Journal September 26, 2026 3 min read

How does the skin microbiome work?

The skin microbiome is the community of microorganisms inhabiting the skin. This page outlines research into its role in barrier function, inflammation, and disease, based on registered clinical studies.

peptides-pro Editorial

The skin microbiome refers to the diverse community of bacteria, fungi, viruses, and other microorganisms that reside on the skin. It is also known as the cutaneous microbiota or skin flora. While the evidence block does not provide a formal sequence, formula, or molecular weight for the microbiome as a whole, research has identified specific microbial components and their interactions with the host. For example, vernix caseosa, a naturally occurring substance covering newborn skin, is implicated in skin-barrier integrity and microbiome development during early life [1]. The pathway or receptor family most central to this work involves T helper 2 (Th2)-related inflammation and antimicrobial peptide expression, as seen in studies of rosacea and lymphedema [2][4].

Research into the skin microbiome spans multiple domains, including barrier function, inflammatory signaling, and responses to topical agents. Studies are investigating how the microbiome changes in conditions such as atopic dermatitis, rosacea, and aging skin, and how interventions like moisturizers or ivermectin may alter microbial communities and associated biomarkers [1][3][4].

Research Studies

Vernix caseosa and atopic dermatitis prevention in newborns

A clinical trial is investigating the retention of vernix caseosa in newborns for the primary prevention of atopic dermatitis (AD), also known as eczema. AD is a chronic inflammatory skin disease that usually begins in infancy and affects up to one in five children worldwide. The study focuses on genetic and environmental factors related to skin-barrier integrity and the skin microbiome during early life, with the goal of preventing AD before it starts [1].

Skin barrier function and inflammation in aging: the BIA study

A randomized, investigator-blinded, self-controlled pilot study is examining the physiologic response to topical moisturizers among older adults with dry skin. The hypothesis is that skin barrier decline contributes to chronic inflammation, and that restoring the barrier with moisturizers can reduce serum biomarkers of inflammation. Secondary objectives include determining changes in serum inflammation, skin barrier function, and the skin microbiome in response to moisturizers [3].

Topical ivermectin and rosacea-specific inflammation

A 16-week open-label study at the University of California, San Diego, is assessing the effects of topical ivermectin 1% cream on protease and antimicrobial peptide expression and on the skin microbiome in rosacea. The study measures serine protease activity, cathelicidin levels, and the skin microbiome before and after 12 weeks of daily ivermectin application, with monthly scoring of facial redness and papules [4].

Biological profile of lymphedema: inflammatory and lymphatic markers

An observational, cross-sectional study aims to characterize the biological profile of primary and secondary lymphedema across five domains: T helper 2 (Th2)-related inflammation, endothelial activation, metabolic dysfunction, lymphatic biology, and tissue fibrosis. While traditionally considered a disorder of impaired lymphatic drainage, increasing evidence suggests that lymphedema involves chronic inflammation, endothelial dysfunction, metabolic alterations, abnormal lymphatic signaling, adipose tissue accumulation, and progressive tissue fibrosis [2].

Comparative overview of study designs

The table below summarizes key features of the registered studies discussed above.

Study	Condition	Design	Primary outcome
Vernix caseosa retention [1]	Atopic dermatitis	Clinical trial	Primary prevention of AD
BIA study [3]	Aging skin, dry skin	Randomized, investigator-blinded, self-controlled pilot	Feasibility for larger trial
Topical ivermectin [4]	Rosacea	Open-label, 16-week	Protease and antimicrobial peptide expression, skin microbiome
Lymphedema profile [2]	Primary and secondary lymphedema	Observational, cross-sectional	Biological markers across five domains

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