Salicylic acid has been used to treat ailments for thousands of years, dating to fifth century BC when Greek physician, Hippocrates, observed that a bitter powder extracted from willow bark could ease aches and pains and reduce fevers. This powder, also known as Salix, has been with us ever since.
Today, the preferred method for commercial use is to produce salicylic acid synthetically. It can be prepared, for example, by the hydrolysis of aspirin (acetylsalicylic acid) or, in the case of methyl salicylate (oil of wintergreen), by the introduction of a strong acid, such as methanol. Salicylic acid, therefore, is a component of aspirin, not aspirin itself. Additional natural sources include unripe fruits and vegetables, notably blackberries, blueberries, green peppers and mushrooms.
As the Greeks discovered, salicylic acid is good for what ails you. The key ingredient is acetylsalicylic acid (ASA), it’s what we reach for when we reach for aspirin. As a salicylate drug, ASA works as an analgesic to relieve pain, as an antipyretic to reduce fever, and also as an anti-inflammatory drug. Long-term, low doses are also prescribed to prevent heart attacks and strokes in high-risk patients.
In cosmetics, beta hydroxy acid refers specifically to salicylic acid, which is used in a variety of products to treat skin conditions ranging from psoriasis to acne. Alpha hydroxy acids, such as lactic, malic and citric acids, boast similar capabilities but lack the anti-inflammatory properties of beta hydroxy acids. Salicylic acid creams and lotions often include skin softening agents, such as urea. In combination, these ingredients help soften and remove psoriasis scales. In the treatment of acne, salicylic acid’s exfoliating action causes skin cells to shed more readily, opens clogged pores and neutralizes bacteria. This mechanism also helps to clear blackheads and whiteheads.
Salicylic acid and benzoic acid, together, treat skin irritation and inflammation caused by burns, insect bites and fungal infections. Warts also respond well to salicylic treatment, where it is applied directly or via adhesive pads to dissolve the wart. Creams and lotions typically contain one half to six percent salicylic acid by volume, while 26 percent or more is common in topical products.
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