Lactic Acid (Alpha Hydroxy Acid (AHA)) - ph adjuster, exfoliant, humectant

INCI Name

Lactic Acid

Functions

3 Roles

Sustainability

8/10

What It Does

Lactic Acid is an alpha hydroxy acid naturally found in milk and produced commercially through bacterial fermentation of carbohydrates. It serves a dual role in cosmetics: as a pH adjuster to stabilize formulations and as a gentle chemical exfoliant that loosens the bonds between dead skin cells while providing mild hydration due to its humectant properties. Formulators favor it over glycolic acid for its larger molecular size, which provides effective exfoliation with less irritation, making it particularly suitable for sensitive skin formulations and products requiring precise pH control in the 3.5-4.0 range.

Optimizes formula stability

Ensures skin compatibility

Maximizes ingredient efficacy

Prevents irritation

Technical Properties

pH Range

2.0-5.0

Optimal working range

Ionic Charge

anionic

Molecular charge type

Viscosity Effect

neutral

Impact on formula thickness

Ingredient Compatibility

Known Interactions

RETINOLUse CautionpH Conflict

Retinol is destabilized by the low pH required for Lactic Acid efficacy (pH 3.5-4.0). Combined use increases irritation without proportional benefit. Use in separate products.

SALICYLIC ACIDUse CautionIrritation Risk

Combining AHA (Lactic) and BHA (Salicylic) increases exfoliation beyond what most skin can tolerate. Reduce concentrations if combining, or use in separate products.

Compatibility analysis powered by OpenMix — open-source formulation science