You wash your face every day. You apply serums. You use SPF. But there is an entire ecosystem on your skin that most skincare advice completely ignores — and it may be the most important factor in determining whether your skin is clear, glowing, and healthy, or acne-prone, dull, and reactive.
This ecosystem is called the skin microbiome. And understanding it is the key to understanding why some skincare works and why most of it does not.
What Exactly is the Skin Microbiome?
Your skin hosts approximately 1.8 million microorganisms per square centimetre. These include bacteria, fungi, viruses, and mites — and the vast majority of them are not harmful. In fact, most of them are essential.
Just like your gut microbiome (the bacterial ecosystem in your digestive system), your skin microbiome:
• Protects against harmful pathogens by competing for space and resources
• Maintains your skin's slightly acidic pH (4.5–5.5) — the pH at which your skin barrier functions optimally
• Trains and regulates your skin's immune response — determining what triggers inflammation and what does not
• Produces antimicrobial compounds that neutralise bacteria like Staphylococcus aureus and Cutibacterium acnes (the bacteria primarily responsible for acne)
• Supports the production of ceramides — the lipid molecules that hold your skin's barrier together
What Disrupts the Skin Microbiome?
Modern life in urban India is particularly hostile to the skin microbiome:
• Antibacterial soaps and harsh cleansers: kill both harmful AND beneficial bacteria indiscriminately
• Hard water: the high calcium and magnesium content disrupts skin pH and kills beneficial bacteria
• Pollution: fine particulate matter creates oxidative stress and disrupts the microbial ecosystem
• Antibiotic skincare (clindamycin, erythromycin): kills acne bacteria but also decimates protective species
• Over-exfoliation: removing the skin's surface layer also removes the bacterial communities living there
• Stress: cortisol directly impacts the skin microbiome's composition and diversity
What Happens When the Microbiome is Disrupted
When your skin microbiome loses its diversity and balance, the consequences show up on your skin:
• Acne: C. acnes bacteria overgrow when competing species are depleted
• Sensitivity and redness: the immune regulation provided by beneficial bacteria is lost
• Eczema and rosacea flare-ups: both are strongly linked to microbiome disruption
• Persistent dark spots: chronic inflammation (a result of microbiome imbalance) drives excess melanin production
• Premature ageing: beneficial bacteria help maintain skin's collagen production and antioxidant defence
How to Support Your Skin Microbiome
This is where postbiotic skincare enters. Rub It In Serum by Sonnet Wellness uses Lactobacillus Ferment Lysate — the concentrated, stable by-products of Lactobacillus bacteria fermentation. These postbiotics:
• Feed and support the growth of beneficial bacteria already on your skin
• Produce the antimicrobial compounds that the microbiome uses to defend itself
• Reduce the chronic inflammatory signalling that results from microbial imbalance
• Restore the skin's pH conditions that allow beneficial bacteria to thrive
Supporting your skin microbiome is not a trend. It is the next evolution of skincare science — and it is what India's grandmothers practised with curd for generations.
