Beauty
pH Window
Definition
The optimal hydrogen ion concentration range for a skincare active to function. L-Ascorbic Acid requires pH 2.5–3.5. Retinol requires pH 5–6. AHAs are most effective at pH 3–4.
Why it matters for dupe shopping
A serum containing 15% Vitamin C at pH 6 delivers zero antioxidant benefit — the pH deactivates the molecule. Duplixo tests or sources pH data for all beauty alternatives to verify actives are formulated in their effective range.