What is salicylic acid?
Referred to as beta hydroxy acid (BHA), it is a multifunctional ingredient that addresses many of the systemic causes of blemishes (Source: Seminars in Dermatology, December 1990, pages 305–308). For decades dermatologists have been prescribing salicylic acid as an exceedingly effective keratolytic (exfoliant), but it also is an anti-irritant This is because salicylic acid is a derivative of aspirin (both are salicylates—aspirin’s technical name is acetylsalicylic acid), and so it also functions as an anti-inflammatory (Sources: Archives of Internal Medicine, July 2002, pages 1531–1532; Annals of Dermatology and Venereology, January 2002, pages 137–142; Archives of Dermatology, November 2000, pages 1390–1395; and Pain, January 1996, pages 71–82).
Salicylic acid and acne
Another notable aspect of salicylic acid for treating breakouts is that it has antimicrobial properties (Sources: Preservatives for Cosmetics, 1996, by David Steinberg, Allured Publishing; and Health Canada Monograph Category IV, Antiseptic Cleansers, www.hc-sc.gc.ca/english/). BHA has the ability to penetrate into the pore (AHAs do not), and thus can exfoliate inside the pore as well as on the surface of the skin, which makes it effective for reducing blemishes, including blackheads and whiteheads.
It is also well documented that salicylic acid can improve skin thickness, barrier functions, and collagen production (Sources: Dermatology, 1999, volume 199, number 1, pages 50–53; and Toxicology and Applied Pharmacology, volume 175, issue 1, pages 76–82). As an exfoliant, in concentrations of 8% to 12%, it is effective in wart-remover medications. In concentrations of 0.5% to 2%, it is far more gentle, and, much like AHAs, can exfoliate the surface of skin.