Lactic acid is an alpha-hydroxy acid derived from milk that exfoliates by loosening bonds between surface skin cells and also acts as a humectant to attract moisture. It is used to improve skin texture, tone, hydration, and signs of photoaging.
| Reported effect | How often | Notes |
|---|---|---|
| Stinging or tingling on application | Common | Transient, more pronounced at higher concentrations or lower pH |
| Mild erythema (redness) | Common | Usually subsides shortly after application |
| Dryness or flaking | Common | Related to increased exfoliation, especially early in use |
| Increased photosensitivity | Common | Sunscreen recommended during use |
| Irritant contact dermatitis | Uncommon | More likely with overuse or high concentrations |
| Post-inflammatory hyperpigmentation | Uncommon | Chiefly in darker skin types or with irritation/peels |
| Chemical burn | Rare | Associated with high-strength peels or prolonged contact |
| Allergic contact dermatitis | Rare | True sensitization is infrequent |
Frequencies reflect typical cosmetic use reported in the literature, not a guarantee for your skin.