Ferulic acid. Hyaluronic acid. Lactic acid. Salicylic acid. Sometimes it can seem like we’re in chemistry class rather than browsing the skin care aisle looking for a good serum. It’s easy to assume that all acids are pretty much the same, but they’re not. And knowing the differences between the acids used in skin care is essential for targeting complexion concerns.
It is true that acids are common ingredients in beauty products because they help improve skin. Dr. Vermén M Verallo-Rowell, founder of VMV Hypoallergenics, explains that skin care acids induce necrosis of cells, aka cell turnover. This causes older cells to shed and new ones to quickly grow below, thus improving the texture of skin. But different acids target specific skin care concerns depending on the molecular size of the acid and its strength. Some target fine lines and wrinkles, while others treat acne or hyperpigmentation.
It may initially seem overwhelming trying to figure out the difference between AHAs and BHAs, but it’s not necessary to get into the scientific details of each acid. As long as you can remember the best acids for your skin type and complexion concerns, that’s really all that matters. (Unlike in school, there’s no quiz at the end.) Here are the key details about the different skin care acids.
Ascorbic acid is a synthetic version of vitamin C that has antioxidant benefits, according to board-certified dermatologist Dr. Joyce Imahiyerobo-Ip. It’s a good option for those looking for brighter skin and to stimulate collagen production. Verallo-Rowell points out that ascorbic acid is unstable once the container is open, meaning it will lose its potency over time.
Try: NIOD Ethylated L-Ascorbic Acid 30% Network, $70 at NIOD or Drunk Elephant C-Firma Day Serum, $80 at Sephora
Those with redness often fear harsh skin care ingredients like acids. There’s no need to be scared of azelaic acid. Imahiyerobo-Ip says that the acid can benefit those with redness, rosacea and acne. It’s also suitable for treating hyperpigmentation and melasma.
Try: The Ordinary Azelaic Acid Suspension 10%, $7.90 at The Ordinary or HydroPeptide Redefining Serum, $130 at DermStore
Citric acid is an alpha hydroxy acid (AHA) that is derived from citrus fruits, hence the name. It’s an antioxidant-rich acid that is good for preventing premature aging. Imahiyerobo-Ip adds that it’s also suitable for acne-prone or sun-damaged skin because it exfoliates to brighten brown spots. Concerned about it being harsh? Verallo-Rowell says that it’s mild and less acidic than the other AHAs.
Try: REN Glycol Lactic Radiance Renewal Mask, $55 at Sephora or Juice Beauty Green Apple Age Defy Serum, $55 at Ulta
Ferulic acid is an antioxidant that helps fight free radicals and the signs of aging. It’s typically used in combination with other actives like ascorbic acid, vitamin C or vitamin E. Those with sensitive skin should use it with caution. Ferulic acid is found in the seeds of oranges and apples and in the cell walls of plants like apples and oranges. When purchasing a product with the ingredient, try to see how much processing it has been through as too much can make the acid less effective.
Try: Ole Henriksen Perfect Truth CC Crème Broad Spectrum SPF 30, $36 at Ole Henriksen or Dr. Dennis Gross Skincare Ferulic + Retinol Serum Triple Correction Eye Serum, $68 at Nordstrom
Glycolic acid is a versatile AHA that can help improve the appearance of spots, scars and wrinkles while making skin more radiant. Plus, it will shrink pores. Imahiyerobo-Ip says that it’s one of the best acids for aging skin.
Try: NeoStrata Foaming Glycolic Wash, $40 at NeoStrata or TULA Pro-Glycolic 10% pH Resurfacing Gel, $34 at Space.NK
Most people have probably heard of hyaluronic acid used in moisturizers. That’s because it’s a superb water-retaining hydrater, according to Verallo-Rowell. It’s ideal for aging skin as it improves the appearance of fine lines and softens and plumps skin. Imahiyerobo-Ip suggests looking for products that contain hyaluronic acid and vitamin C to help the product penetrate skin.
Try: The Ordinary Hyaluronic Acid 2% + B5, $6.80 at The Ordinary or SkinCeuticals Hyaluronic Acid (H.A.) Intensifier Serum, $98 at SkinCeuticals
Lactic acid is a key ingredient to remember for sensitive skin types. The acid exfoliates and softens fine lines and wrinkles, but in a less irritating way than other acids says Imahiyerobo-Ip.
Try: Sunday Riley Good Genes All-In-One Lactic Acid Treatment, $158 at Sephora or Kate Somerville ExfoliKate Intensive Exfoliating Treatment, $24 at Nordstrom
Mandelic acid is ideal for brightening and lightening skin. According to Verallo-Rowell, the acid comes from grapes and has a fairly high acidity, but it’s less irritating than glycolic acid. It’s a common peel ingredient, so look for it in at-home and professional peels.
Try: Peter Thomas Roth PROfessional Strength 40% Triple Acid Peel, $88 at Sephora or Bakel Brightening Serum, $150 at Space.NK
Those with dry skin will want oleic acid on their radar. It’s a moisturizing essential fatty acid that is found in animal and vegetable sources, such as olive oil. The acid has antioxidant and anti-inflammatory properties that can help psoriasis, eczema and even seborrheic dermatitis (excessive scalp dandruff), according to Imahiyerobo-Ip.
Try: StriVectin Advanced Acid Repair Oleic Rapid Recovery Milk, $79 at Ulta or Erno Laszlo Sensitive Cleansing Oil, $58 at Sephora
Even those new to acids will probably have heard of salicylic acid. It’s the hero acid for those with acne-prone skin because it penetrates pores to reduce sebum. What’s more, it can remove discoloration and improve skin tone over time and can also be effective for treating rosacea. Verallo-Rowell points out that it’s the only beta hydroxy acid (BHA) and it’s not for those who are pregnant, breastfeeding or allergic to aspirin. Those with darker complexions should also watch out because it can sometimes cause irregular lightening or darkening of skin.
Try: Paula’s Choice RESIST Advanced Pore-Refining Treatment 4% BHA, $36 at Paula’s Choice or Kiehl’s Blue Herbal Spot Treatment, $18 at Kiehl’s