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Skin aging is a progressive phenomenon influenced by intrinsic factors (chronological, hormonal, genetic) as well as extrinsic factors such as UV radiation exposure, pollution, and smoking (1,2). This process leads to epidermal atrophy, reduced density of fibroblasts and collagen, alterations of the stratum corneum, and a diminished ability to retain moisture (1). These changes result in thinner, drier skin that is more vulnerable to infections, slow healing, and certain dermatological conditions (2).
Aging also induces profound functional modifications: a reduction in sebaceous and sweat glands, decreased nutrient supply, and an increase in skin pH, all contributing to a weakened skin barrier (2,3). Photoaging, mainly caused by sun exposure, amplifies these effects by altering the lipid structure of the skin and triggering chronic inflammation (1).
The skin microbiome, comprising all microorganisms living on the skin’s surface, closely interacts with the cutaneous environment. Although relatively stable over the medium term, its composition changes significantly with age (4). A study reported by Boxberger et al. identified aging as one of the four main factors influencing variations in the skin microbiome, along with lifestyle, demographic characteristics, and pigmentation (4).
As we age, modifications of the skin microenvironment such as increased pH, reduced sebum production, and tissue atrophy, alter the habitat of these microorganisms. This leads to a decrease in certain protective commensal species like Cutibacterium acnes, and a proliferation of other genera such as Corynebacterium, Proteobacteria, and even Acinetobacter. Meanwhile, research has shown that some microbiome strains can also act on the skin itself: by modulating pH through lipid metabolism (as with C. acnes), stimulating keratinocyte proliferation, or promoting ceramide production, which is essential for maintaining hydration. Thus, the relationship between skin aging and its microbiome is bidirectional (1,2).
Studies have observed an increase in the alpha diversity of the skin microbiota in older individuals, indicating a more diverse yet potentially less stable ecosystem. This heightened diversity can facilitate the establishment of opportunistic pathogens, reflecting a loss in the dominance of beneficial species (1,3). For instance, some studies have noted a higher incidence of erythrasma, an infection associated with the proliferation of Corynebacterium, among elderly populations (2).
Aging is also associated with a decline in cutaneous immune functions, such as keratinocyte activation, the production of antimicrobial peptides, and the regulation of inflammatory responses (2,3). At the same time, the reduction of commensal microbes capable of producing protective compounds like cutimycin from Cutibacterium, limits the skin’s defenses against pathogenic species such as Staphylococcus aureus (2).
In older individuals, the skin thus becomes more alkaline, less hydrated, and less able to maintain an effective functional barrier. These conditions promote the emergence of cutaneous dysbiosis, which can exacerbate inflammatory states or slow down wound healing (1,3).
Current knowledge highlights the central role of the microbiome in skin aging. This understanding paves the way for new preventive and corrective strategies, notably through the integration of probiotics, prebiotics, and postbiotics into anti-aging cosmetic care (2).
Strains such as Lactobacillus plantarum and Bifidobacterium breve have demonstrated their ability to limit the effects of oxidative stress and UV exposure, strengthen the barrier function, and reduce the production of pro-inflammatory cytokines (2). Such strategies could offer a means to maintain microbiome stability for longer and help mitigate the signs of aging.
At BYOME LABS, we place the microbiome at the heart of cosmetic innovation. Our services help brands by providing testing and analysis to develop formulations tailored to mature skin, scientifically assessing their compatibility with the skin microbiome.
In particular, we offer in vitro models that mimic the compositional variations of the microbiome found in mature skin, as well as testing your products on this specific type of microbiome.
Skin aging is a multidimensional process in which the interactions between the skin and its microbiome play a crucial role. These changes are not only visible, they can also be measured at the microbiological level. Integrating microbiome biology into the development of anti-aging skincare represents a true revolution in cosmetics and dermocosmetics. With its expertise, BYOME LABS supports this transition by helping develop innovative, tailored, and scientifically validated skincare solutions.
1. Lee H, Hong Y, Kim M. Structural and Functional Changes and Possible Molecular Mechanisms in Aged Skin. Int J Mol Sci. 19 nov 2021;22(22):12489.
2. Woo YR, Kim HS. Interaction between the microbiota and the skin barrier in aging skin: a comprehensive review. Front Physiol. 19 janv 2024;15:1322205.
3. Howard B, Bascom CC, Hu P, Binder RL, Fadayel G, Huggins TG, et al. Aging-Associated Changes in the Adult Human Skin Microbiome and the Host Factors that Affect Skin Microbiome Composition. J Invest Dermatol. 1 juill 2022;142(7):1934-1946.e21.
4. Boxberger M, Cenizo V, Cassir N, La Scola B. Challenges in exploring and manipulating the human skin microbiome. Microbiome. 30 mai 2021;9:125.
BYOME LABS, France, Microbiome Respect Labeling Standards and Practices, Protocols and Internal Data
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The involvement or modification of the skin microbiome has become increasingly important in the pathogenesis of inflammatory skin diseases such as psoriasis.
Discover how age alters microbial composition, the skin barrier, and homeostasis. These changes directly influence barrier function and skin health.
A very comprehensive article on BYOME DERMA and our recent fundraising campaign.
