The Effects of Salicylic Acid

Salicylic acid---chemically, C6H4OHCOOH---is a phytohormone compound found in the bark of willow and birch trees. It is best known as a topical treatment for acne and other skin disorders. It is also the natural form of the semisynthetic compound acetylsalicylic acid, better known as aspirin. Whether used topically or internally, salicylic acid is associated with numerous medicinal effects and some potential dangers.

Internal Effects

"Ordinary" salicylic acid is rarely taken internally because it has been largely replaced by aspirin, one of its pharmaceutical derivatives. When it is taken internally, it has nearly identical effects (and side effects) of its more popular, pharmaceutical counterpart. Though it has many of the same risks and side effects, "regular" salicylic acid is preferred by some naturopaths because it can be derived from natural materials.
Internal use of salicylic acid yields results that are similar to aspirin. Salicylic acid is a pain reliever, antispasmodic, fever reducer and mild antibiotic. It also has some anticoagulant effects and can impair blood clotting, so it is considered to be unsafe for internal use in people with bleeding disorders and women who are pregnant.

A Peeling Agent

Salicylic acid is almost always used externally, as a treatment for skin disorders. Its primary topical use is to help the body remove injured tissue because it acts as keratolytic, or peeling agent. By shuffling off the top layer of skin, repeated treatments with salicylic acid can eliminate pimples, warts, psoriasis and other blemishes, revealing healthier skin beneath.
Because it is slightly irritating and causes the skin to gently peel, salicylic acid should not be used on sensitive areas, such as the eyelids, lips, genitals, or any area that may be sunburned or chapped. Misapplication or overapplication can cause the area to become irritated, inflamed, or scaley, and may cause a burning sensation.

How It Works

When salicylic acid is applied to acne or pimples, its aspirin-like effects immediately cause the area to become less inflamed, causing near-immediate reduction in pain, redness and swelling. Its gentle peeling effects also allow the blemishes to "open" and drain, enabling the pimples to shrink. Over time, treatment with salicylic acid can completely eliminate pimples.
Other skin conditions, such as psoriasis, corns, callouses and warts, can also be treated effectively using salicylic acid. In these cases, the compound works to condition, moisturize and soften the affected area, while also enabling gentle ex foliation. Depending on the thickness and severity of the disfigured area, it may take several days, weeks or even months for the treatment to eliminate problems of this type.

Side Effects

Side effects from salicylic acid are somewhat common, but generally mild and temporary. Salicylic acid may cause a sensation of burning or stinging shortly after being applied to the skin, and this feeling usually passes within minutes without treatment. Peeling of the skin can also occur, especially if the salicylic acid is over-applied or applied to sensitive skin.
Very rarely, a serious allergic reaction to salicylic acid may occur. Because it is chemically similar, people who are allergic to aspirin or other salicylates should exercise caution when using salicylic acid, as they may be more at risk of experiencing an allergic reaction from topical use. Symptoms include rapid heartbeat, weakness, vomiting and diarrhea. An allergic reaction to any medication would require prompt medical attention.

Maximizing Benefits

People using salicylic acid can minimize risks and maximize benefits by using it only according to a physician's recommendations or the drug manufacturers' guidelines. Over-application of salicylic acid will not enhance its effects; however, it may increase the likelihood of experiencing unwanted peeling or irritation in the affected area.
Salicylic acid is most effective if it is used on freshly washed skin, since this eliminates the oil-barrier between the medicine and the area it is applied to. If needed, a moisturizer can be applied one to two hours after the application of salicylic acid. Unless otherwise directed by your physician, avoid applying the medicine to large parts of your body, and discontinue use of the product when your symptoms have been eliminated.