Alpha Hydroxy Acids

• Overview
• Uses
• Side Effects
• Precautions
• Dosing

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 insugarcane), 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 treatingpainand tenderness associated withfibromyalgia.

Various alpha hydroxy acids are applied to the skin (used topically) for moisturizing and removing dead skin cells, for treatingacneand improving the appearance ofacnescars, for improving the appearance of photo-aged skin, and firming and smoothing skin.

Alpha hydroxy acids are also used topically to treat extremelydry skin(xerosis), aninherited diseasemarked by dry, scaly skin (ichthyosis), and a condition that causes darkening of the skin (melasma). When this condition develops inpregnantwomen, it is sometimes called “themask of pregnancy.”

Not allcosmeticsthat 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?

阿尔法羟基酸似乎工作通过消除top layers of dead skin cells. They can also increase the thickness of deeper layers of skin, promoting firmness.

Likely Effective for...

• 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.
• Treatingdry skinwhen applied to the skin in a cream or lotion.

Possibly Effective for...

• Acnewhen applied to the skin in a cream or lotion.
• Acnescars 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.
• Reducingpainand tenderness caused byfibromyalgiawhen a specific alpha hydroxy acid, called malic acid, is used in combination with magnesium.
• Reducing the pigmentation associated with a skin disorder calledmelasma. 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.

Insufficient Evidence to Rate Effectiveness for...

• Treating aninheritedskin disorder that causes dry, scaly skin (ichthyosis).
• Other conditions.

More evidence is needed to rate alpha hydroxy acids for these uses.

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).

Alpha hydroxy acids at a concentration of 10% or less as a lotion or cream areLIKELY SAFEfor 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 asunscreenwhile 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 severeburnsto the skin.

When taken by mouth, the alpha hydroxy acid called malic acid isPOSSIBLY SAFEwhen used short-term. Some people can have side effects includingdiarrhea,nausea, and general stomach discomfort.

Pregnancyand breast-feeding: Alpha hydroxy creams at a concentration of 10% or less areLIKELY SAFEwhen applied to the skin duringpregnancyand 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 worsenskin conditionsby causing skin irritation and removal of the top layer of skin cells.

The following doses have been studied in scientific research:

APPLIED TO THE SKIN:

• For treating skin wrinkled and aged by sunlight: Alpha hydroxy acid products containing lactic acid, tartaric acid, gluconolactone, or glycolic acid (GA) in 8% concentration are used. The alpha hydroxy acid gluconolactone has also been used in a 14% solution. These products are usually applied to the skin twice daily.
• 改善痤疮疤痕的外观:乙二醇ic acid (GA) facial peels are used. Peels of increasing strength of 20%, 35%, 50%, and 70% are applied every two weeks. Peels are applied first for 2 minutes and then for a longer time (up to 4-5 minutes) before applying the next stronger solution. Completing the series at least 6 times is usually needed before skin looks better. People who do not like facial peels often use 15% GA lotion daily long-term instead.
• For lightening brown patches due to a condition called melasma: a 10% lotion of the glycolic acid (GA) is applied with a sunscreen to facial skin nightly for 2 weeks. Then a peeling program is done monthly for 3 months in a row. The peeling program features a 50% GA peel applied three times to the face and left on for a period of 2-5 minutes each time (first peel 2 minutes, second peel 4 minutes, and third peel 5 minutes).