AHAs are water-soluble acids that work best on the surface of the skin by improving texture, brightening the complexion, and reducing the appearance of fine lines. Glycolic acid, lactic acid, and citric acid are some of the most popular AHAs on the market, and they are used for slightly different purposes. Glycolic acid is the strongest out of the ones listed, and is best for acne scarring or fine lines. Personally, I find glycolic acid to be a bit too harsh on the face, and better used on the body. Lactic acid and citric acid are gentler than glycolic acid, and are typically best for treating acne scarring and hyperpigmentation. If your skin is rough or dull, or if you’re starting to notice wrinkles or fine lines, an AHA could be a fantastic addiction to your routine. 

BHAs, on the other hand, are oil-soluble, meaning they work both on the surface of your skin and also penetrate deeper into the pores to help with oily and acne-prone skin. BHAs have a larger molecular structure than AHAs and are typically much gentler for use. Salicylic acid is the most commonly used BHA in the skincare industry, and it’s well-known to dissolve excess oil and sebum. If you struggle with blackheads, breakouts, or clogged pores, a BHA is likely the best choice for you. 

So, if you’re not sure what skin problems you have, how do you decide between AHAs and BHAs? In general, if your skin is dry or has been sun-damaged, AHAs are your go-to, while oily and acne-prone skin types will benefit more from BHAs. For combination skin, you can use both, but probably not at the same time! For example, you could stagger their usage by applying an AHA product at night to smooth your complexion and apply a BHA in the morning to prevent breakouts. There are products that combine different AHAs and BHAs, but when using them individually, you should be careful with how you start. 

It’s crucial to start very slowly with exfoliants, by using them a few times a week at a lower concentration. You can gradually increase the frequency of use as your skin builds up a tolerance. Always follow up with a moisturizer to lock in hydration, exfoliants can leave your skin drier than usual. Most importantly, back off for a while if your skin gets dry or irritated (more than can be fixed with moisturizer!), and switch to a gentler acid or lower concentration if it doesn’t get better.

When applying exfoliants, remember: less is more. I learned the hard way by slathering my face with glycolic acid, salicylic acid, and retinol all at once, leaving my skin red and irritated. I made several crucial mistakes— don’t combine multiple exfoliants at the same time, and only use a little! Though it would be nice if putting a little extra product on the night before would give you perfect skin the next morning, you’re more likely to end up worse-off. Over-exfoliation can cause sensitive skin, redness, dryness, and even end up causing more breakouts. 

The most important skincare step is always sunscreen, but it’s even more essential to wear sunscreen when using an exfoliant. When you use any exfoliant, you’re increasing your skin’s sensitivity to the sun, and putting yourself at risk for greater UV damage—-often just reversing any progress you’re making.