Beauty · 1 audit

pH Window — Verified Audits

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.

pH Window material texture

Audits using pH Window

SkinCeuticals C E Ferulic vs Maelove vs Timeless: L-Ascorbic Acid Concentration Audit

SkinCeuticals C E Ferulic ($182) uses 15% L-Ascorbic Acid at pH 2.5–3.5 — the proven photoprotection concentration. Maelove and Timeless achieve the same formulation for $26.

What is pH Window?

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.

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