The world of skin care can be a beautiful one when it involves the right products and a glowing complexion. It can also be super confusing, with trendy new ingredients popping up at every corner and clean beauty vernacular dominating the market. A large part of skin care that can be both rewarding and intimidating, all at the same time? Acids. Acids in skin care can make what should be a fun jaunt through the beauty aisle feel like a morning in chemistry class, and though the name may be off-putting, acids remain a hero ingredient in many skin care formulations — and for good reason. Keep scrolling to learn everything there is to know about the 12 most popular skin care acids (both old and new), how they can benefit your complexion, and best practices to ensure you’re using them safely.
Skin Care Acids: Glycolic Acid
Glycolic acid is an alpha hydroxy acid (AHA) that’s derived from sugar cane. It’s a popular choice in anti-aging skin care products because it helps promote cell turnover (aka the shedding of dead skin to reveal new skin) and collagen production. It also offers mild exfoliation on the surface of the skin. “Glycolic acid is the smallest acid in size, meaning the molecule can penetrate deep into the skin,” says board-certified dermatologist Dr. Dendy Engelman of Shafer Clinic. “This makes it very effective at breaking down skin cells and removing dead particles.” Glycolic acid also boosts collagen and elastin production, making it a great ingredient for anti-aging products.
As with any AHA, glycolic acid can increase your chances of sunburn, so be sure to lather on SPF 30 after using a glycolic acid skin care product. (PS: If you have severely sensitive skin, go for lactic acid — it’s a milder AHA that’s better tolerated among this skin type.) Keep scrolling to learn more.
Skin Care Acids: Lactic Acid
Lactic acid, an AHA, is derived from milk and best known for its pigment-perfecting properties (think: discoloration and age spots). It also has collagen-building effects, says Dr. Luigi L. Polla, Geneva-based dermatologist and founder of Forever Institute and Alchimie Forever. “Like all acids, lactic acid exfoliates by removing the upper layer of the stratum corneum to reveal brighter skin and enable better penetration of all topical products,” explains Dr. Polla. “Lactic acid is typically considered a gentle acid and rarely generates any side effects, but the usual precautions of post-acid use are of course recommended (namely no exposure to sun and no waxing for 24 hours post-use).” Keep this acid in your back pocket if you have sensitive skin.
Skin Care Acids: Hyaluronic Acid
You may have heard that dry skin and hyaluronic acid go together like bread and butter, and that’s because hyaluronic acid attracts water (making it a humectant) and thus, helps with hydration. “Hyaluronic acid, a sugar that’s found in our body naturally, maintains lubrication, and boosts collagen production,” says aesthetic and surgical dermatologist Dr. Naissan Wesley. You’ll likely see this collagen support response when HA is used as an injectable filler, but if you’re not quite ready to go that route (yet you still want plump skin), look for topical hyaluronic acid in serums, masks, and moisturizers.
Skin Care Acids: Retinoic Acid
Think of retinoic acid as the fairy godmother of all acids. It’s an extremely effective acid that has the ability to connect to almost any skin cell receptor site and tell it to behave like a healthy, younger skin cell, Dr. Engelman tells TZR. “It also functions as an antioxidant that can combat the free radical damage process that causes wrinkling and other signs of aging.” Continued use of retinoic acid can help improve fine lines and wrinkles, tone and texture, and skin barrier strength. It’s also the strongest retinoid available, and is what other topical retinoids (like retinal & retinol) have to convert to in order to work on your skin.
You can ask your doctor or dermatologist about adding prescription retinoic acid to your skin care regimen to ward off early signs of aging or help with treating acne. Dr. Engelman notes that pregnant women should not use retinoic acid, and those with sensitive skin should use it cautiously.
Skin Care Acids: Salicylic Acid
Salicylic acid is a BHA best known for combatting and fending off acne thanks to its antibacterial, anti-comedogenic properties. Dr. Wesley says that because salicylic acid penetrates oil glands, it helps to reduce the inflammation and oiliness that’s often associated with acne. You can find salicylic acid in everything from cleansers to moisturizers to acne spot treatments. Incorporate it into your routine to clear acne-causing bacteria if you’re dealing with breakouts or if your clogged pores are in need of a deep clean.
Skin Care Acids: Ferulic Acid
Ferulic acid is an AHA found in the cell walls of plants. Dr. Wesley says it has antioxidant benefits to help [neutralize] free radicals in the skin that are created by sun and environmental damage. Most skin types can tolerate ferulic acid, but it’s best for photodamaged or aging skin, especially when used in combination with other antioxidants such as topical vitamin C. Store your ferulic acid skin care products in a cool area (not your steamy wet room) to prevent oxidization.
Skin Care Acids: Tranexamic Acid
Have melasma? Tranexamic acid will be your new go-to. Though relatively new to the playing field, Dr. Polla says tranexamic acid can be used to even out pigment, reduce melanin synthesis, and brighten the skin (especially when paired with vitamin C). Tranexamic acid is more likely to pop up on a serum’s ingredient list, but you can find it in moisturizers and masks too. To keep your skin from drying out, avoid using tranexamic acid with other acids.
Skin Care Acids: Hypochlorous Acid
Hypochlorous acid has a laundry list of skin care benefits and is somewhat of a unicorn when it comes to acids in skin care. Besides the fact that it has broad-spectrum antimicrobial activity and is highly active against bacterial, viral, and fungal microorganisms, Dr. Polla notes that it’s also helpful in managing inflammatory skin disorders such as seborrheic dermatitis, atopic dermatitis, psoriasis, eczema, and acne. Cop this ingredient in a toner, face mist, serum, or mask if you have an inflammatory condition or are prone to acne.
Skin Care Acids: Trichloroacetic Acid
Trichloracetic acid — aka TCA — is derived from vinegar and is often used as an in-office chemical peeling agent. It exfoliates the top layer of the skin and Dr. Wesley notes that its benefits include the reduction of dark spots, fine lines, and thin superficial skin growths (such as keratoses and warts). Skin that’s left with dark marks after a breakout as well as photodamaged skin may also benefit from TCA. However, those with skin of color need to be careful with TCA, as “depending on the strength, too much exfoliation or irritation could result in discoloration or dark marks from the treatment itself,” warns Dr. Wesley.
Skin Care Acids: Mandelic Acid
Mandelic acid is an AHA naturally occurring in bitter almonds. Yep, you read that right. It’s known for its antiseptic and brightening properties, and is best for those with dull complexions and acne-prone skin, and is deemed one of the safest options for darker skin tones. “Mandelic acid has the ability to slough away the dead skin cells that can clog pores and cause acne breakouts,” explains Dr. Polla. “In addition, it has moisturizing effects that keep the skin hydrated and soft, allowing blemishes to heal better.” While there may be some redness or slight irritation following the use of mandelic acid, it’s typically better tolerated than glycolic acid.
Skin Care Acids: Gluconolactone
Gluconolactone is a non-irttitating polyhodroxyacid (or PHA) that has a similar effect to glycolic acid, but is milder and offers the added benefit of antioxidant and anti-aging properties, says Dr. Engelman. Because it attracts and binds water, it provides effective hydration for dry skin types. Gluconolactone can be found in peels, serums, and moisturizers, and is safe for sensitive skin types including rosacea-prone skin and those prone to atopic dermatitis.
Skin Care Acids: Kojic Acid
Kojic acid is a skin-lightening acid that’s derived from fermented rice. “Kojic acid is used to treat pigmentation disorders,” says Dr. Polla. “It inhibits the activity of the tyrosinase, the enzyme responsible for the production of melanin in the skin. It also has antioxidant and anti-inflammatory properties.” If your skin has uneven pigmentation (either from sun damage or acne scars), kojic acid may help as it can lighten a targeted area without removing the normal melanin from your skin tone (and can be used by all skin tones).
The ingredient can be found in spot treatments, peel pads, and serums, but one thing to note is that kojic acid is a known irritant that has the potential for causing contact dermatitis, erythema, transient redness, and stinging. Dr. Polla notes that it’s not generally considered a “clean” ingredient and is strictly regulated in Europe, so speak to your dermatologist before incorporating kojic acid into your routine.