Alpha hydroxy acids are a group of natural acids found in foods. Alpha hydroxy acids include citric acid (found in citrus fruits), glycolic acid (found in sugar cane), lactic acid (found in sour milk), malic acid (found in apples), tartaric acid (found in grapes), and others.
Some people take malic acid by mouth with magnesium for treating pain and tenderness associated with fibromyalgia.
Various alpha hydroxy acids are applied to the skin (used topically) for moisturizing and removing dead skin cells, for treating acne and improving the appearance of acne scars, for improving the appearance of photo-aged skin, and firming and smoothing skin.
Alpha hydroxy acids are also used topically to treat extremely dry skin (xerosis), an inherited disease marked by dry, scaly skin (ichthyosis), and a condition that causes darkening of the skin (melasma). When this condition develops in pregnant women, it is sometimes called “the mask of pregnancy.”
Not all cosmetics that contain alpha hydroxy acid have the concentration information on the label. For safety’s sake, it’s best to use products that identify the concentration of active ingredients.
How does it work?
Alpha hydroxy acids seem to work by removing the top layers of dead skin cells. They can also increase the thickness of deeper layers of skin, promoting firmness.
- · Treating sun damage when applied to the skin in a cream or lotion, but alpha hydroxy skin peels do not seem to work for this use.
- · Treating dry skin when applied to the skin in a cream or lotion.
- · Acne when applied to the skin in a cream or lotion.
- · Acne scars when applied to the skin in a facial peel or lotion. Applying glycolic acid, an alpha hydroxy acid, as a facial peel or lotion seems to improve the appearance of acne scars. Applying 70% glycolic acid in a series of peels seems to work better than using 15% glycolic acid lotion daily. However, 15% glycolic acid lotion seems to be moderately effective in people who cannot tolerate facial peels.
- · Reducing pain and tenderness caused by fibromyalgia when a specific alpha hydroxy acid, called malic acid, is used in combination with magnesium.
- · Reducing the pigmentation associated with a skin disorder called melasma. Applying 10% glycolic acid as a lotion for 2 weeks followed by a facial peeling program using 50% glycolic acid every month for 3 consecutive months seems to reduce unwanted skin coloration in people with two of the three types of melasma, epidermal-type and mixed-type melasma. However, glycolic acid facial peels don’t seem to work for the third type of melasma, dermal-type melasma.
Alpha hydroxy acids at a concentration of 10% or less as a lotion or cream are LIKELY SAFE for most people when applied to the skin appropriately and as directed. In some people, alpha hydroxy acids can make the skin extra sensitive to sunlight. Be sure to use a sunscreen while using alpha hydroxy acid products.
Alpha hydroxy acids can also cause mild skin irritation, redness, swelling, itching, and skin discoloration.
Facial peels, lotions, and creams with a concentration greater than 10% should only be used under the supervision of a dermatologist. Facial peels can cause moderate to severe skin irritation, redness, and burning. Facial peels left on the skin for periods longer than recommended can cause severe burns to the skin.
When taken by mouth, the alpha hydroxy acid called malic acid is POSSIBLY SAFE when used short-term. Some people can have side effects including diarrhea, nausea, and general stomach discomfort.
Special Precautions & Warnings:
Pregnancy and breast-feeding: Alpha hydroxy creams at a concentration of 10% or less are LIKELY SAFE when applied to the skin during pregnancy and breast-feeding. But don’t take malic acid (the form of alpha hydroxy acids that is generally taken by mouth). Not enough is known about the safety of malic acid during pregnancy and breast-feeding.
Sensitive skin: Alpha hydroxy acids can worsen skin conditions by causing skin irritation and removal of the top layer of skin cells.