Salicylic Acid
Salicylic acid (SA) is a beta-hydroxy acid (BHA) that is lipid-soluble, allowing it to penetrate into pores and shed dead skin cells from within. It is chemically similar to aspirin and carries anti-inflammatory properties alongside its keratolytic action. For at-home use, effective concentrations range from 0.5–2% (2% being the EU maximum), while professional peels can reach 20–30%. Its official CosIng functions include antidandruff, hair conditioning, keratolytic, masking, preservative, and skin conditioning.
Salicylic acid exfoliates both the skin surface and inside pores, making it particularly effective against blackheads, whiteheads, and large pores. It acts as a potent anti-inflammatory agent, beneficial for acne and rosacea. Studies at 2% show it does not increase sun sensitivity and may even have photoprotective effects.
For inflamed acne, SA alone is only moderately effective and works best when combined with an antibacterial agent such as benzoyl peroxide or azelaic acid. Professional-strength peels (20–30%) should not be used at home. EU regulations cap at-home use at 2% maximum concentration.
