Chances are you have had some personal experience with breakouts. Acne is the most common skin condition during puberty and beyond. The top ingredient used to treat acne is salicylic acid. It is effective in a variety of forms including face washes, overnight spot treatments, masks, toners, and lotions.
White willow (Salix alba) is a natural source of salicylic acid. According to ancient texts, early civilizations around the world used willow bark as a pain remedy and fever reducer. It was chewed or boiled into a tea. In the 1800s, the active extract of the bark was isolated and it was understood that salicin and salicylic acid were the anti-inflammatory compounds that made willow bark effective. Consumption of salicylic acid caused digestive issues, so later in the 19th century, chemists successfully produced acetylsalicylic acid to be gentler on the stomach, now commonly known as aspirin.
There is an FDA monograph for acne drug products including salicylic acid. This means that products with salicylic acid are regulated as over-the-counter (OTC) drugs if they make drug claims. According to the monograph, salicylic acid is generally recognized as safe at concentrations between 0.5 and 2.0 percent. Claims made for products with salicylic acid may include a variety of language about treating acne such as "clears up acne blemishes and allows skin to heal," "helps prevent development of new acne pimples," and "penetrates pores to control blackheads." If no specific claims are made about treating acne, products containing salicylic acid can be classified as cosmetics. For more information on FDA monographs and claims, refer to Cosmetic or Drug? Regulatory Basics and FDA Monographs.
How does salicylic acid work? The properties that make it so useful as an acne treatment include its drying effect on the skin, its antibacterial activity, and its effectiveness as an exfoliator. As an oil-soluble molecule, salicylic acid can penetrate the lipid membranes of the skin. It is a unique exfoliator because it sloughs off dead skin cells on the skin's surface and also penetrates into pores. This makes it especially successful at helping acne clear up quickly, decreasing inflammation, and preventing whiteheads and blackheads.
Salicylic acid can also be used as a treatment for other skin conditions. Scalp conditions like dandruff and seborrheic dermatitis are both caused by a slowing down of the process by which skin cells slough off. Salicylic acid treats these conditions with its properties as a exfoliator that can penetrate deep into the skin. In addition to scalp conditions, salicylic acid's drying properties also make it an effective treatment for wart removal.
Salicylic acid is capable of penetrating and breaking down lipids, causing moderate chemical burns of the skin at high concentrations. As mentioned above in the regulatory section, the FDA limits the over-the-counter concentration at 2.0% for acne treatments. Higher concentrations are allowed for chemical peels performed at a dermatologist's office or other functions such as wart removal pads or dandruff shampoos.
Some people, especially those with sensitive skin, may find salicylic acid to cause skin irritation, drying, peeling, or redness. For these people, using a less concentrated formula or a rinse-off product such as a face wash instead of a leave-on product such as a spot treatment may help alleviate the side effects. Since the ingredient will only be called out as an active ingredient on the product label if drug claims are being made, it is recommended that you check the entire ingredient list for salicylic acid before buying a product if you have a sensitivity.
I hope you found today's post informative and now know a bit more about the most common anti-acne ingredient - salicylic acid. As with any skincare product, it's best to experiment with different products until you find a brand or formula that works well for your skin. If you'd like to learn more about common cosmetic ingredients, check out Ingredients 101: Cosmetic Ingredients Broken Down by Source, Class, and Function. I've also covered other ingredients in the past including Sunscreen Active Ingredients and Retinol.
Do you have more questions on salicylic acid? Is there another common ingredient that you would like to learn more about? Let me know in the comments!