Ingredient Spotlight: Glycolic Acid

Glycolic acid is one of those dermatological skincare ingredients that’s seemingly everywhere: from cleansers to serums to peels — in both at-home and in-office strengths. Dermatologists recommend it for both face and body, for a variety of skin types and concerns.

So what’s so great about glycolic acid? To get a grasp on exactly why this popular AHA is so powerful, we combed through research and then went straight to the source: Dr. Sandra Lee (aka Dr. Pimple Popper), who shares some of her favourite ways to use this potent ingredient.

Glycolic acid used in skincare for exfoliating

4 minute read



What is glycolic acid?

The most widely-studied alpha hydroxy acid, glycolic acid (also known as hydroxyacetic acid) is typically derived from sugar cane. It’s the simplest of the water-soluble alpha hydroxy acids, with the lowest molecular weight. Because it’s such a small molecule, glycolic acid is capable of penetrating deep into the epidermis, and depending on concentration, even into the dermis below.

First synthesized in the mid-19th century, today it’s available in a wide variety of concentrations ranging from in-office peels (up to 70%) to over-the-counter cleansers, lotions, and treatments (up to 10%).

What does glycolic acid do for skin?

With benefits for blemish-prone and ageing skin alike, it’s no wonder so many dermatologists endorse glycolic acid. This AHA is capable of addressing a variety of concerns for both face and body, including:

How does glycolic acid work?

Let’s take a closer look at exactly how glycolic acid accomplishes such an impressive collection of skincare benefits.

It exfoliates dead cells

You’ve probably heard that glycolic acid is a great exfoliator. But what does this mean, exactly?

Time for another biology lesson: remember that your skin is made up of several layers, including the outermost epidermis — which in turn is composed of 5 layers.

Keratinocytes (aka skin cells) are created deep within the skin and are pushed to the surface as new cells are born beneath. As the keratinocytes move toward the surface, they begin to die and flatten into corneocytes — the cells that make up skin’s tough outermost later known as the stratum corneum. The corneocytes are held together by extracellular proteins called desmosomes, which act like a glue holding the dead cells together.

Still with us? Because here’s the beauty part: glycolic acid weakens those desmosomes — essentially “ungluing” the corneocytes from each other and accelerating their shedding (aka desquamation). Once those dead cells slough off, the fresher, newer skin underneath is exposed. This has the dual benefit of reducing dullness and creating a perfect canvas for additional skincare treatments and/or makeup application.

It stimulates collagen production

Studies have shown that glycolic acid can actually increase collagen — which is the protein primarily responsible for giving skin its firm structure. So how does it work?

Here’s where this AHA’s extraordinary penetrating ability comes into play. In higher concentrations (typical of those found in medium to deep peels), glycolic acid molecules can reach all the way down into the dermis. This is where you’ll find fibroblasts: the special connective tissue cells that make collagen.

Glycolic acid stimulates fibroblast proliferation — aka it makes more fibroblasts, which in turn leads to more collagen. And since collagen production naturally slows as we age, getting a boost from glycolic acid definitely helps in the well-ageing department.

It boosts skin’s natural hydration

Ever heard of glycosaminoglycans? Maybe you know them as mucopolysaccharides. If that’s not ringing a bell, here’s a hint: think molecules like hyaluronic acid, found in connective tissue, that lubricate skin and joints.

Studies show that applying glycolic acid to the skin leads to increased levels of these hard-to-say substances that are essential for keeping skin plump and youthful. So while you can certainly incorporate both glycolic acid and hyaluronic acid products into your skincare routine, know that just using AHA will also increase your body’s own production of natural hydrators.

SLMD Glycolic Acid Body Scrub

How to use glycolic acid in your skincare routine

According to dermatologist Dr. Sandra Lee (aka Dr. Pimple Popper), adding glycolic acid into your regimen is fairly straightforward — even if you’re already using other potent actives.

Here are a few of her favourite ways to use glycolic acid for face and body:

  • With salicylic acid. Combining water-soluble AHA with oil-soluble BHA is an ideal way to get pores deep-down clean. Start with SLMD Salicylic Acid Cleanser and follow up with your preferred glycolic acid product weekly, as tolerated.
  • With lactic acid. Another small AHA, lactic acid works well with glycolic acid to slough away keratin buildup. Try them together in SLMD Glycolic Acid Body Scrub, which smooths and exfoliates.

Dr. Lee’s last word

One of the reasons I recommend chemical exfoliants is because they’re typically very well tolerated by most skin types. Glycolic acid, an alpha hydroxy acid, is time-tested and very effective. You can use it on both the face and the body — and it’s particularly good for dry, rough skin and ingrown hairs. For ageing skin, it’s proven to stimulate collagen production which can help your skin feel firmer. As always, make sure you’re using sunscreen (even in wintertime), as glycolic acid will make you more sun sensitive.

—Dr. Sandra Lee

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