Lactic acid is an alpha-hydroxy acid that exfoliates the skin by loosening bonds between corneocytes, promoting cell turnover, and acting as a humectant to improve hydration, texture, and tone. It is commonly used at concentrations ranging from low (hydration) to higher peel-strength formulations.
| Reported effect | How often | Notes |
|---|---|---|
Mild stinging or tingling on application | Common | Transient, often more noticeable at higher concentrations or on compromised skin. |
Skin dryness or flaking | Common | Result of accelerated exfoliation, especially when overused. |
Erythema (redness) | Common | Usually temporary; more pronounced with higher strengths. |
Increased photosensitivity | Common | AHAs heighten UV sensitivity; daily sunscreen is advised. |
Irritant contact dermatitis | Uncommon | Burning, itching, or persistent redness, often from overuse or high concentration. |
Post-inflammatory hyperpigmentation | Uncommon | More likely in darker skin tones following irritation. |
Chemical burn or blistering | Rare | Associated with high-concentration peels or prolonged contact. |
Allergic contact dermatitis | Very rare | True hypersensitivity to lactic acid is uncommon. |
Frequencies reflect typical cosmetic use reported in the literature, not a guarantee for your skin.
Peer-reviewed papers on this ingredient, via PubMed.