Everything You Need To Know About Using AHAs And BHAs To Get Glowing Skin

Lactic? Glycolic? The basics of exfoliating acids.


When used properly, a mild skincare acid—either in the form of alpha-hydroxy acids (AHAs) or beta-hydroxy acids (BHAs)—can work wonders on your skin. The main benefit of AHAs and BHAs is that they exfoliate, breaking down dead skin cells for a clearer, more glowing complexion. But, while acids can give you that covetable glow, using them incorrectly can cause irritation and redness. Read on to learn the ins and outs of exfoliating skincare acids from two experts: Brenda Patten, a nurse practitioner at The Beauty Clinic by Shoppers and Dr. Zaki Taher, a dermatologist and associate professor with the Faculty of Medicine at the University of Alberta.

What are skincare acids—and what are the benefits of using them?

When you use a skincare product with an acid it promotes skin turnover to reveal smoother, less-congested skin. There are a few different types of acids available—some target acne, some target dark spots and some work more deeply to target wrinkles and fine lines, says Taher. AHAs and BHAs get rid of dead skin cells that can cause dullness and breakouts and they help promote cell turnover. Dead skin cells also block the surface of your skin from absorbing other skincare products you apply on top—and can potentially clog pores. Using an acid regularly whisks them away for a more-glowing complexion. They can also improve pore size, hydration and overall skin texture, says Patten.

What are the different types of acids?

While there are multiple types of skincare acids, there are only a few key ones that are commonly used for exfoliation. The two most famous alpha-hydroxy acids are glycolic and lactic acid, explains Taher. (Glycolic and lactic are very similar, but lactic tends to be a bit gentler on the skin, making it a great option for first-timers or sensitive skin types.) Salicylic acid is the most well-known beta-hydroxy acid.

How should I use AHAs like glycolic and lactic acid and BHAs like salicylic acid?

“Glycolic and lactic acid break up the dead skin cells on the surface of the skin and help to smooth, exfoliate and remove superficial pigment on the outer layer of skin and can even help with some aspects of acne,” says Taher. “Salicylic acid is extremely useful for acne prone skin, oily skin with a tendency to become congested and mild acne.” Salicylic acid penetrates deeper in the skin than AHAs to remove build-up, help banish blemishes and unclog pores. Essentially, AHAs exfoliate the surface of the skin to target roughness and uneven texture while BHAs exfoliate deeper in the pores to fight excess oil and build-up.

What is the best way to incorporate an exfoliating acid into my skincare routine?

“Acids should be integrated into your skincare routine slowly in the form of a cleanser, toner or a serum depending on your concerns,” advises Patten. If you’re looking to try a concentrated serum or toner that contains active acid ingredients, both Patten and Taher recommend introducing it gradually and using the product only once or twice a week until your skin builds up a tolerance. As your skin builds up this tolerance an acid may be integrated more often, says Patten. For AHAs like glycolic and lactic, start off slow and low by using a lower percentage acid (think around 5 percent) a few times a week to see how your skin handles it. For newbies, a safe bet is using a pre-soaked toner pad on freshly cleansed skin as each one holds just the right amount of product, so there’s no chance of overdoing your application. Follow up with your serum, moisturizer and sunscreen. If all goes well, you can slowly up your per-week application and eventually up the percentage (the maximum allowed in Canada is 30 percent in over-the-counter formulas). Taher says that impactful results should appear between two to four weeks after consistent use, when you’ll notice clearer, more radiant skin.

For salicylic acid, concentration typically ranges from 0.5 to 2 percent in products—make a selection depending on what your skin can handle. Patten adds that the slow and low method is particularly important for sensitive skin types, while those with oilier skin can generally tolerate acids a bit easier. Still not sure? Ask an expert. “Everyone’s skin reacts and responds differently so it is best to choose an exfoliating regime with the help of an experienced skincare specialist,” says Patten.

When should I use a skincare acid?

Both AHAs and BHAs can be used day or night on the skin. Some formulas are created to be used at night as an overnight peel, while others (often serums) are meant to be used daily in your morning routine to gently slough off any dead cells on your skin. No matter what time of day you use your skincare acid, always wear proper sun protection during the day—acids can make your skin more sensitive to the sun.

When it comes to product selection, does more expensive equal better?

According to Patten and Taher, prices can vary widely when choosing an over-the-counter product—and you generally get what you pay for. But it isn’t always easy to judge the quality of a skincare product on price alone. Some more-expensive formulas might contain fragrances or additional ingredients that could irritate the skin, while some less-expensive items might have too-harsh formulas that will do the same. Both experts agree that since there is no hard and fast rule, it’s best to begin with a mild product that is within your price range and slowly test it on your skin before proceeding to an additional product or increased concentration.

If you have a specific skincare concern you want to target (like dullness or breakouts), Patten suggests chatting with someone at a skincare clinic or a dermatologist. “Medical-grade skincare products are designed to address specific concerns, so this may be an interest to you if you feel your over the counter acid isn’t delivering the results you had hoped for.”

What should I do if my skin has a bad reaction to an acid?

“There are a variety of reasons for having a reaction to an acid or any skincare product, including allergy, excessive application or using active ingredients in the wrong combination,” says Patten. If you experience an adverse reaction to an acid, like irritation or redness, Patten and Taher suggest stopping your treatment and seeking advice from a skincare specialist if it doesn’t improve. But just because you have one bad reaction doesn’t mean you have to swear off acids altogether—try a lower dosage or a different form of acid. “Giving the skin some time to recover is important, but there is no need to be afraid or to shy away from trying something else in the future,” says Taher. It should be noted as well that all forms of skincare acids should not be used near your eyes, for obvious reasons—plus the skin under your eyes is thinner and tends to be more sensitive.

Can I pair acids with other skincare ingredients?

If you’re thinking of layering skincare acids, some skin types might not have an issue but others may experience redness or irritation. Unless you’re experienced with exfoliating acid-based skincare, Patten advises introducing one new product at a time and if your skin becomes irritated then it may need to be introduced at a lower frequency or it may not be the right product for you. If you’re using other active ingredients, like retinol, tread carefully. “Adding an acid may cause irritation and redness and should not initially be applied together until you skin builds up a tolerance,” says Patten. Once your skin has adjusted to using an acid, you’re able to use exfoliating acids with retinol and other active ingredients, just not at the same time. Instead, try an acid in the morning and a retinol at night or an acid one night and a retinol the next night.