-based skincare product that factors ethnicity, age, location and skin concerns. By conducting in vivo  testing on your products you can ensure they maintain the microbiome. Additionally, we can partner with your brand to offer our at-home skin microbiome testing kit, allowing you to provide skin health reports and personalised product recommendations to your customers based on their individual microbiome profiles.   References   Aruni, A. W., Dou, Y., Mishra, A., & Fletcher, H. M. (2015). The biofilm community: Rebels with a cause.  Current Oral Health Reports, 2 (1), 48-56. doi:10.1007/s40496-014-0044-5   Dréno, B., Dagnelie, M. A., Khammari, A., & Corvec, S. (2020). The skin microbiome: A new actor in inflammatory acne.  American Journal of Clinical Dermatology, 21 (Suppl 1), 18-24. doi:10.1007/s40257-020-00531-1   Saraf, V. S., Sheikh, S. A., Ahmad, A., Gillevet, P. M., Bokhari, H., & Javed, S. (2021). Vaginal microbiome: Normalcy vs dysbiosis.  Archives of Microbiology, 203 (7), 3793-3802. doi:10.1007/s00203-021-02414-3   Saxena, R., Mittal, P., Clavaud, C., Dhakan, D. B., Roy, N., Breton, L., . . . 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   Skowron, K., Bauza-Kaszewska, J., Kraszewska, Z., Wiktorczyk-Kapischke, N., Grudlewska-Buda, K., Kwiecińska-Piróg, J., . . . Gospodarek-Komkowska, E. (2021). Human skin microbiome: Impact of intrinsic and extrinsic factors on skin microbiota.  Microorganisms (Basel), 9 (3), 543. doi:10.3390/microorganisms9030543   Wang, H., Wang, C., Hsieh, S., Hung, Y., & Chen, H. (2022). Evaluation of a new‐formula shampoo containing 6% glycyrrhetinic acid complex for scalp seborrheic dermatitis: A pilot study.  Journal of Cosmetic Dermatology, 21 (8), 3423-3430. doi:10.1111/jocd.14623

The microbiome refers to the collection of trillions of microorganisms, such as bacteria, fungi, and viruses, that live in and on your body, particularly in your gut. (Lloyd-Price, Abu-Ali & Huttenhower, 2016) These microbes are vital components in maintaining our health by aiding digestion, regulating the immune system, and even influencing mood and overall brain function. Given the growing interest in the microbiome's impact on overall well-being, testing the microbiome has broadened its appeal among people. Here's an overview of the process, why it's important, and what the results could reveal. Types of Microbiome Tests Skin tests:   Skin microbiome samples are typically collected using non-invasive methods, such as swabs, tape strips, or skin scrapings. A swab is gently rubbed over the surface of the skin to capture microbial communities from different body areas, depending on the research or diagnostic needs. These samples are then sent to a lab for DNA sequencing to identify and quantify the microbial species present (Grice & Segre, 2011). This approach allows for a deeper understanding of how the skin's microbial balance impacts health conditions like acne, eczema, and skin infections. Saliva tests:  Saliva microbiome testing is a non-invasive approach to assess the bacterial communities in the mouth, offering insights into oral and overall health. Through next-generation sequencing, saliva samples can reveal significant shifts in microbial composition, serving as early biomarkers for health conditions.For example, Aas et al. (2005) demonstrated that saliva microbiome testing could reveal distinct bacterial profiles associated with oral diseases, suggesting its importance in both oral and systemic health management. Stool tests : Stool microbiome testing evaluates the gut’s microbial composition by analysing bacteria, viruses, and fungi in stool samples. This non-invasive test helps identify microbial imbalances (dysbiosis) linked to conditions like irritable bowel syndrome, inflammatory bowel disease, and metabolic disorders. By using next-generation sequencing, it reveals the diversity and abundance of gut microbes, which can inform insights into digestive, immune, and even mental health. Zhernakova et al. (2016) highlighted its potential in detecting gut-related health issues and promoting personalised healthcare strategies. Comprehensive clinical tests:   In some cases, healthcare providers may recommend a more comprehensive testing that goes beyond the standard saliva and stool samples which include blood tests or even tissue biopsies; particularly when chronic conditions are present. These approaches can hold valuable information regarding systemic infections or localised imbalances in microbiota, which can significantly aid in the management of diseases such as inflammatory bowel disease and even cancer. (Schulfer & Blaser, 2015) Conclusion By testing our microbiome, we dive into important insights of our overall health by identifying imbalances in microbial communities, known as dysbiosis, which are interlinked to various health conditions. Understanding our microbiome composition allows for customised dietary and lifestyle adjustments to restore balance, as specific gut bacteria are essential for digestion, immune function, and mood regulation. (Zhernakova et al., 2016; Young, 2017) Advancements in microbiome research show that testing can aid in managing chronic diseases by guiding personalised treatment and dietary plans based on an individual's microbial profile, improving clinical outcomes and overall well-being (Lloyd-Price et al., 2016; Hu et al., 2021). Regular testing can optimise health, particularly concerning the gut-brain axis and metabolic health. References Aas, J. A., Paster, B. J., Stokes, L. N., Olsen, I., & Dewhirst, F. E. (2005). Defining the normal bacterial flora of the oral cavity. Journal of Clinical Microbiology, 43(11), 5721-5732. https://doi.org/10.1128/JCM.43.11.5721-5732.2005 Lloyd-Price, J., Abu-Ali, G., & Huttenhower, C. (2016). The healthy human microbiome. Genome Medicine, 8(51), 1-11. https://doi.org/10.1186/s13073-016-0307-y Schulfer , A., & Blaser, M. J. (2015). Risks of antibiotic exposures early in life on the developing microbiome. PLoS Pathogens, 11(7), e1004903. https://doi.org/10.1371/journal.ppat.1004903 Zhernakova, A., et al. (2016). Population-based metagenomics analysis reveals markers for gut microbiome composition and diversity. Science, 352(6285), 565-569. https://doi.org/10.1126/science.aad3369

As interest in the human microbiome grows, various microbiome tests have emerged, each offering unique insights into our health. Understanding which tests are best suited for individual needs can help inform decisions regarding health management and lifestyle changes. Skin Microbiome Testing Skin microbiome testing involves collecting samples from the skin's surface using methods like swabs, tape strips, or skin scrapings to analyse the diversity and composition of microorganisms residing on the skin. The samples are then processed through DNA sequencing techniques to identify microbial species and their relative abundance. This testing provides insights into how the skin's microbial ecosystem impacts health conditions such as acne and eczema. Skin microbiome research is increasingly being used to develop personalised skincare products and therapeutic approaches (Byrd et al., 2018). Stool Microbiome Testing Stool testing remains one of the most common and accessible methods for analysing the gut microbiome. These tests evaluate the diversity and abundance of microbial species, helping to identify imbalances linked to conditions such as irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and obesity. A study by Zhernakova et al. (2016) emphasises the utility of stool microbiome tests in detecting dysbiosis and understanding its relationship to health outcomes. Saliva Microbiome Testing Saliva microbiome testing is another non-invasive method, focusing on the oral microbiota. This test can provide insights into oral health, periodontal disease, and even systemic health conditions linked to the oral microbiome. A study by Aas et al. (2005) illustrates that the oral microbiome reflects changes in health status, making saliva testing an essential tool for early disease detection. Blood Microbiome Testing While less common, blood microbiome testing is gaining traction, especially for identifying systemic infections or chronic conditions. This testing method analyses microbial DNA present in the bloodstream, which can reveal insights into conditions like sepsis and cardiovascular diseases.  A paper by Cheng et al. (2023) reviews the emerging concept of the blood microbiome, highlighting its potential role in human health and disease, while addressing existing controversies and the need for further research to understand its clinical implications. Tissue Biopsy Microbiome Testing Tissue biopsies are increasingly utilised for studying the microbiome within specific organs, particularly the gastrointestinal tract. This method allows for direct analysis of microbial communities in tissue samples, providing insights into diseases such as colorectal cancer and IBD. Recent advancements in next-generation sequencing have enhanced the ability to identify and characterise microbial populations in biopsies, as noted by Schulfer and Blaser (2015). Conclusion Choosing the right microbiome test depends on individual health concerns and goals. Stool and saliva tests are excellent for general gut and oral health insights, while blood and tissue tests offer deeper analysis for chronic diseases. As research continues to evolve, these tests will likely become even more integral to personalised healthcare and preventative strategies. References Aas, J. A., Paster, B. J., Stokes, L. N., Olsen, I., & Dewhirst, F. E. (2005). Defining the normal bacterial flora of the oral cavity. Journal of Clinical Microbiology, 43(11), 5721-5732. https://doi.org/10.1128/JCM.43.11.5721-5732.2005 Byrd , A. L., Belkaid, Y., & Segre, J. A. (2018). The human skin microbiome. Nature Reviews Microbiology, 16(3), 143-155. https://doi.org/10.1038/nrmicro.2017.157 Cheng , H. S., Tan, S. P., Wong, D. M. K., Koo, W. L. Y., Wong, S. H., & Tan, N. S. (2023). The blood microbiome and health: Current evidence, controversies, and challenges. International Journal of Molecular Sciences, 24(6), 5633. https://doi.org/10.3390/ijms24065633 Schulfer, A., & Blaser, M. J. (2015). Risks of antibiotic exposures early in life on the developing microbiome. PLoS Pathogens, 11(7), e1004903. https://doi.org/10.1371/journal.ppat.1004903 Zhernakova, A., Kurilshikov, A., Bonder, M. J., Tigchelaar, E. F., Schirmer, M., Vatanen, T., ... & Wijmenga, C. (2016). Population-based metagenomics analysis reveals markers for gut microbiome composition and diversity. Science, 352(6285), 565-569. https://doi.org/10.1126/science.aad3369