Salicylic acid is a beta-hydroxy acid and is often used to treat skin conditions such as acne, body acne, psoriasis, dandruff, seborrhoeic dermatitis, warts and calluses. This over-the-counter skin care treatment is frequently derived from natural sources (the bark of the willow tree) and its' chemical structure is similar (but not identical) to that of aspirin. Salicylic acid can be chemically synthesized from the amino acid phenylalanine. Salicylic acid has been used throughout history for pain relief and to reduce fevers and is now widely used as a major skin care ingredient.
Salicylic acid causes skin cells to shed more rapidly (exfoliation), preventing skin pores from clogging up. Salicylic acid penetrates deep into the skin pores and helps clear out the trapped sebaceous oil that builds up around hair follicles. This will help to prevent bacteria from growing in this mixture of excess skin and oil, which could develop into red inflamed blemishes. Salicylic acid has been medically proven to help decrease inflammation of newly formed blemishes (including whiteheads and blackheads).
Since salicylic acid also breaks down the skin protein keratin, excess (thickened) skin can easily be removed after treating with salicylic acid. Salicylic acid is available in many different strengths (from 0.5% to 30%) and many different forms for use. Topical treatments containing salicylic acid may be in the form of creams, lotions, ointments, shampoos, body washes, pads, gels and band-aids. Please note that the higher concentrations of salicylic acid are used for treating conditions such as calluses and warts and that acne on the face is treated with much lower concentrations of salicylic acid. Salicylic acid cannot be used to treat rosacea.