Everything You Need To Know About Acids In Skin Care


As children, we’re convinced acids are of the green, gloopy, boiling type; designed to melt our skin right off. But while that isn’t exactly too far from the truth, now that we’re older, we’ve come to learn that certain acids, when used in regulated doses can infact do wonders for our skin.

From melting off stubborn dead skin cells and even banishing serious skin issues like acne scars, Into The Gloss came up with a guide to the most common types of acids used in exfoliating, moisturizing, zit-zapping, and everything in between:

Acetic Acid

It’s vinegar. Wouldn’t recommend using it on its own, but tons of people use Apple Cider Vinegar, which pairs acetic and malic acid, to tone the face, remove scalp build-up, etc. Use with caution.

Azelaic Acid

An antioxidant that occurs naturally in the skin; It’s derived from yeast, grain, and/or barley.

Azelaic acid hardly gets any mainstream love, but has been traditionally prescribed for people with rosacea. It also helps fight inflammation, redness, pimples, and swelling.

Azelaic acid is classed as a doic (dicarboxylic) acid, basically meaning it’s antibacterial and brightening.

If you have the mentioned skin problems above, it could be a godsend.

Carbolic Acid

Also known as phenol, carbolic acid is not for the faint of heart—it’s a heavy-duty exfoliator that’s linked to a handful of hazards, like respiratory toxicity and skin irritation.

These kinds of claims typically don’t take into account the very small dosage used in cosmetic products, but are helpful to keep in mind.

Citric Acid

Citric acid when in powder form is an alpha hydroxy acid that sloughs off dead skin at the surface. It’s a relatively weak chemical exfoliant—so weak, that it’s hardly found in exfoliating products on the market.

However, because of its gentle composition, it’s a great raw acid to practice mixing your own exfoliant at home if you’re into that—at least before graduating to lactic. But maybe check it out with a professional before brewing away with your DIYs.


Enter polyhdroxy acids (PHAs).

PHAs, or polyhydroxy acids, aren’t very prevalent in chemical exfoliators, but PHAs are a gentler class of exfoliant than AHAs or BHAs. Products with gluconolactone, one of the most prevalent PHAs; is praised for being effective without the redness, peeling, and sensitivity that comes with heavier-duty acids. But it also doesn’t penetrate as deep as they do.

Glycolic Acid

Glycolic is everybody’s favorite oily skin saver and general clarifying agent, basically the big boss of all alpha hydroxy acids.

Alpha hydroxy acids work on the surface of your skin, while beta hydroxy acids penetrate a little deeper. AHAs are also water-soluble and recommended for dry and normal skin types. Glycolic and lactic are the most popular in this class of acid.

Nevermind that glycolic is in almost every chemical exfoliant out there, but there’s tons of research backing up its reputation as one of the most effective acids on the market.

Lactic Acid

The ‘secret’ ingredient in the Instagram and Youtuber skin care guru raved about Sunday Riley Good Genes.

Another alpha hydroxy acid, and a good pair to the glycolic acid. It’s a popular alternative to glycolic because it works in the same way, but it’s milder, and works more to moisturize skin while it exfoliates. Luckily, it does not smell like milk gone bad, although this beloved skin care ingredient is sometimes derived from it.

Linoleic Acid

Linoleic and oleic acids (which usually go hand-in-hand) are not exfoliating acids. However, they can be used to treat acne, as many cases of acne have been linked to an imbalance of linoleic and oleic acids in skin.

Linoleic and oleic acids are classed as omega-rich “fatty acids”, which tons of dermatologists and aestheticians recommend for healthy skin.

Malic Acid

If evening out your skin tone is your main concern, then this acid might do the job for you.

It is an AHA that lacks the exfoliating power of glycolic and lactic acids, but is more popular than citric acid as malic acid is also used to adjust the pH of a product towards acidity, but it tends to pop up particularly in brightening exfoliants.

Mandelic Acid

While most mandelic peels have the acid in higher concentration, don’t let it scare you off as the acid itself is a gentler AHA than most and a popular acid for sensitive skin and rosacea. It’s antibacterial, meaning it’s great for acne troubles too, and exfoliates without brightening like other AHAs, making it a favorite of those of us with deeper skin tones.

Oleic Acid

Kin to linoleic acid.

Retinoic Acid

Aaah, the dermatologist favorite when your zits first start acting up in teenhood.

Retinoic acid is actually what you’re shopping for when looking for a retinoid—when vitamin A and it’s deritatives are applied to your skin, it has to be converted to retinoic acid in order to actually work.

The stronger the vitamin A, the shorter the conversion time. And as you know, retinol works for everything—acne, fine lines, sun damage, what-have-you.

Salicylic Acid

The mainstream zit killer, this beta hydroxy acid penetrates deeper than AHAs because they’re oil-soluble, journeying to the root of your pores instead of operating at the surface level. This makes them ideal for treating oily and acneic skin, and an extremely effective heavy-duty exfoliant for everyone.

Tartaric Acid

Something you might not have heard about on those face-splashing commercials.

It’s  an unlikely favorite as an active exfoliant because it’s not as stable as AHAs, but is popular for pH balancing needs.

But here’s a fun thing: tartaric acid is found in wine and creates things called “wine diamonds”, crystals that spontaneously generate at the bottom of the bottle. How fun. We love you, tartaric acid! But we’d rather take glycolic, thank you very much.


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