Salicylic acid occurs naturally in plants such as wintergreen leaves, willow bark and sweet birch bark, although it can also be manufactured in the laboratory. It is similar to the compound used in the manufacture of aspirin (acetylsalicylic acid), and it has anti-microbial and anti-fungal properties so it acts as a preservative in product formulations. It is also a beta-hydroxy acid (BHA), making it gentler and less irritating than AHAs. In fact, its keratolytic (keratin-dissolving) properties have been used by dermatologists for decades. This mild peeling effect helps reduce blocked pores whilst also smoothing the look and feel of the skin, so it is used in acne treatments, anti-ageing products, anti-dandruff care, bath and body care, and depilatory creams.

The name salicylic acid (2-Hydroxybenzoic acid) is derived from the Latin salix meaning “willow,” from the bark of which it can be obtained. It is a beta hydroxy acid (BHA) and is probably best known for its use in anti-acne treatments. Salicylic acid was also isolated from the herb meadowsweet (Filipendula ulmaria, Syn. Spiraea ulmaria). Salicylic acid is known for its ability to ease aches and pains and reduce fevers. These medicinal properties, particularly fever relief, have been known since ancient times, and it was used as an anti-inflammatory drug.

Salicylic acid is a skin exfoliant and has been used in conjunction with AHAs (alpha hydroxy acids) or alone for this purpose. It is a key ingredient for the treatment of acne, psoriasis, calluses, corns and warts. It works as a keratolytic by increasing the rate of skin cell turnover causing the cells of the epidermis to shed more readily, this helps prevent pores from clogging and allows for new cell growth. It has also been used in shampoos for the treatment of dandruff and has some skin-whitening properties. Excessive use can cause photosensitivity.

The Food and Drug Administration (FDA) has reviewed the safety of Salicylic Acid and permits its use as indirect food additives. Salicylic Acid is approved for use in Over-the-Counter (OTC) drug products. Salicylic acid is widely used as an FDA approved safe and effective acne drug product. It is also approved for use in OTC drugs for corn, callus and wart removal, as well as in antidandruff OTC drug products. The safety of Salicylic Acid and its salts and esters has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The CIR Expert Panel evaluated scientific data and concluded that Salicylic Acid was safe as used when formulated to avoid skin irritation and when formulated to avoid increasing the skin's sun sensitivity, or, when increased sun sensitivity would be expected, directions for use include the daily use of sun protection.

Function: Antidandruff/ hair conditioning/ keratolytic/ masking/ preservative/ skin conditioning.

CAS: 69-72-7

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Source: Dweck, Anthony. Handbook of Natural Ingredients (Dweck Books 4) . Dweck Data. Kindle Edition.

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