Lactic Acid
Lactic acid is an alpha-hydroxy acid (AHA) and the second most researched AHA after glycolic acid. It works by gently lifting dead skin cells from the skin's surface to reveal fresher, smoother skin underneath. Its larger molecular size compared to glycolic acid means it penetrates the skin less effectively, making it more gentle. It also functions as a humectant and buffering agent, as listed in official CosIng data.
Lactic acid exfoliates the skin to improve texture and complexion, and has notable moisturizing properties that can help treat dry skin. At higher concentrations (10% and above) and appropriate pH (3–4), studies show it can improve skin firmness, thickness, and reduce the appearance of wrinkles. The L-lactic acid form specifically demonstrates effective results with lower irritation potential compared to the D-form.
Increases photosensitivity — sunscreen use is strongly recommended when using AHA-containing products. Effectiveness is highly dependent on both concentration and pH; products with unknown concentration or pH may not deliver expected results. May cause stinging or burning, particularly at higher concentrations or lower pH values.
