Ingredient · Alpha-hydroxy Acid · Lactic
P. 10 · BRIEFThe forgiving AHA. Larger molecule, slower penetration, lower irritation curve. It is also a natural humectant, which is why it leaves skin feeling more hydrated than glycolic. The right exfoliant for sensitive skin and the right starting point for AHA-curious users.
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Lactic acid is an alpha-hydroxy acid produced by lactobacilli during sugar fermentation. It is also one of the components your own skin makes as part of natural moisturising factor (NMF), which is why a leave-on lactic serum simultaneously exfoliates and hydrates — a combination glycolic acid cannot match. The molecule is roughly twice the size of glycolic, so it penetrates more slowly and irritates less.
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On exfoliation
Loosens corneocyte adhesion at the upper stratum corneum. Slower depth than glycolic.
On hydration
Acts as a humectant; component of native NMF. Net moisture gain after use.
On pigment
Mild tyrosinase inhibition at higher concentrations. Adjunctive for PIH and dullness.
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Nightly is fine. The default for sensitive skin.
Hydration plus exfoliation. The sweet spot for most.
More turnover, still tolerable. Cap here for home use.
In-clinic peels. Not a home product.
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Premium reference. 5% in a polished vehicle, comfortable nightly.
Honest dose, basic vehicle. Still the best value entry.
Indian-market, ceramide base. Good for combination skin.
Higher dose without losing comfort. Good vehicle work.
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Lactic. Same exfoliation mechanism, gentler curve, hydration bonus. Move to glycolic only if lactic plateaus and your barrier is comfortable.
Lactic is a humectant as well as an exfoliant — one of the few acids that net adds moisture. That's the molecule's signature.
Most people can. Start three nights a week, build over four weeks. If your retinoid is also nightly, alternate them.
Yes, at standard cosmetic concentrations. One of the few well-studied actives that remains usable through pregnancy.
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— Cross-references
Concerns it treats