Stratum corneum pH (4. 5) maintains barrier integrity, antimicrobial defense, and enzyme kinetics. Alkaline cleansers (pH 9–10) disrupt this acid mantle for up to 6 hours.
Use pH-balanced cleansers (4.5–6.5). For AHA/BHA exfoliants, verify pH on label — pH > 4 substantially reduces efficacy regardless of concentration.
If you're targeting barrier dysfunction, this research supports adding glycolic acid to your PM routine.
If you're targeting barrier dysfunction, this research supports adding salicylic acid to your AM/PM routine.
Translated from this study's findings, not a personal prescription. Pair with your existing protocol and your practitioner's guidance.
Stratum corneum pH 4.5–5.5 is critical for barrier integrity, antimicrobial defense, and serine protease regulation. Alkaline cleansers (pH 9–10) disrupt acid mantle for up to 6h. Acid pH cleansers preserve barrier. Formulation pH determines active bioavailability: AHAs pH 3–4, vitamin C pH <3.5, retinoids pH 5–6.
Stratum corneum pH (4.5–5.5) maintains barrier integrity, antimicrobial defense, and enzyme kinetics. Alkaline cleansers (pH 9–10) disrupt this acid mantle for up to 6 hours. Acid pH cleansers (pH 4.5–5.5) preserve barrier function. AHA and BHA exfoliants require pH 3–4 for free-acid bioavailability. Vitamin C requires pH < 3.5.
Original source →Niacinamide is one of the most well-researched skincare ingredients. Studies show it reduces pore appearance, fades dark spots, and strengthens your skin barrier — all backed by clinical trials.
Sensitive skin is real, not just a label. It's caused by overactive nerve receptors, mild barrier damage, and reactive inflammation. The fix is fewer products, gentler ingredients, and patience.
Skin cycling alternates strong actives (acids, retinoids) with recovery nights so your barrier can repair. The biological rationale is solid — acute barrier disruption recovers in 48–72 hours — and it works in practice for sensitive users.
This information is for educational purposes only and is not medical advice. Individual results vary. Consult a qualified dermatologist or healthcare professional for medical concerns. Full disclaimer →