Skin Microbiome

What Is the Skin Microbiome?

The skin microbiome refers to the complex community of microorganisms — bacteria, fungi, viruses, and mites — that colonise the skin's surface and follicles. Far from being harmful, this ecosystem is a critical component of skin health. The microbiome outnumbers human skin cells and plays active roles in immune education, pathogen defence, barrier function, and even wound healing. The skin's microbiome is shaped by genetics, body site, age, diet, environment, and skincare practices.

Key Residents

In healthy skin, Staphylococcus epidermidis dominates many body sites and is a beneficial commensal — it produces antimicrobial peptides, competes with pathogens for resources, and reinforces the skin barrier. Cutibacterium acnes (in follicles) is normal at low levels but becomes problematic in the anaerobic environment of congested pores. The fungus Malassezia is universal on human skin and a key driver of seborrheic dermatitis and dandruff when populations overgrow.

Disruption and Dysbiosis

Skin microbiome imbalance (dysbiosis) is linked to eczema (atopic dermatitis, with S. aureus overgrowth), acne, rosacea, psoriasis, and seborrheic dermatitis. Over-washing, antibacterial soaps, excessive topical antibiotics, and harsh actives all reduce microbial diversity — creating ecological vacuums that opportunistic pathogens fill. Maintaining pH in the 4.5–5.5 range supports beneficial bacteria that prefer an acidic environment.

See Skin Microbiome Science and Acid Mantle.