The acid mantle
Healthy skin has a slightly acidic surface pH of 4.5-5.5. This is called the acid mantle, and it supports the enzymes that maintain the barrier while inhibiting harmful bacteria.
When pH goes wrong
- High pH (alkaline): soap-based cleansers strip the acid mantle, leaving skin tight and vulnerable. The barrier takes hours to recover.
- Low pH (acidic): some actives (like L-ascorbic acid at pH 3.5) are intentionally acidic for efficacy, but prolonged exposure can irritate.
Choosing pH-appropriate products
- Cleansers should be pH 5-7 (avoid traditional soap)
- Vitamin C (L-AA) works best at pH 3-4
- Niacinamide and hyaluronic acid work across a wide pH range
This is why Coyglow formulates its Gentle Enzyme Cleanser at skin-neutral pH.