Take a walk down the beauty aisle and you'll see a never-ending array of products that claim to turn back the clock on aging skin and fix everything from acne to dark spots. Many of those products rely on naturally derived acids to work their magic. But which is right for you?
The key is knowing what each acid does and what skin type and issues it can improve. To break it down, we spoke with Dr. Sejal Shah, a dermatological surgeon and consultant with RealSelf, and Dr. Alan Parks, founder of DermWarehouse, who discussed how different acids affect the skin.
The latest buzzword in beauty is hyaluronic acid. While most acids have a drying effect on the skin, hyaluronic acid actually hydrates. This ingredient has the ability to hold up to 1,000 times its own weight in water, deeply moisturizing skin while plumping and filling in fine lines and wrinkles. "Look for hyaluronic acid high on an ingredients list for the best results," says Shah.
You're probably already familiar with this common skin care ingredient as it's found in many products, particularly those formulated to control acne. Salicyclic acid is a beta hydroxy acid that is derived from willow bark. It's good at loosening dead skin cells and cleaning out clogged pores, but it also can be a little harsh on dry skin so it's best for those with an oily complexion or as an on-the-spot product to control breakouts.
Derived from sugar, glycolic acid's small molecules help to exfoliate the skin, lightening dark spots, reducing fine lines and smoothing the skin's texture. "Glycolic contains the smallest molecules of the AHAs [alpha hydroxy acids] and can therefore penetrate the skin deeply and easily," says Parks. "It is very effective for many skin concerns such as wrinkles, acne (and acne scars), oiliness and dullness of the skin."
As the name implies, lactic acid is derived from milk, so it's gentler on the skin than some of the other acids on this list. Its moisturizing properties make it a good choice for people with sensitive skin who want to even out their skin tone and reduce fine lines. Shah recommends lactic acid for those who want to improve skin texture and tone, reduce hyperpigmentation, and revitalize dull, dry skin.
Retinoids are superheros of the skin care world. These vitamin A derivatives can do everything from minimizing fine lines and wrinkles to reversing sun damage to increasing skin elasticity. While prescription formulas yield the best solutions, over-the-counter products containing retinol can still give noticeable results.
Ascorbic acid, aka vitamin C, is a go-to ingredient for anyone looking to improve the health of their skin. It's an antioxidant that can neutralize the free radicals that promote aging while reducing fine lines and brightening skin tone. "I believe this is one ingredient that's worth splurging on," says Shah. "Any and every skin type can benefit from Vitamin C." Look for products packaged in a brown bottle because ascorbic acid degenerates when exposed to sunlight.
The large molecules of mandelic acid allow it to penetrate skin more slowly and gently than other alpha hydroxy acids such as glycolic acid. "This ingredient accelerates cell turnover and will help with signs of aging and evening the skin tone," says Parks. Shah adds that mandelic acid's anti-bacterial properties make it a good choice for treating acne, particularly for those with sensitive skin.
Derived from grapes, tartaric acid is good for exfoliating skin and stimulating collagen production. "It will help with lines and wrinkles, and also stimulates collagen production to make the skin look firmer," says Parks.
Azelaic acid works by decreasing swelling, making it a good choice for conditions such as rosacea. It's an anti-bacterial that is also good at unclogging pores so it can be used to treat acne as well. According to Shah, azelaic acid is generally tolerated by all skin types.
Oleic acid is the most abundant fatty acid found in human tissue. It is also found in many animal and vegetable fats and oils. It's great for moisturizing and soothing skin conditions such as eczema, rosacea and psoriasis. But it's also occlusive and and may promote the formation of acne so, according to Shah, it's not a good choice for acne-prone individuals.
This omega-6 acid has anti-inflammatory and astringent properties. "Low levels of linoleic acid have been shown in the sebum of individuals with acne and one study found that applying free linoleic acid reduced the size of comedones, so it is thought that linoleic acid may improve acne." says Shah.
According to Parks, lipoic acid helps to repair and regenerate skin cells, making your skin look younger and firmer. It can reduce puffiness around the eyes and the face area, even skin tone, and decrease pore size. "This ingredient will give your skin a glow," says Parks.
Kojic acid is derived from fungi and fermented foods. "Kojic acid is a powerful skin lightening agent and therefore is very effective for treating hyperpigmentation," says Parks. He adds that it is also a good exfoliator and can be used to remove dead skin cells. But be careful if you have sensitive skin as kojic acid can be irritating to some skin types.
Malic acid is a natural substance commonly found in many fruits, such as apples. This alpha hydroxy acid helps shrink pore size, diminish the appearance of fine lines, exfoliate the skin to improve tone and texture, and also will help with hyperpigmentation.
Found naturally in the seeds of fruits such as apples and oranges, as well as in certain nuts and grains, such as rice, wheat, peanuts and soybeans, ferulic acid is an anti-aging ingredient that can help prevent and reverse sun damage and wrinkles. It's not great for those with sensitive skin or for those with allergies to foods containing ferulic acid.