Salicylic acid, a beta hydroxy acid, is an exfoliant that is either derived from the botanical willow bark or created synthetically. The structure of beta hydroxy acids are important because they are oil soluble; they can penetrate more effectively into the pores of the skin. Once the beta hydroxy acid has penetrated the skin, the acid portion works to dissolve the glue that holds skin cells together. Alpha hydroxy acids, on the other hand, are water soluble, so they work primarily to exfoliate the surface of the skin.

Salicylic acid is excellent at deeply exfoliating the skin, as well as treating and preventing acne and clogged pores. Products that contain salicylic acid – especially when mixed with alpha hydroxy acids, like glycolic or lactic acids – are ideal for treating ingrown hairs caused by hair removal. Salicylic acid is also anti-inflammatory, so it is beneficial for calming redness and irritation post-waxing or hair removal. Furthermore, its cellular-loosening properties help to shed skin cells and reduce dead skin buildup and inflammation, keeping ingrown hairs from forming at all.

Salicylic acid works by sloughing the skin. When the acid is regularly applied to the skin, the uppermost layer of skin swells, softens, and peels, effectively removing dead skin cells. Salicylic acid also prevents the pores from clogging by slowing the shedding of dead skin cells inside the follicle, which prevents acne. It has also been shown to be highly effective at breaking down the formation of whiteheads and blackheads. These types of acne are notoriously difficult to treat because they form within the pores, as opposed to the surface of the skin.

Salicylic acid can also be used to treat psoriasis. Because salicylic acid serves as a sloughing and softening agent, it will cause the outermost layer of skin to shed, causing the scales and rough patches to soften.

If clients have skin concerns, such as ingrown hairs due to hair removal, it is imperative that they work with a homecare treatment to help prevent and eliminate blemishes. Salicylic acid functions best when it is used in a serum with alpha hydroxy acids. Adding a serum with salicylic acid to clients' homecare regimen is a quick way to boost sales and give their skin the youthful, dewy appearance it has been missing.