Medically reviewed by Vicky Davis, FNP
Written by Our Editorial Team
Last updated 2/2/2022
The world of skin care is full of eye-catching active ingredients that promise fewer wrinkles, less acne and smoother, better-looking skin. While many “miracle” ingredients in skin care offer more hype than substance, others are backed up by real scientific research showing that they work.
Beta hydroxy acids, or BHAs, fit into the second category. These ingredients work by promoting exfoliation, or the peeling of dead skin cells. They’re used to treat acne and many signs of skin aging, such as fine lines, wrinkles and rough skin.
If you’re looking to clear away acne and prevent it from coming back, even out your skin tone or decrease the appearance of fine lines and wrinkles, adding a BHA to your skin care routine may be a smart idea.
Below, we’ve explained what beta hydroxy acids are, as well as how they work as treatments for acne and skin aging. We’ve also dug into the most recent scientific research on BHAs to find out how effective they really are.
Finally, we’ve explained how you can use BHAs and similar skin care products for smoother and less acne-prone skin.
Beta hydroxy acids, or BHAs, are a class of hydroxy acids (HAs) that are frequently used in skin care products. They’re used to treat a variety of skin conditions, including acne in teenagers and adult acne, as well as many common signs of skin aging.
When hydroxy acids first appeared in the world of scientific skin care, they were mostly used in a clinical setting by dermatologists to treat warts and skin conditions like ichthyosis.
BHAs have also been used (and are still in use today) in many cosmetic skin procedures, such as chemical peels for treating acne and preventing skin aging.
Over the last few decades, beta hydroxy acids and related ingredients have had a huge impact on the world of consumer skin care. These days, you can find BHAs as ingredients in cleansers, serums and countless other skin care products available in your local drugstore.
Beta hydroxy acids work by promoting exfoliation, or the removal of dead cells that can build up on the surface layer of your skin.
To understand how BHAs work, it’s important to quickly go over the basics of how skin functions, as well as the natural processes that your skin goes through on a regular basis to maintain itself and keep harmful substances out of your body.
Human skin isn’t just there to look good — it also serves a vital purpose by acting as a protective barrier. This barrier keeps moisture inside your body and provides protection against pathogens, chemicals and allergens that can cause disease and damage to your body.
Every day, your skin is exposed to numerous external sources of damage, from UV radiation to friction, wind and bacteria. In order to repair itself, the epidermis — the outer layer of your skin — regenerates continuously through a process of cell creation called epidermal turnover.
As part of the cell turnover process, new cells are generated by stem cells in the basal layers of your skin. These cells travel towards the surface and replace the old, damaged cells that make up the outermost layer of your skin.
Over time, your body naturally sheds the dead, leftover skin cells from this process. However, in the meantime, the dead skin cells that are replaced via the epidermal turnover process can play a role in several common skin care issues.
First, when dead skin cells build up en masse, they can mix with a substance called sebum — a type of natural oil that’s secreted by your sebaceous glands.
This debris can clog the hair follicles inside your skin (also referred to as pores), leading to acne breakouts. When bacteria multiply inside these clogged pores, it can result in the development of painful inflammatory acne and cystic acne.
Second, when dead skin cells aren’t shed regularly, they can “clump” together, causing your skin to appear scaly, rough and dull.
By promoting the exfoliation of dead skin cells, beta hydroxy acids have several major skin care benefits:
Treating acne breakouts. By peeling away dead skin cells, BHAs can help to get rid of the whiteheads and blackheads that can develop on your skin. This can give your skin a smoother, more consistent appearance.
Stopping acne breakouts from coming back. Since BHAs promote the peeling of skin cells, they can reduce the risk of acne lesions making an unwanted comeback once you get rid of your initial breakouts.
Smoothing rough skin. Some beta hydroxy acids can improve the texture of rough and uneven skin, giving your skin a smoother appearance and feel.
Treating wrinkles and other signs of aging. BHAs can lighten and reduce the visibility of many common signs of skin aging, including lentigines (age spots), facial wrinkles and fine lines.
Some beta hydroxy acids are also used to treat skin conditions. For example, the beta hydroxy acid salicylic acid is commonly used to treat melasma, a skin condition that can involve brown, darkened patches that develop on the skin.
The most common beta hydroxy acid used in skin care is salicylic acid, a natural chemical that’s derived from willow bark. Salicylic acid is commonly used to treat acne and can be found as an active ingredient in cleansers, toners and other products.
Other BHAs include:
These acids are less commonly used in skin care products. You can see if a skin care product contains beta hydroxy acids by checking for ingredients such as salicylic acid on the product’s ingredient list.
Beta hydroxy acids and alpha hydroxy acids are common active ingredients in facial cleansers and other skin care products. They have similar effects, with both types of ingredients acting as exfoliants that remove dead skin cells.
The difference between beta hydroxy acids and alpha hydroxy acids is their solubility. BHAs are oil-soluble ingredients, meaning they can dissolve in lipids. AHAs are water-soluble ingredients, meaning they’re dissolvable in water.
Because beta hydroxy acids are absorbed through oils, they can penetrate the skin through the sebaceous follicles. This makes them particularly useful ingredients for people with comedonal acne such as whiteheads, as well as people with naturally oily skin.
From a chemical perspective, BHAs and AHAs are extremely similar. AHAs feature a hydroxyl group attached at the alpha position of the carboxyl group, whereas BHAs have their hydroxyl group attached at the beta position of the carboxyl group.
Some AHAs, such as malic acid and citric acid, even have chemical features of BHAs, such as carboxyl groups at both positions. These acids are sometimes called “crossover” acids due to their unique chemical structure.
Chemistry lesson aside, both types of acids work well as skin care ingredients. Like BHAs, most AHAs can strip away dead skin cells to improve your skin’s texture, lighten wrinkles and prevent acne from developing.
Put simply, yes. Like most alpha hydroxy acid substances, researchers have studied the effects of beta hydroxy acids on acne, fine lines and other common skin issues, with research showing largely positive results.
Most research involving beta hydroxy acids looks at the effects of salicylic acid, the most widely used beta hydroxy acid in skin care.
In a review published in the Journal of Clinical and Aesthetic Dermatology in 2012, researchers looked at the results of several studies involving salicylic acid treatments for acne.
They found that both over-the-counter skin care products that contained a mild concentration of salicylic acid and clinical peeling solutions that contained 30% salicylic acid helped to get rid of acne lesions.
Other research has found that salicylic acid peeling helps to reduce skin roughness, even dark spots, improve blotchy skin tone and reduce the appearance of fine lines.
It’s worth noting that the precise concentration of salicylic acid in many skin care products may vary, meaning not all products will produce the same results on acne, discoloration and certain signs of skin aging.
Using beta hydroxy acids for better skin is a simple process. You can use beta hydroxy acids at home with over-the-counter hydroxy acid products, or make use of BHA-based peeling services offered by dermatologists and other skin care professionals.
One of the easiest ways to enjoy the benefits of beta hydroxy acids is by adding BHA-containing products to your skin care routine.
You can find BHAs as active ingredients in cleansers, scrubs, masks, toners and other skin care products available online and in drugstores. Most products that contain BHAs can be purchased without a prescription.
Make sure to follow the instructions provided with your skin care products. Avoid using any skin care product more often than recommended, as this may increase your risk of experiencing side effects.
Acne and anti-aging products that contain BHAs may cause skin irritation, dryness and stinging, meaning you may want to use a moisturizer after applying them to your skin.
Some beta hydroxy acids are used in chemical peeling procedures provided by dermatologists and plastic surgeons.
BHAs are often used in combination with AHAs for light chemical peels, which are designed to treat dryness, acne, fine wrinkling and uneven skin tone. This type of peel usually targets the outermost layer of your skin, called the epidermis, for a healthier texture and glow.
You may want to consider a chemical peel using BHAs and/or AHAs if you have more serious acne or visible signs of aging that don’t respond to over-the-counter products.
Chemical peel procedures can range in price, and recovery can take several days. After a light peel with a beta hydroxy acid, you may experience some redness, flaking, stinging and irritation that gradually subsides.
Just like with other over-the-counter skin care products, you’ll get the best acne prevention and anti-aging results by using beta hydroxy acids strategically. Try the following tips to reduce your risk of side effects and enjoy clearer, smoother skin:
Start with a low concentration. If you have sensitive skin, consider starting with a skin care product that has a low concentration of BHAs. Research shows that even very mild 0.5% salicylic acid products are effective at treating acne.
Never use BHAs on damaged skin. Products that contain BHAs should not be applied to skin that’s broken, swollen, red, irritated or infected. If your skin is damaged, wait for it to heal before applying any products that contain BHAs.
Test BHAs before applying them to your face. To avoid stinging or irritation, try testing any products that contain BHAs (or similar ingredients, such as AHAs) on a small area of your skin before applying them to your face.
Use sun protection with BHAs. Some products that contain BHAs may make your skin more sensitive to sunlight. Keep your skin protected by applying a broad-spectrum, SPF 30+ sunscreen and wearing protective clothing.
Wait several weeks before judging your results. Many BHAs are effective at treating acne and the signs of skin aging. However, results aren’t immediate, meaning you may need to wait several weeks before you can see improvements.Your skin may look worse during the first few weeks of treatment before improving. It’s important to be patient and wait for a few weeks before assessing your results from any skin care products, including those that contain BHAs.
Talk to your healthcare provider if you experience side effects. Some BHAs, such as salicylic acid, may cause dryness and irritation, especially during the first few weeks of use. Make sure to talk to your healthcare provider if you experience persistent or severe side effects from products that contain BHAs or AHAs.
While some aspects of the aging process are unavoidable, taking good care of your skin plays a major role in helping you look your best in every decade of your life.
Used effectively, beta hydroxy acids like salicylic acid can help you to prevent acne breakouts, reduce the visibility of wrinkles and give your skin a smooth, consistent texture and tone.
You can learn more about taking care of your skin using proven, science-based ingredients in our guide to developing a face care routine. You can also access our full range of prescription acne treatments and other skin care products online.