What You Need To Know About Skin-Care Acids

They’re not as scary as they sound

Hear the words "acid" and "skin" combined, and it's hard not to be a little scared. You probably can't help but picture a bubbly liquid eating through your skin, leaving nothing in its wake. But get rid of any negative connotations, and instead realize that skin-care acids can actually leave your skin free of clogging and breakouts. Not so scary anymore, right?

Skin-care acids come in many forms, meaning formulas. For the most part, though, they work in three ways: exfoliating, slowing down the aging process, and hydrating. We’re going to go through six acids we think you should know about ahead, but first, let’s back up to why people are so threatened by the idea of putting an acid on their face. We blame that episode of Sex and the City where Samantha gets a chemical peel, and it looks like her face has been dipped in literal fire; Laura Dyer, PA-C, blames it, too. Well, kind of.

“I think, historically, people are scared of what the old-school acids were, the big big acids, the TCAs, the phenol peels that were done way back in the day,” she says. “All of that is definitely a misconception in and of itself because, when used properly, they can leave the skin looking super fresh, glowing, improve fine lines, texture, acne, pigmentation, all those different things with zero downtime and no noticeable side effects.”

Anyone can use skin-care acids, but everyone should proceed with caution when using them for the first time. Always start with the lowest concentration, to see how your skin responds, then feel things out from there. Don’t use it every day, cosmetic chemist Ni’Kita Wilson warns. Start with every three days to get your skin used to a lower pH. She notes that those with darker skin should be particularly careful because you can create unnecessary hyper-pigmentation or dark marks. “But once you get used to it, they are awesome ingredients, they work like no other,” she says.

There are hundreds, if not thousands, types of acids out there, but we’re going to focus on the ones we think are the most important in terms of benefitting the appearance of your skin. We’re discussing them separately, but, Dr. Harold Lancer, celebrity dermatologist, says it’s not uncommon to see multiple acids on the ingredient list for a product. “If you’re the kind of person who cooks, and your favorite ingredient is pepper, well you don't just put pepper into the water and expect to make it a soup,” he explains. Basically, don't be afraid when more than one acid is in a product; they probably work well together and will only aid you on your path to glowy skin. 

Get to know our favorites and what they do, ahead. 

Many acids fall into the AHA, or alpha hydroxy acid, category, but they all essentially do the same thing, which is exfoliate the skin and slough off dead skin cells. The ones you’ve probably heard of the most are glycolic acid, which is made from sugar cane, and lactic acid, which is derived from milk. (Citric, malic, and tartaric acid are some of the others). When used, AHAs help brighten the skin, smooth fine lines, as well as improve the texture and tone.

It’s a do-a-lot ingredient with great benefits. Though cosmetic chemist Randy Schueller warns about using glycolic acid, especially in high concentrations, as it can be pretty intense. “People need to be careful when working with these ingredients because even though they can be purchased on the internet, they can be quite dangerous,” he says. “High concentrations of these ingredients should be administered only by aestheticians or dermatologists.”

BHAs and AHAs are very similar. The main difference being that AHAs are water soluble and preferred for skin that’s normal to dry, while BHAs are oil soluble and preferred for normal to oily skin. Also, when we’re talking BHAs, that doesn’t encompass an umbrella of acids; the only one that falls under the label is salicylic. “It’s good for purging the pores, helps reduce acne, and helps to make the pores appear smaller,” Wilson says. She goes on to explain: “If you're purging and you're breaking apart the junk and gunk in the pores, you're no longer stretching out the walls, so they appear smaller.”

In summary, AHAs help to clear away the surface, while BHAs go a little deeper. Together, they’re a powerhouse, Wilson notes. Dr. Dyer adds that BHAs have natural skin-calming properties, which makes it a great option for those who have sensitive or rosacea-prone skin.

Hyaluronic acid is a tricky one because, though it has the term acid in its name, it doesn’t have any of the exfoliating benefits. In fact, it does the opposite, which is moisturize. As Wilson explains, in science talk, “Hyaluronic acid is too big to penetrate into the skin like the AHA's, so they basically can only sit on the surface, which makes them a great barrier for the skin.” Facts! Hyaluronic acid is often referred to as the be-all and end-all ingredient for hydrating the skin and typically makes its way into products when the temperature starts to dip. It’s a humectant that not only keeps skin plump but also youthful. The more moisture that comes in, the perkier your skin will appear.

Retinol, that semi-intimidating ingredient you hear a lot about but don’t look into, is comprised of retinoic acid. If you’re in your 20s, you’ve likely heard whisperings; if you’re in your 30s, you might even already be using it in your daily routine. It’s essentially what you should be using if concerns about wrinkles are starting to creep up. “It has real anti-aging benefits like stimulating collagen production and things of that nature,” Wilson says. “So it has much stronger anti-aging and skin rejuvenating [benefits] than glycolic acid and AHAs do.” It can be finicky, especially for those with sensitive skin, and is best approached slowly. Once you’re on the retinol train though, there’s no turning back.

We’ve gone into great detail about what ascorbic acid does here, but, in short, it’s another term for vitamin C. “It's not an AHA, but it kind of works hand in hand with retinol. It doesn't really promote cell turnover, but it does help with stimulating collagen, and it does help with melanin,” Wilson explains. Meaning, it’s a godsend for those suffering from hyper-pigmentation or dark spots. Smokers should also take note, ditto those living in big cities. In fact, a lot of people can benefit from this one.

Ferulic acid is probably the tamest acid of the bunch. It’s great as an antioxidant (against free radical exposure, which can cause premature aging), but doesn’t provide you with the benefit of exfoliating or pore purging. It’s found naturally in the seeds of apples, oranges, vegetables, and grains. It's also been picking up in popularity, so expect to see it here, there, and everywhere.