What is the difference between AHA vs BHA skincare exfoliants? AHA stands for alpha hydroxy acid and BHA stands for beta hydroxy acid. Each type of acid has different benefits and targets different skin issues.
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What are AHAs?
Alpha hydroxy acids (AHAs) are water-soluble acids. Derived from botanical sources such as plants and fruits, alpha hydroxy acids exfoliate the skin. Essentially, they break apart the glue that holds skin cells together, sweeping away dead skin cells which can make skin cells dull, clogged, and uneven.
The Types and Benefits of AHAs
Alpha hydroxy acids exfoliate epidermal cells in the stratum corneum layer of the skin. As dead skin cells are sloughed away, a brighter fresher complexion is revealed. AHAs have been used for several years to treat many skin issues including acne, scars, hyperpigmentation, and melasma, thanks to their ability to reduce blemishes and brighten the skin.
AHAs also help improve skin barrier function, increase hydration, and dermal and epidermal thickness. Alpha hydroxy acids support skin’s natural moisturizing factors and stimulate collagen production making them ideal for those concerned with the visible signs of aging like wrinkles, fine lines, age spots, and loss of elasticity and firmness.
NOTE: Alpha hydroxy acids may increase skin’s sensitivity to sunlight, so it is important to apply a broad-spectrum sunscreen of SPF 30 or higher while using AHAs and for 7 days after.
AHA Concentrations and pH
The higher the concentration of AHAs, the lower the pH, and as a result, the chances for irritation and damage to the skin are higher. The trick with using alpha hydroxy acids is finding the optimized concentration for your skin to reap the multiple benefits that they offer.
While there are some AHA formulas on the market for at-home use (and used by skincare professionals in treatments) at much higher concentrations, per the FDA, AHAs glycolic and lactic acid can safely be used at concentrations under 10% with a final pH of 3.5 or higher.
Derived from sugarcane, glycolic acid has the smallest AHA molecule size and can penetrate the skin more deeply than other AHAs. Glycolic acid supports cellular renewal targeting dullness, uneven skin tone, and texture. While highly effective due to its molecule size, it may also be irritating to those with sensitive skin.
Glycolic acid has been used in skincare peels and treatments for many years to improve acne, acne scars, melasma, hyperpigmentation, and photoaging. Glycolic acid has also been shown to increase collagen and hyaluronic acid in the skin.
Related Post: How to Use Glycolic Acid in Your Skincare Routine
Derived from sour milk, lactic acid is an alpha hydroxy acid that exfoliates the skin as well as firms and thickens the skin. Lactic acid, like other exfoliating acids, sweeps away dead skin cells but since it doesn’t penetrate as deeply as glycolic acid, is less likely to cause irritation.
Lactic acid was tested in this study at concentrations of 5% and 12%. Treatment with 12% resulted in smoother skin and a reduction in the look of fine lines and wrinkles after 3 months. Lactic acid can also prevent and reduce acne as demonstrated in this study.
Derived from almonds, mandelic acid has a larger molecule size than other AHAs and penetrates slower, making it an excellent choice for sensitive skin. It provides many of the same benefits as other AHAs as it exfoliates dead skin cells, increases cell turnover, brightens the skin, unclogs pores, and can help to reduce the appearance of hyperpigmentation and dark spots.
Mandelic acid also offers anti-aging benefits. It has been shown to increase elasticity and firmness in the skin. Mandelic acid has been shown to be antimicrobial and can help improve acne and post-acne scarring, inflammation, and redness. It has also been proven to be an antifungal, and may help with folliculitis. Mandelic acid is the only alpha hydroxy acid that has such strong antifungal properties.
Derived from fermented grapes and other fruits, tartaric acid is an alpha hydroxy acid that has antioxidant properties and helps protect skin from damaging free radicals from the sunlight. Tartaric acid is often used to balance the pH of skincare products to make them more stable.
Tartaric acid is not as strong as other alpha hydroxy acids, so you will often find tartaric acid combined with other AHAs to increase the potency and effectiveness of a formula.
Derived from apples and other fruits, malic acid helps to exfoliate the skin and reduce the appearance of discoloration. Malic acid has been shown to have antibacterial qualities.
Malic acid has a larger molecule size than glycolic acid and lactic acid, so malic acid is another acid that is less potent and less likely to cause irritation. It is often combined with other alpha hydroxy acids to improve formula effectiveness.
Derived from citrus fruits, citric acid is often used to balance the pH of skincare formulas. Citric acid has been shown to increase epidermal and dermal glycosaminoglycans and viable epidermal thickness. Glycosaminoglycans are polysaccharides that play an important role in many processes in the body such as the regulation of cell growth, cell adhesion, and wound repair. Super hydrator hyaluronic acid is a type of glycosaminoglycan.
What are BHAs?
BHAs, or beta hydroxy acids, are oil-soluble acids that work deep in the pores to unclog them, clearing out oil and debris that can lead to acne. BHAs penetrate sebaceous follicles, making them ideal for those with oily and acne-prone skin.
Beta hydroxy acids provide similar benefits as alpha hydroxy acids, but BHAs offer anti-inflammatory properties and are less likely to cause irritation when used correctly.
NOTE: Although BHAs won’t make your skin as sensitive to the sun as AHAs, it is still important to apply a broad-spectrum sunscreen of SPF 30 or higher while using BHAs and every day.
The Types and Benefits of BHAs
The main BHA used in skincare is salicylic acid. Salicylic acid, found in white willow bark and wintergreen leaves, loosens the bond between dead skin cells to exfoliate the skin. Since it gets deep into the pores, it targets oil and buildup to reduce acne and prevent future breakouts and blackheads.
Salicylic acid has been shown to provide an anti-inflammatory effect as well. It can help reduce the look of hyperpigmentation, dark spots, age spots, and other discoloration.
While BHAs have been shown to have somewhat of an antibacterial effect, if you want to use a product that will get rid of p. acnes bacteria, a type of bacteria that leads to acne, consider using a BHA in conjunction with a benzoyl peroxide treatment.
Like AHAs, salicylic acid may be irritating to those with sensitive skin. For those with sensitive skin, a 1% concentration of salicylic acid is ideal for exfoliation.
How to Use AHAs and BHAs
AHAs and BHAs are in a wide variety of skincare products from cleansers, toners, and serums, to moisturizers, peels, and facial masks. How an AHA or BHA product should be used is based on the type of product an AHA or BHA is in.
As I mentioned earlier, the secret is using the optimal concentration of AHAs or BHAs for your skin. It is very important to follow the product instructions on how to use the AHA or BHA product, whether it be a wash-off treatment or leave-on product.
AHA vs BHA: Which One Should You Use?
Your specific skincare concerns and your skin type should factor in to whether you should try an alpha hydroxy acid, a beta hydroxy acids or both in a combined product.
As previously noted, alpha-hydroxy acids can help treat a variety of skincare conditions. While very effective, unfortunately, glycolic acid can be irritating to those with sensitive skin. Gentler acids such as lactic and mandelic also exfoliate skin but are generally better tolerated than glycolic acid. Since AHAs help support skin’s Natural Moisturizing Factors, AHAs are ideal for those with normal to dry skin.
Since BHAs are oil-soluble and work deep into skin cells to clear out pores, combination and oily skin types would benefit from a beta hydroxy acid.
The Main Difference Between AHAs and BHAs
While both chemical exfoliants, the main difference between AHAs and BHAs is that AHAs are water-soluble and BHAs are oil-soluble. While AHAs exfoliate the surface of the skin to improve fine lines, wrinkles, discoloration, skin tone and texture, BHAs travel deeper into pores to clear our dirt, excess sebum and debris.
Using AHAs and BHAs Together
If your skin deals with a little bit of everything, using a product that combines both AHAs and BHAs at the optimal concentration may be your best bet. You can address anti-aging concerns such as fine lines, wrinkles, and dullness, while also reaching deeper into your skin with a BHA to clear out clogged pores.
The Best AHA and BHA Skincare Products
The Ordinary Glycolic Acid Toning Solution 7% is my pick for an affordable glycolic acid product. You get the benefits of 7% glycolic acid formulated at a pH of 3.6 for improved texture, clarity, and radiance.
This toner contains a Tasmanian Pepperberry derivative that helps to reduce potential irritation that comes along with using glycolic acid. This exfoliating toner also contains ginseng root and aloe vera for additional soothing.
The Ordinary notes that glycolic acid has a pKa of 3.6, which indicates acid availability. The closer the pKa to the pH, the better the balance between salt and acidity. The better in balance, the formula is more effective and less irritating.
Paula’s Choice 8% AHA Gel Exfoliant is formulated with 8% glycolic acid to remove dead skin cells and improve skin tone while firming and smoothing the skin. This lightweight gel helps to reduce the look of wrinkles and fine lines and reveals a more radiant complexion.
This exfoliating gel also contains plant extracts including soothing chamomile, hydrating aloe barbadensis leaf juice, antioxidant camellia oleifera leaf extract (green tea), plus sodium hyaluronate and panthenol for hydration.
Instructions are to apply this glycolic acid product once or twice daily after cleansing and toning but I would use this only once a day or once every other day. It really depends on how sensitive your skin is. It is formulated at the optimal pH range of 3.5–3.9.
Related Post: A Guide to Acids in Skincare
Sunday Riley Good Genes All-in-One Lactic Acid Treatment is a highly effective lactic acid serum that exfoliates dull skin for brighter younger-looking skin. In addition to purified lactic acid, this exfoliating serum contains licorice for brightening and radiance, lemongrass for its astringent properties, plus arnica and prickly pear extract to soothe the skin.
It’s been clinically proven to plump fine lines and improve skin radiance in just 3 minutes. Even though it is pricier than some other exfoliating treatments, this serum gives me the most noticeable and immediate difference in the texture of my skin. My skin is always clearer after I use it too.
Paula’s Choice 2% BHA Liquid Exfoliant is Paula’s Choice #1 product worldwide. This customer favorite is a leave-on exfoliant formulated with salicylic acid to unclog pores, even out skin tone, reduce the look of wrinkles and fine lines and brighten your complexion.
Formulated at the optimal pH range of 3.2–3.8 this beta hydroxy acid product exfoliates dull skin. It travels deep into pores to clear out dead skin cells and congestion to reveal brighten and more youthful looking skin.
Related Post: The Best Paula’s Choice Skincare Products
Dr Dennis Gross Alpha Beta Peel combines 5 AHAs/BHA (glycolic acid, salicylic acid, lactic acid, citric acid, and malic acid) at the optimal concentration to sweep away dead skin cells to improve skin tone and smoothness.
Step 1 contains the acid blend along with chamomile for its anti-inflammatory benefits. Step 2 contains retinol for additional smoothing and to improve skin elasticity. Green tea extract offers antioxidant properties.
This is an excellent all-in-one chemical peel. It brightens the skin, refines skin tone, improves clarity, and smoothes out wrinkles and fine lines. It is very easy to use and packaged in single-use packets making it perfect for travel.
AFFORDABLE AHA/BHA COMBINATION PRODUCT: A best-seller from The Ordinary, AHA 30% + BHA 2% Peeling Solution combines 30% AHAs and 2% BHAs in a rinse-off peel. This product contains very high concentrations of direct acids. It should not be used by those with sensitive, peeling, or compromised skin. It should only be used by experienced users of acid exfoliation.
If you are looking for an exfoliating acid that isn’t as strong as glycolic acid or lactic acid, consider a product containing mandelic acid. The Ordinary Mandelic Acid 10% + HA contains 10% mandelic acid. Its molecular weight is 152.1 daltons, which is larger than other alpha hydroxy acids, such as glycolic acid, whose weight is 76.0 daltons. This larger molecule size makes it better suited for sensitive skin.
This mandelic acid serum helps improve uneven tone, textural irregularities, and fine lines. It also contains sodium hyaluronate crosspolymer for hydrating and plumping at multiple levels of your skin.
Final Thoughts on AHA vs BHA Skincare Exfoliants
Whether you choose an AHA or BHA for your skincare concerns, both types of acids will exfoliate your skin and improve texture and tone. If you can’t choose between the two, try an all-in-one AHA and BHA product that will address several issues at once.
When it comes to AHA vs BHA, regardless of which product you choose, but be sure to moisturize your skin after acid use, and don’t forget the sunscreen!
Thanks for reading, and until next time…