Alpha-hydroxy acids (AHAs) are a group of plant and animal-derived acids used in a variety of skincare products. These include daily anti-aging products, such as serums, toners, and creams, as well as occasional concentrated treatments via chemical peels.
There are seven types of AHAs commonly used in products available throughout the skincare industry. These include:
- citric acid (from citrus fruits)
- glycolic acid (from sugar cane)
- hydroxycaproic acid (from royal jelly)
- hydroxycaprylic acid (from animals)
- lactic acid (from lactose or other carbohydrates)
- malic acid (from fruits)
- tartaric acid (from grapes)
Research on the uses and efficacy of AHAs is extensive. However, out of all the AHAs available, glycolic and lactic acids are the most promising and well researched. These two AHAs are also to cause irritation. Because of this, most over-the-counter (OTC) AHAs contain either glycolic or lactic acid.
AHAs are primarily used to exfoliate. They can also help:
- promote collagen and blood flow
- correct discoloration from scars and age spots
- improve appearance of surface lines and wrinkles
- prevent acne breakouts
- brighten your complexion
- increase product absorption
AHAs are primarily used to exfoliate your skin. In fact, this is the foundation for all of the other benefits AHAs offer.
Exfoliation refers to a process where the skin cells on the surface shed off. This helps remove dead skin cells but also makes way for new skin cell generation.
As you age, your natural skin cell cycle slows down, which can make dead skin cells build up. When you have too many dead skin cells, they can accumulate and make your complexion look dull.
Dead skin cell accumulation can also enhance other underlying skin issues, such as:
- age spots
Still, not all AHAs have the same exfoliating power. The amount of exfoliation is determined by the type of AHA you use. As a rule of thumb, the more AHAs contained in a product, the more powerful the exfoliating effects.
For more intense exfoliation, try the Performance Peel AP25 by Exuviance. This peel contains glycolic acid and may be used up to two times per week for best results. You can also consider a daily AHA exfoliant, such as the this daily moisturizer by Nonie of Beverly Hills.
When these acids exfoliate your skin, dead skin cells are broken down. The new skin revealed beneath is brighter and more radiant. AHAs with glycolic acid can help break down skin cell accumulation, while products with citric acid can brighten your skin even further.
For daily benefits, try out Mario Badescu’s AHA and Ceramide Moisturizer. It contains citric acid and aloe vera gel for both brightness and soothing effects. Juice Beauty’s Green Apple Peel Full Strength can be used up to twice a week to deliver brighter skin via three different AHAs.
Collagen is a protein-rich fiber that helps keep your skin plump and smooth. As you age, these fibers break down. Sun damage may also accelerate collagen destruction. This can result in sallow, sagging skin.
Collagen itself is in the middle layer of your skin (dermis). When the upper layer (epidermis) is removed, products such as AHAs can go to work on the dermis. AHAs may help promote collagen production by destroying old collagen fibers to make way for new ones.
For a collagen boost, try out Andalou Naturals’ Pumpkin Honey Glycolic Mask.
AHAs are known for their anti-aging effects, and surface lines are no exception. One reported that 9 out of 10 volunteers who used AHAs over a three-week period experienced significant improvements in overall skin texture.
Still, it’s important to remember that AHAs work for surface lines and wrinkles only, not deeper wrinkles. Professional fillers from a doctor, as well as other procedures such as laser resurfacing, are the only methods that work for deep wrinkles.
AHAs have anti-inflammatory properties that can help promote blood flow to the skin. This can help correct pale, dull complexions. Proper blood flow also ensures that skin cells get the necessary nutrients needed via oxygen-rich red blood cells.
To improve dull skin and related lack of oxygen, try out this daily serum from First Aid Beauty.
Your risk for skin discoloration increases with age. For example, flat brown spots, known as age spots (lentigines), may develop as a result of sun exposure. They tend to develop on areas of the body that are exposed to the sun most often, such as your chest, hands, and face.
Discoloration may also result from:
- post-inflammatory hyperpigmentation
- acne scars
AHAs promote skin cell turnover. New skin cells are evenly pigmented. In theory, long-term use of AHAs may reduce skin discoloration by encouraging the old, discolored skin cells to turn over.
The American Academy of Dermatology recommends glycolic acid for discoloration.
You may be familiar with benzoyl peroxide and other acne-fighting ingredients for stubborn blemishes. AHAs may also help treat and prevent recurring acne.
Acne pimples occur when your pores are clogged with a combination of dead skin cells, oil (sebum), and bacteria. Exfoliating with AHAs can help loosen and remove the clog. Continued use may also prevent future clogs from forming.
AHAs may also reduce the size of enlarged pores, which are commonly seen in acne-prone skin. Skin cell turnover from exfoliating glycolic and lactic acids can even reduce acne scars. Some acne products also contain other AHAs, such as citric and malic acids, to help soothe inflamed skin.
And AHAs aren’t just for your face! You can use AHA products on other acne-prone areas, including your backside and chest.
According to the Mayo Clinic, it can take two to three months before you start to see significant acne improvements. It’s important to be patient while the products work to relieve acne over time. You also need to use the products consistently—skipping daily treatments makes it take longer for the ingredients to work.
Try an acne-clearing gel to get rid of dead skin cells and excess oil, such as this one from Peter Thomas Roth. Acne-prone skin can still benefit from an AHA peel, but make sure you look for one designed for your skin type. Try out Juice Beauty’s Green Apple Blemish Clearing Peel for acne-prone skin.
In addition to their own distinct benefits, AHAs can make your existing products work better by increasing their absorption into the skin.
For example, if you have too many dead skin cells, your daily moisturizer just sits on top without hydrating your new skin cells underneath. AHAs like glycolic acid can break through this layer of dead skin cells, enabling your moisturizer to hydrate your new skin cells more effectively.
To increase daily product absorption with AHAs, try out a toner you use after cleansing and prior to your serum and moisturizer, such as Exuviance’s Moisture Balance Toner.
As a rule of thumb, the FDA recommends AHA products with an overall AHA concentration of less than 10 percent. This helps prevent side effects from AHAs.
According to the Cleveland Clinic, you shouldn’t use products that are more than 15 percent AHA.
Daily use products — such as serum, toners, and moisturizers — contain lower AHA concentrations. For example, a serum or a toner might have a 5 percent AHA concentration.
Highly concentrated products, such as glycolic acid peels, are used less frequently to reduce your risk of side effects.
If you’ve never used AHAs before, you may experience minor side effects while your skin adjusts to the product.
Temporary side effects may include:
- dermatitis (eczema)
To reduce your risk of irritation, the Cleveland Clinic recommends using AHA products every other day. As your skin gets used to them, you can then start applying AHAs every day.
Also use extra caution when going out in the sun. The peeling effects of highly-concentrated AHAs may make your skin more sensitive to UV rays for up to one week after use. You should wear sunscreen daily and reapply more frequently to prevent sunburn.
You should consult your doctor before use if you have:
Women who are pregnant or breastfeeding should also consult their doctor before use. If your doctor says it’s okay for you to use AHA products, consider something targeted to pregnancy, like Juice Beauty’s Green Apple Pregnancy Peel.
- There are multiple AHAs, whereas salicylic acid is the only BHA.
- AHAs may be more appropriate for age-related skin concerns, such as fine lines and wrinkles.
- BHAs might be best if you have sensitive, acne-prone skin.
- If you have more than one skin concern, you can experiment with both AHAs and BHAs. Be sure to incorporate products gradually to reduce irritation.
Another commonly used acid on the skincare market is called beta-hydroxy acid (BHA). Unlike AHAs, BHAs are primarily derived from one source: salicylic acid. You may recognize salicylic acid as an acne-fighting ingredient, but this isn’t all it does.
Like AHAs, salicylic acid helps to exfoliate the skin by removing dead skin cells. This can help clear blackheads and whiteheads by unclogging pores made from trapped dead skin cells and oil in the hair follicles.
If you have more than one skin concern, you might experiment with both AHAs and BHAs, but you should approach with caution. AHAs may be more appropriate for age-related skin concerns, while BHAs might be best if you have sensitive, acne-prone skin. For the latter, you might consider using BHAs every day, such as a salicylic acid toner, and then use a weekly AHA-containing skin peel for deeper exfoliation.
When using multiple products for your skin, it’s important to incorporate them into your regimen gradually. Using too many AHAs, BHAs, and chemicals at once can cause irritation. In turn, this can make wrinkles, acne, and other skin concerns more noticeable.
If you’re looking for significant exfoliation, then AHAs may be the right products for you to consider. You can opt for daily exfoliation with AHA-containing serums, toners, and creams, or do a more intense peel treatment once or twice a week.
AHAs are among the most-researched beauty products because of their strong effects, but they aren’t for everyone. If you have preexisting skin conditions, talk to your dermatologist or skin care specialist first before trying these types of products. They can help you determine the best AHA for your skin type and skin care goals.
Over-the-counter AHAs don’t have to undergo scientific proof of their efficacy before being placed on the market, so only purchase products from manufacturers you trust. You may also consider getting a professional-strength peel at your doctor’s office.