While AHAs dissolve in water, salicylic acid dissolves in oil. That lets it reach into the sebum in the pores and break up the mix of oil and dead skin cells that can clog them. The result is clearer pores, fewer blackheads and a smoother surface.
Salicylic acid is also soothing and can tone down redness around blemishes. That is why it is often found in cleansers, toners and serums for oily, unsettled skin.
Skincare products usually use salicylic acid at low concentrations, up to 2 percent. Willow bark contains salicin, a naturally related compound, and is sometimes used as a gentler alternative.
How to use: Start with a few times a week and build up gradually. Salicylic acid can be drying, so follow with a light moisturiser. At first, avoid combining it with other strong acids or retinol on the same evening.
Good to know: Wear sun protection during the day. Names such as benzyl salicylate, ethylhexyl salicylate and homosalate are not salicylic acid, but fragrance and UV filters.
