Lactic acid is one of the most popular alpha hydroxy acids (AHAs) in skin care today, marketed as a powerful ingredient that helps reduce acne breakouts and the appearance of wrinkles and other signs of aging.
Lactic acid is actually more gentle than glycolic acid—another popular AHA—but there are still some dangers when using it. Personally, I think all AHAs are too harsh for skin, and prefer using natural alternatives to gain the same benefits.
Lactic acid may exfoliate your skin, but over time, it could lead to increased aging due to sun damage.
What is Lactic Acid?
Lactic acid is a natural acid derived from milk, fruit, vegetables and other plants. It's found in over-the-counter skin care products used for anti-aging, and is also used in chemical peels. With a reputation for being gentler and less irritating than glycolic acid, it also hydrates, increases natural barrier lipids in the outer layer of skin, and lightens and brightens the look of skin for those with discoloration.
Mainly, however, lactic acids and other AHAs are used to exfoliate.
Is it Safe?
In 2002, the Los Angeles Times ran a feature on AHAs, noting that the public was failing to protect their skin from the sun when using them. AHAs slough off the outer layer of skin, which makes them effective exfoliators, but in the process, they leave skin more vulnerable to the damaging effects of UV rays. That means without the right protection, they can not only lead to sunburn, but may actually make skin worse over time because of the lasting damage of sun exposure. Even worse, if skin burns, it's more at risk for skin cancer down the road.
According to the LA Times, AHAs can increase the possibility of sunburn and sun sensitivity for up to a week after they've been applied. Most users don't realize that, and may use sunscreen for a day or two, but then forget to maintain protection. Even intermittent sun exposure can damage sensitive skin.
The FDA reported that they received a total of 114 adverse dermatologic experience reports linked to AHA-containing skin care products between 1992 and 2004. The number was likely much higher as many don't bother to report their experiences. Problems including burning, dermatitis or rash, swelling, pigmentary changes, blisters or welts, skin peeling, itching, irritation and tenderness, chemical burns, and increased sunburn.
The FDA also notes studies that confirm the effects of AHAs. For example, one showed that applying AHAs to the skin results in increased sun sensitivity, and after four weeks, volunteers' sensitivity to skin reddening produced by UV rays increased by 18 percent, while their sensitivity to UV-ray-induced cellular damage doubled, on average.
The FDA recommended updated warnings on AHA products to alert users to the increased risk of sunburn. These warnings typically don't mention skin damage or skin cancer risk, however.
Safer, More Nourishing Choices
The Cosmetic Ingredient Review (CIR) expert panel concluded that glycolic and lactic acid are safe for use in cosmetic products at concentrations of 10 percent, “when formulated to avoid increasing sun sensitivity or when directions for use include the daily use of sun protection.”
Sounds like it's safe to use as long as you're extremely careful about sun protection, but still, I question the wisdom of using AHAs long-term. Even the FDA admits that studies “suggest” the sun-sensitivity effects are temporary and go away once you stop using the products, but the agency adds that, “skin sensitivity to UV radiation…may increase after four weeks of topical application of glycolic acid.” They conclude that more studies are needed to determine the lasting effects of AHAs on the skin's ability to withstand UV exposure.
There are gentler, more nourishing alternatives to AHAs. Honey, for example, contains gluconic acid, which is a milder acid that gently exfoliates and brightens the appearance of your skin. Fruit enzymes from papaya (papain) and pineapples (bromelain) also contain low levels of acids that are well tolerated by sensitive skin. Exfoliating sugar scrubs and plant-based scrubs can also help. No matter what type of exfoliating you do, always protect your skin from environmental stressors with natural antioxidants like vitamin E and plant extracts (found in my Anti-Aging Serum, for example), and wear sunscreen with zinc oxide.
Have you had a bad experience with lactic acid or other AHAs? Please share with us.
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Jane E. Allen, “A hidden danger in skin care,” Los Angeles Times, December 16, 2002, http://articles.latimes.com/2002/dec/16/health/he-alpha16.
“Alpha Hydroxy Acids in Cosmetics,” FDA, http://www.fda.gov/cosmetics/productandingredientsafety/selectedcosmeticingredients/ucm107940.htm.
“Guidance: Labeling for Cosmetics Containing Alpha Hydroxy Acids,” FDA, http://www.fda.gov/Cosmetics/GuidanceComplianceRegulatoryInformation/GuidanceDocuments/ucm090816.htm.