Alpha Hydroxy Acids (AHAs)

Alpha hydroxy acids (AHAs) are a family of water-soluble acids used in skincare to exfoliate the surface of the skin. Common examples include glycolic acid, lactic acid, and mandelic acid, several of which are derived from sugars, milk, or fruit.

AHAs work by loosening the bonds that hold dead cells together in the outermost layer of the skin, encouraging those cells to shed more evenly. With regular use this can leave the surface smoother and more reflective, and is often used to address dullness, uneven texture, and the look of fine lines. Because they are water-soluble, AHAs act mainly on the skin surface rather than inside the pores.

AHAs are typically formulated in leave-on products at around 5–10% for home use, with lower strengths in rinse-off cleansers and higher strengths reserved for professional peels. Effectiveness depends heavily on the product's pH, which is why AHAs are usually formulated in a mildly acidic range.

AHAs can increase the skin's sensitivity to sunlight, so daily broad-spectrum sunscreen is generally advised during use. Introducing them gradually and avoiding layering with multiple other actives at once helps reduce the risk of irritation, stinging, or over-exfoliation.