What is AHA vs BHA?

AHAs (Alpha Hydroxy Acids — glycolic, lactic, mandelic, tartaric) are water-soluble and exfoliate on the skin surface. Best for dullness, fine lines, and dry skin texture. BHAs (Beta Hydroxy Acids — salicylic acid mainly) are oil-soluble and penetrate INTO sebaceous follicles, clearing them from inside. Best for acne, pores, and oily/combination skin. PHAs (Polyhydroxy Acids — gluconolactone, lactobionic) are larger AHA cousins that stay at the surface and don't penetrate — gentlest option, best for sensitive or rosacea-prone skin.