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Facial Acids: Know What You Need in Your Skin Care Routine

Choose the right acids for your skin care needs — without overdoing it

Person applying acidic skin care products to skin after bathing.

If you’re living with acne, redness and signs of aging, like wrinkles or sun spots, it’s only natural to want to find a solution that works for you.


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TV commercials, social media and advice from well-meaning friends can make it seem like skin care requires some highly specialized mix of very particular face acids that only the most committed among us are able to use properly.

But in reality, skin care doesn’t have to be complicated. When you understand what all those skin care acids do, it gets easier to pick and choose the ones that work for your needs.

“I always say that simplicity is best, and consistency is key,” says physician assistant Samantha Stein, PA-C. “You have a life, a job, maybe kids to take care of. Taking care of your skin shouldn’t be a burden on your life or your bank account. Your skin care routine has to work for you if you’re going to keep it up.”

And keeping it up is essential because face acids take some time to do their job. And to keep your skin looking its best, they need to be used on the regular.

Stein helps us understand what some of the most common face acids do and how they work, so you can take the best care of your skin.

What do acids do for your skin?

Face acids are exfoliants. They work to turn over layers of dead skin cells quicker than would happen on their own. That means facial acids can help make your skin smoother and brighter. They help fight acne. And they prevent and reverse the damage that leads to issues like redness, age spots and wrinkles.

There are two main kinds of acids used in skin care:

  1. Alpha hydroxy acids (AHAs) are water-soluble acids. They loosen the fluid that binds surface skin cells together. That allows dead skin cells to slough off. “As we age, the glue that holds our skin cells together becomes denser, which slows down the natural cell turnover process,” Stein explains. “AHAs help to loosen up that glue and remove the dead cells that gunk up the top layer of our skin.”
  2. Beta hydroxy acids (BHAs) are oil-soluble acids. They penetrate deeper into your pores than AHAs. Like AHAs, BHAs help remove dead skin. But they also help dissolve sebum, an oily substance your body creates. Excess sebum can lead to acne.

But not all skin care acids fall into these categories. More on that in a bit.


The important thing to remember about all face acids is that their job is to exfoliate, and you don’t want to go overboard.

“To an extent, exfoliating can be a good thing. But too much can also be irritating because you’re essentially stripping the top layer of your skin,” Stein states. “Face acids can be great to help improve your skin’s texture, even out discoloration and other benefits, but you don’t want it to strip it so much that you remove the good parts of the skin, like the structures that hold in water and healthy fats.”

Another thing to remember: Using facial acids can leave you more prone to sun damage. That’s because acids expose healthy, new cells that are more susceptible to the sun. So, Stein says it’s vital to use SPF 30 (or higher) sunscreen on your face every day. Sunscreen will help protect you from sunburn, skin cancer and the aging effects of the sun’s rays.

Quick reference: What do different face acids do?

There are dozens of ingredients in your skin care products that have special jobs to do.

Skin care is a big business. Some reports say the U.S. skin care industry brought in more than $140 billion in 2022. So, there’s a lot of incentive for companies to find and market the next “big thing” in keeping skin young and healthy.

Stein shares more about some of the more common face acids and how they work.

Salicylic acid
Top use(s)
Unclog pores
Type of acid
Hyaluronic acid 
Top use(s)
Anti-aging and dryness
Type of acid
Not a hydroxy acid
Glycolic acid 
Top use(s)
Type of acid
AHA (deep penetrating)
Ascorbic acid 
Top use(s)
Type of acid
Lactic acid 
Top use(s)
Smooth out rough texture; especially good for sensitive skin
Type of acid
Kojic acid 
Top use(s)
Reduce hyperpigmentation
Type of acid
Azelaic acid 
Top use(s)
Reduce redness; especially good for sensitive skin
Type of acid
Not a hydroxy acid

Salicylic acid

Salicylic acid is the most common BHA found in skin care products.

“BHAs like salicylic acid get really deep into the pores, whereas the water-soluble ones don’t go as deep,” Stein says. “That means salicylic acid can help unclog pores by getting in deep and removing sebum and other oils that can lead to breakouts.”

That deep-penetrating action makes salicylic acid a good choice for people who experience blackheads and whiteheads. You’ll find salicylic acid in a lot of products that are marketed as acne treatments, like face washes, toners, serums, pimple patches, moisturizers and more.

Stein adds that though BHAs get deep into pores, salicylic acid isn’t overly irritating to most people’s skin and can be used twice a day for most.


Hyaluronic acid

Rather than an AHA or BHA, hyaluronic acid is a sugar molecule. Your body naturally produces hyaluronic acid. It’s a goopy, slippery substance that helps lubricate and hydrate your whole body, including your skin, joints and eyes.

“Hyaluronic acid helps bind water to collagen, which traps water in the skin. That helps make the skin more plump and full-looking,” Stein explains.

As we age, our bodies naturally produce less hyaluronic acid. That can make your skin drier and less elastic over the years, leading to the development of wrinkles, fine lines and more.

Hyaluronic acid isn’t irritating to most people’s skin and will be most beneficial to people with dry or aging skin. You’ll see it as an ingredient in a whole range of facial products, including cleansers, moisturizers and more.

Glycolic acid

Glycolic acid is an AHA staple in a lot of anti-aging skin care products. That’s because it’s a strong exfoliant that works to smooth out your skin’s surface and refine pores. It also helps with discoloration, fine lines and wrinkles.

One of glycolic acid’s biggest benefits, Stein says, is that with long-term use, it can boost collagen production. As you age, your body naturally produces less collagen. That’s the protein that provides structure, support and strength to your skin. Less collagen can lead to crepey, saggy and wrinkled skin.

You’ll want to take it easy when you start using glycolic acid, though, because it penetrates deeper than some other acids. That’s because glycolic acid molecules are very small. So, they can easily wiggle their way deep into your skin and set up shop.

“Glycolic acid can be very strong and irritating,” Stein says. “You’ll want to start slowly.” Start by using glycolic acid just once or twice a week at night. Over time, you can use it more frequently, if it’s not irritating to your skin.

Ascorbic acid

Ascorbic acid is another name for vitamin C, which is a very popular and helpful ingredient in a number of skin care products.

Ascorbic acid is an antioxidant. It works to fight off free radicals in our bodies and our environment. Free radicals are unstable molecules that come from pollutants and sun exposure, among other causes. Antioxidants like ascorbic acid keep free radicals from building up. That’s important because a buildup of free radicals causes oxidative stress. For your skin, oxidative stress can cause wrinkles, sun spots and other signs of aging.


In addition to fighting off free radicals, ascorbic acid, like glycolic acid, helps increase collagen production.

Stein recommends using vitamin C each morning. Using it as a serum will give you the most concentrated dosage, but many moisturizers and other products may include ascorbic acid as well.

Lactic acid

Lactic acid is one of the gentler AHAs, making it a good choice for sensitive skin. Lactic acid acts as both an exfoliant and a moisturizer.

One of its most common uses is to control the skin condition keratosis pilaris, which are painless bumps caused by a buildup of dead skin around your hair follicles. Some people get these bumps on their face, particularly their cheeks. It’s also common on the upper arms, legs, back and more. So, you’ll often find lactic acid in body washes in addition to products meant for your face.

Kojic acid

Kojic acid an AHA most commonly used for people experiencing dark spots or patches, called hyperpigmentation.

People experience hyperpigmentation for a variety of reasons, including sun damage, acne and the skin condition melasma, which is often called the “mask of pregnancy” but can happen in anyone.

“Koji acid works by inhibiting the formation of tyrosine,” Stein explains. “Tyrosine is an amino acid that is needed to produce melanin, which is the substance that gives color to our eyes, hair and skin.”

Because of how kojic acid works on melanin, it can have a lightening effect, but only on areas of the skin that are experiencing a surge of melanin, Stein notes. It won’t change your original skin tone.

Kojic acid is usually well tolerated, but it can cause an allergic reaction in some people.

Azelaic acid

Azelaic acid is neither an AHA nor a BHA. Instead, it’s a dicarboxylic acid, which essentially does the work of both an AHA and BHA — working at the surface of your skin and also penetrating deeply.


“Azelaic acid is most effective in evening out your skin tone and can help clear up redness, rosacea and melasma,” Stein says. “It’s a good choice for sensitive skin because it’s a larger molecule. It’s also a good choice for people who are pregnant.”

How to start using facial acids

If you’re using a serum facial acid, your best choice is to use it in the evening. Apply it after cleansing your face with a gentle face wash and before putting on moisturizer. (And don’t forget the sunscreen in the morning!)

If you’re new to using facial acids, Stein reiterates that it’s important to take it slow. Some of these products can be irritating to the skin or cause allergic reactions. So, you’ll want to use just one product for a bit and see how you react before adding another. Otherwise, you won’t know what works for you and what doesn’t.

And as you add new products to your skin care routine, expect that you may likely experience a time of “skin purging.” That’s normal and healthy and can last a few weeks.

Skin purging is a sign that your skin is experiencing rapid turnover. It may look as if you’re breaking out in acne, but in reality, it’s a sign that your products are doing their job and getting rid of impurities.

“Purging is often misinterpreted as a breakout or a sign of an allergic reaction,” Stein says. “But as long as the products aren’t heavily irritating your skin or causing a lot of stinging, itching or redness, you want to stick with them. Purging is totally normal, and it’s temporary.”

With so many products on the market that claim to do this-that-and-everything to get that smooth, glowing skin you’re looking for, it’s easy to be overwhelmed. And it’s easy to want to buy up every product you see and slather it all over your face in hopes of looking like those “after” photos.

Stein says skin care doesn’t need to be so complex. And it doesn’t need to cost a fortune.

“If you have questions about your skin care routine or what acids or other ingredients you should use, talk to a dermatology specialist,” she encourages. “We’re here to help you find the right products for your skin’s needs and can help take the guesswork out of the process.”

Learn more about our editorial process.

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