FDA/CFSAN FDA Consumer: Alpha Hydroxy Acids for Skin Care: Smooth
Sailing or Rough Seas?
U. S. Food and Drug Administration
March - April 1998; Revised May 1999
Alpha Hydroxy Acids for Skin Care
Smooth Sailing or Rough Seas?
by Paula Kurtzweil
Baby boomers and others who once sought the sun's rays with little thought of skin damage are now paying the price--billions of dollars annually for cosmetics containing alpha hydroxy acids (AHAs). Derived from fruit and milk sugars and served up in creams and lotions, AHAs attract customers with their supposed ability to reduce wrinkles, spots, and other signs of aging, sun-damaged skin. Some scientific evidence suggests they may work.
But are these products safe? Since 1989, the Food and Drug Administration has received more than 100 reports of adverse reactions in people using AHA products. Their complaints included severe redness, swelling (especially in the area of the eyes), burning, blistering, bleeding, rash, itching, and skin discoloration.
FDA believes reactions from AHAs are probably even more widespread. Past experience suggests that for every adverse reaction report the agency receives, the manufacturer receives 50 to 100. "This would translate into approximately 10,000 adverse reactions being received for AHA-containing products," says John Bailey, Ph.D., acting director of FDA's Office of Cosmetics and Colors.
Also, their relative newness (they've been widely available only since about 1992) means that their long-term effects are unknown. An industry-sponsored study found that people who use AHA products have greater sensitivity to sun, raising the specter of greater risk of photoaging and skin cancer.
"There are many unanswered questions in front of us," Bailey says. "AHAs are unlike anything else ever introduced onto the cosmetic market on such a wide scale. They are not your traditional cosmetics."
In spring 1997, the National Toxicology Program of the National Institute of Environmental Science accepted FDA's proposal to study AHA safety. While FDA awaits the results, expected by the year 2000, the agency is cautioning consumers to take extra care with AHA products: for example, avoiding the sun when possible, otherwise using adequate sun protection, and reporting adverse reactions immediately to doctors or FDA directly.
"These are very, very popular products," Bailey says. "Very little about the process restricts their sale. And it's a somewhat alarming idea to put acids on the skin. It raises obvious safety questions."
AHAs Are Everywhere
AHA cosmetics are believed to have derived from the "chemical peels" that dermatologists and plastic surgeons have used for years. The peels, typically trichloroacetic acid, phenol, resorcinol, and salicylic acid, help remove undesirable signs of skin aging, such as discoloration, roughness and wrinkling. The chemicals cause the skin to lose its outer layer, or peel off, revealing a fresher-looking layer of skin. Known as chemical exfoliation, the procedure is done in doctors' offices so that doctors can control the process and prevent deep skin burns from the highly acidic solutions.
Cosmetic manufacturers began to market similar but milder versions of these chemical peels containing AHAs for salon and at-home use around 1989. They quickly caught on, and by 1992, mass marketing had begun. Today, says Lisa Berger, a cosmetic sales manager for a Hecht Co. department store in Washington, D.C., "every [cosmetic company] has AHA products. There used to be only three product lines; now there are 20."
The AHAs used most often in cosmetics are glycolic acid and lactic acid, although there are others, and many are used in combination. Increasingly, says Zoe Draelos, M.D., a dermatologist in High Point, N.C., manufacturers are using poly-AHAs, which have larger molecules, and ingredients such as salicylic acid. According to Draelos, who consults for several large U.S. cosmetic companies, these products may produce less skin irritation.
Typically, AHA products sold to consumers have an AHA concentration of 10 percent or less. The concentration of AHA products used by trained cosmetologists may run between 20 and 30 percent, while those used by doctors can range from 50 to 70 percent.
Though sold to consumers mainly in face and body creams and lotions, AHAs also can be found to a lesser degree in other cosmetics, such as shampoos and cuticle softeners. Available everywhere, from discount pharmacies to fine department stores, the products typically range in price from a few dollars to as much as $60 a bottle.
Some in the cosmetic industry have suggested that AHA products are more than simple cosmetics, coining the term "cosmeceutical" to describe them instead.
Under the 1938 Federal Food, Drug, and Cosmetic Act, cosmetics are defined as "articles intended to be rubbed, poured, sprinkled, or sprayed on, introduced into, or otherwise applied to the human body or any part thereof for cleansing, beautifying, promoting attractiveness, or altering the appearance." Drugs are defined as products intended for treating or preventing disease and affecting the structure or any function of the body. They are subject to premarket review and approval; cosmetics are not.
"The term 'cosmeceutical' is not recognized by law," Bailey says. "These products, depending on their intended use, would be regulated either as cosmetics, drugs, or both as cosmetics and drugs."
FDA has a particular concern about AHAs because, unlike traditional cosmetics, AHAs seem capable of penetrating the skin barrier. In reviewing the limited data on AHAs, FDA concluded in a 1996 report that certain formulations of AHA products can affect the skin in a manner similar to that of chemical peels--that is, increasing cell turnover rate and decreasing the thickness of the outer skin. The effect depends on the product's pH level (a measure of its acidity), the AHA concentration, and the AHA vehicle cream, as well as how the product is used (for example, frequency of use and where on the skin it is applied).
An additional concern arose as FDA prepared its 1996 report on AHA safety: Some people who had reported adverse reactions cited increased sun sensitivity. In addition, one industry-sponsored study found that participants whose skin was exposed to 4 percent glycolic acid twice daily for 12 weeks developed minimal skin redness with 13 percent less ultraviolet (UV) radiation exposure than normal. Three participants developed minimal redness with 50 percent less UV exposure than normal.
Another study that looked at the effects of glycolic acid on production of sunburn cells (markers for UV-induced skin damage) found that people who received the AHA product in the presence of UV radiation experienced twice the cell damage in areas where the AHA had been applied than those who were treated with the non-AHA product.
FDA's concern is that people who are sensitive to sunlight may be particularly susceptible to UV rays, which can damage the skin and, over a long period, can cause skin cancer.
In 1997, the Cosmetic Ingredient Review Panel--the cosmetic industry's self-regulatory body for reviewing and addressing safety of cosmetic ingredients--concluded that the AHA's glycolic acid and lactic acid and their related chemical compounds are safe for use in products intended for consumer use when:
For AHA products used by trained cosmetologists, the Cosmetic Ingredient Review Panel concluded that formulations of glycolic acid and lactic acid at concentrations of 30 percent or less and a pH of 3.0 or greater intended for only "brief" use at one time followed by thorough rinsing and daily use of sun protection are safe.
- the AHA concentration is 10 percent or less
- the final product has a pH of 3.5 or greater (lower numbers indicate greater acidity)
- the final product is formulated in such a way that it protects the skin from increased sun sensitivity or its package directions tell consumers to use sunscreen products.
The panel's conclusions actually serve as guidelines for cosmetic manufacturers, Bailey says. "This means that each manufacturer of an AHA product should conduct appropriate testing on their products to measure whether or not the product increases the sensitivity of the user to UV radiation and, if so, should add sun protection to their product and warn consumers to take extra steps to protect themselves at all times."
Meanwhile, FDA continues to study AHA safety. Later this year, scientists with the National Toxicology Program and FDA will use hairless mice to study the effect of AHAs on the risk of cancer associated with sunlight and UV radiation. The study will run for about three years.
Depending on the outcome of FDA's investigation, Bailey says, the agency may or may not take action against AHA products. "The absence of action by FDA to date doesn't mean that there won't be any in the future."
Use with Care
Considering the questionable safety status, FDA and dermatologists advise consumers who use AHA products to follow these precautions:
If you have an adverse reaction, see a dermatologist. A dermatologist can tell you whether an adverse reaction is from the product or is an indication of an underlying disease, such as skin cancer. Dermatologists also can recommend appropriate skin-care products, and they will report your case, keeping your name confidential, to FDA's adverse reaction monitoring program.
- Always protect your skin before going out during the day. Use a sunscreen product with an SPF (Sun Protection Factor) of at least 15. Wear a hat with a brim of at least 4 inches (about 10 centimeters). Cover up with lightweight, loose-fitting, long-sleeved shirts and pants.
- Buy products with adequate label information: for example, a list of ingredients to see which AHA or other chemical acids are in the product; the name and address of the manufacturer or distributor, which can serve as the contact if a problem or question arises; and a statement about the product's AHA concentration and pH level. The first two pieces of information are mandatory; the third is optional. Consumers can call or write the manufacturer, however, to get information about a product's AHA concentration and pH level.
- Buy only products that comply with the Cosmetic Ingredient Review Panel's 1997 recommendations--that is, products with an AHA concentration of 10 percent or less and a pH of 3.5 or greater.
- Do a skin-sensitivity test on a patch of skin if you are a first-time user of any AHA product or are using a different brand or a product with a different concentration or pH than you are used to.
- Stop using the product immediately if you experience adverse reactions. Signs of adverse reactions include stinging, redness, itching, burning, pain, and bleeding or change in sun sensitivity. Even mild irritation is a sign that the product is causing damage, FDA's Bailey says, despite what the manufacturer may indicate on the product label. "Cosmetics shouldn't sting or cause irritation," he says.
You also can report your adverse reaction yourself to FDA. Reports can be made to local FDA offices, listed in the Blue Pages of the phone book or to FDA's Office of Consumer Affairs at 1-800-532-4440. Have the label and any other packaging information on hand. Be prepared to give the name of the product, the name and address of the manufacturer or distributor, and any identifiable product code numbers. Also be prepared to state where and when you bought the product, if you can remember, and whether you saw a doctor. "We'd like to know about it even if it's only a mild reaction," Bailey says.
Bailey adds that these precautions are important until AHAs' safety is better known. "We are told that AHAs are here to stay," he says. "But they are not reviewed for safety before they are put on the market. And we don't have enough information to say that they are safe."
Paula Kurtzweil is a member of FDA's public affairs staff.
Here are some ingredient terms that indicate a cosmetic contains alpha or beta hydroxy acids.
Alpha hydroxy acids:
Beta hydroxy acids:
- glycolic acid
- lactic acid
- glycolic acid + ammonium glycolate
- alpha-hydroxyethanoic acid + ammonium alpha-hydroxyethanoate
- alpha-hydroxyoctanoic acid
- alpha-hydroxycaprylic acid
- hydroxycaprylic acid
- mixed fruit acid
- triple fruit acid
- tri-alpha hydroxy fruit acids
- sugar cane extract
- alpha hydroxy and botanical complex
- L-alpha hydroxy acid
- glycomer in crosslinked fatty acids alpha nutrium
Alpha and beta hydroxy (BF) acids:
- salicylic acid
- beta hydroxybutanoic acid
- tropic acid
- trethocanic acid
Approved Treatments for Signs of Aging, Sun-Damaged Skin
These are the only products that have been studied for safety and effectiveness and approved by FDA for treating signs of sun-damaged or aging skin:
- Renova (tretinoin emollient cream). This vitamin A derivative, available by prescription only, is approved for reducing the appearance of fine wrinkles and mottled darkened spots and roughness of facial skin in people whose skin does not improve with regular skin care and use of sun protection. Renova does not eliminate wrinkles, repair sun-damaged skin, or restore skin to its healthier younger structure. Also, the safety of daily Renova use for longer than 48 weeks has not been established, and it should not be used by women who are pregnant or trying to become pregnant. Renova has not been studied in people 50 and older or in people with moderately or darkly pigmented skin.
- Carbon dioxide (CO2) and Erbium:YAG (Er:YAG) lasers. These medical devices are approved for treating wrinkles. The procedure requires removal of facial skin in a layer-by-layer manner. It is performed under anesthesia by a doctor in an outpatient surgical setting.
For More Information
FDA, Office of Consumer Affairs
Rockville, MD 20857
(10 a.m. to 4 p.m. Eastern time, Monday through Friday)
FDA's Office of Cosmetics and Colors
Automated telephone information line: 1-800-270-8869
(Recorded messages available 24 hours a day.)
FDA's World Wide Web site:
For more information about this article, contact FDA's Office of Public Affairs at 301-827-7130 or firstname.lastname@example.org.