Lactic Acid: Hydrate And Brighten In One

Ingredient Investigation

Lactic Acid: Hydrate And Brighten In One

By Chrissy Carrano

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Lactic acid is an alpha hydroxy acid (AHA), a category of acids named for its molecular structure. It's naturally derived from milk, though more often than not in skincare, its synthetically and identically produced. Through its exfoliating action, lactic acid is used to swipe away dead skin cells, brighten complexion, lighten hyperpigmentation, and improve the appearance of fine lines. Different than other acids, it's also moisturizing, which is why you'll see it show up across skincare products.
How it Works

Acid exfoliants work by breaking the bonds that hold dead skin cells together, clearing the way for newer, fresher skin cells to emerge. Among the family of AHAs tapped in skincare (lactic, glycolic, malic, tartaric, and mandelic), lactic is one of the gentlest due to its larger molecular size—meaning it doesn't penetrate as quickly or deeply.

Lactic acid can serve double duty in a product as both an exfoliant and hydration booster. 

Make it Routine

Most commonly, lactic acid shows up in exfoliants, serums, or moisturizers.

As an exfoliant, the impact of lactic acid comes down to the concentration. Most at-home products have a lower percentage of lactic acid, making them safe and effective chemical exfoliants. It's a great starter AHA exfoliant, especially for more reactive skin types.

The take-home version of this peel uses lactic acid to exfoliate and brighten the skin.

Lactic acid lives in this dry powder dermafoliant for a gentle exfoliation when water is added.

When lactic acid appears in a serum or moisturizer, it's largely there for its hydrating properties (while lightly exfoliating). You'll often find lactic acid in super hydrators meant to help with conditions like eczema, psoriasis, and keratosis pilaris (that bumpy texture commonly on the back of arms).

This retinol cream calls upon lactic acid to lightly exfoliate, making way for retinol and peptides to fight visible signs of aging.

Wait—One More Thing!

You may know lactic acid from exercise talk. After a solid sprint or heavy workout, a buildup of lactic acid, the exact same chemical compound, is the culprit behind that burn you feel.

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