What Is Gluconolactone? All About the Next Big — Super-Gentle — Skin Exfoliant

What is gluconolactone?

Before we get into it, it’s helpful to have a short refresher on the powerhouse chemical-exfoliant family known as hydroxy acids (it’s relevant, promise). First up: alpha hydroxy acids (AHAs), which are water-soluble and often added to toners, peels, and cleansers to help maintain an even skin tone and texture. The ever-popular glycolic and lactic acids also fall into this category. Next up are beta hydroxy acids (BHAs), which are oil-soluble, making them great for controlling sebum. The one you’re most likely familiar, salicylic acid, is commonly used to help unclog pores and treat acne.

Finally, there’s poly-hydroxy acids (PHAs), which are sometimes called “next-generation” AHAs. PHAs behave much like AHAs, but are considered gentler by dermatologists for a very science-y reason (BRB, making Bill Nye proud). “PHAs are very similar in action to AHAs, but are much larger molecules than the typical AHAs,” Dr. Cheung explains. (And yes, “poly” means many, so their larger molecular structure is explained right there in the name.) To put it simply, “PHAs are ‘next-generation’ due to their versatility and tolerability,” explains the derm.

Gluconolactone is—you guessed it—a poly-hydroxy acid. But part of the reason you may not have heard of it (aside from its hefty 14-letter name) is that it tends to play more of a background role to other, showier active ingredients. Still, it should be in your starting skincare lineup—and here’s why.

What are the benefits of gluconolactone?

It all comes down to two words: gentle and versatile. “PHAs are larger molecules than AHAs, so they don't penetrate as deep for more gentle exfoliation and less irritation,” says Dr. Cheung. Gluconolactone also plays well with other ingredients, such as vitamin C and AHAs like glycolic acid—rendering it even more effective in the process. “PHAs are often combined with other active ingredients to boost penetration,” explains Dr. Cheung.

But what makes gluconolactone such an underrated skincare gem is that exfoliation is the first in a long list of benefits. “Gluconolactone is a humectant, so it moisturizes and soothes the skin while revealing smoother, brighter skin,” explains Dr. Cheung. It can also help fight free-radical damage, which may lead to fine lines and other signs of aging. “It has antioxidant and anti-inflammatory properties, and helps to prevent collagen weakening and loss of elasticity from glycation [a process where sugars weaken collagen],” says Dr. Cheung.

Are there any side effects?

“Gluconolactone is not known to cause irritation, and helps to strengthen the skin's barrier function,” says Dr. Cheung. You can thank gluconolactone’s large molecule size for its soothing nature and tolerability compared to other hydroxy acids. Still, because it is often paired with other—perhaps more irritating—active ingredients, there is always a possibility that a skincare product can cause a reaction. Be sure to do a patch test whenever trying a new product, especially if you have sensitive skin. And if you’re also using a product containing gluconolactone along with another exfoliant (either chemical or physical), check with your dermatologist to see if it’s safe to use them together.

How to use gluconolactone in your skincare routine

So long as you aren’t using it in addition to other, harsher exfoliants, gluconolactone can be incorporated into your daily routine. However, you may want to decrease your frequency if you have certain skin conditions. “Sensitive skin types with rosacea or eczema can add gluconolactone twice a week to their regimen,” Dr. Cheung advises.

Because of gluconolactone’s extensive résumé, you can find it in just about every type of skincare product. In cleansers and toners, it gently exfoliates dead skin cells and evens skin tone and texture. In serums and moisturizers, its humectant qualities attract water molecules to boost hydration. Gluconolactone can generally be used any time of day, too. “PHAs can be used both a.m. and p.m. since they are so gentle and help the penetration of your active daytime and nighttime ingredients,” says Dr. Cheung.

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