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It's no secret that the beauty community has a tendency to take part in "cancel culture" when it comes to ingredients that we used to love (or at the very least, be okay with) and, when backed by science, this is rightfully so—our skin, a permeable gateway to our bodies, is precious and should be treated with the utmost care. One ingredient largely being dropped from product formulas as a result of the backlash is propylene glycol, and alternative ingredients are rising to take its place. Enter: Butylene glycol, a slightly larger chemical compound, which is found to be far less irritating. With expert insight from Morgan Rabach, MD, a board-certified dermatologist and co-founder of LM Medical in NYC and cosmetic chemist Ron Robinson of BeautyStat.com, we take a further look into the pros and cons of butylene glycol to figure out why it's used as a substitute for propylene glycol. Keep reading to find out everything there is to know about the ingredient that’s becoming increasingly popular in your skincare.
Type of ingredient: Humectant, solvent, and emollient
Main benefits: Retains moisture, dissolves ingredients, and improves application.
Who should use it: In general, anyone looking for a way to effectively moisturize their skin.
How often can you use it: Butylene glycol is safe for daily use for those who do not have an allergy to it or very sensitive skin.
Works well with: As a solvent, butylene glycol works well with ingredients that are not water-soluble and are difficult to dissolve.
Don't use with: Butylene glycol works well with most, if not all, ingredients.
What Is Butylene Glycol?
Butylene glycol is an organic alcohol derived from petroleum and is water-soluble. For cosmetic purposes, it comes in a liquid form and is found in countless skincare products such as cleansers, moisturizers, and masks, as well as makeup and haircare products. Butylene glycol has many different roles in skincare formulations (it's a humectant, solvent, and emollient) and is used as an alternative to the more commonly known controversial ingredient propylene glycol.
Benefits of Butylene Glycol for Skin
As a multifunctional ingredient in cosmetics, butylene glycol does a little bit of everything:
- Attracts water: Robinson says butylene glycol is a humectant, which means it binds water and pulls in hydration to the outer layer of the skin.
- Enhances penetration: By breaking down hard-to-dissolve active ingredients, butylene glycol improves penetration, which, as a result, helps the product perform more effectively.
- Conditions and smooths: In addition to being a humectant, butylene glycol can also function as an emollient by creating a barrier on the skin, which prevents water loss and softens and conditions.
Butylene Glycol vs. Propylene Glycol
Since both of these ingredients are derived from petroleum products, available in the form of a colorless liquid, and used in product formulations for the same reasons, it's easy to get them confused. According to Robinson, butylene glycol and propylene glycol are in the same class of compounds and function similarly as well. However, Robinson says unlike butylene glycol, propylene glycol is considered to be much more irritating to consumers. In fact, propylene glycol was even named the American Contact Dermatitis Society's Allergen of the Year in 2018. For that reason, he says many brands have removed it from their formulas and turned to alternatives, such as butylene glycol, instead.
What you've heard about both ingredients being used in antifreeze is true, but neither is considered to be toxic (unlike another closely related ingredient that is also used in antifreeze called ethylene glycol—this ingredient is considered to be harmful and should definitely be avoided). Despite concerns and skepticism around butylene and propylene glycol, the EWG rates propylene glycol at 3 out of 10 (10 being the most hazardous) on their “danger scale” and butylene glycol at the lowest possible hazard rating: 1.
Side Effects of Butylene Glycol
It's important to note that just because an ingredient is derived from petroleum doesn't automatically make it dangerous to use. In its final chemical structure form, butylene glycol is considered safe for cosmetic use. Studies show that butylene glycol is an ingredient with low-levels of irritation, and the occurrence of allergic contact dermatitis is rare, although still a possibility. It can be irritating to people with very sensitive skin, and these skin types should avoid this ingredient if it leads to allergic rashes, according to Rabach and Robinson. If you do experience irritation or an itchy rash, discontinue use of the product and consult a physician. With formal patch testing, your dermatologist or allergist can determine if butylene glycol is the cause of your reaction.
How to Use It
Because butylene glycol is such a versatile ingredient and is found in so many products, there isn’t one certain way to apply it. In general, Rabach says butylene glycol is safe for daily use. As far as when to use products containing the ingredient, how often to use it, or how much should be used, consult your dermatologist or follow the directions specified on the product label.
The Best Products With Butylene Glycol
This booster is one of our favorite products for post-inflammatory hyperpigmentation because it's packed with all the right ingredients to tackle an acne breakout and calm inflammation: azelaic acid, salicylic acid, licorice root extract, and allantoin. Butylene glycol is another key ingredient worth noting because not only does it offer hydrating benefits, but it also works to help active ingredients better penetrate the skin.
This Byrdie Skincare Award-winning face cream is not exactly cheap, but it certainly delivers in results. Unlike some moisturizers, which simply feel nice when applied, this cream is as scientific as it is luxurious (it triggers your own stem cell regeneration process). The formula is packed with skin-loving ingredients, like argan and avocado oils, antioxidants, and essential fatty acids as well as butylene glycol to keep it all flowing nicely.
This dry mask is infused with vitamins, peptides, and oils, and the humectant properties of butylene glycol also make it a notable ingredient in this magically hydrating mask. The best part? Unlike most sheet masks that are tossed after one use, you can wear this one three times before opening a new one. Once you give it a try, you'll see why it's one of our favorites.
Backed by beauty editors, YouTubers, and skincare Redditors, Tatcha is the beauty industry's worst kept secret. This gel-to-foam cleanser from the brand is beloved for its use of silk-derived amino acids to gently and effectively cleanse while ingredients like Japanese luffa fruit exfoliant and butylene glycol simultaneously hydrate the skin.
This product is a cult-favorite for good reason, and the recently updated formulation has launched it to icon status. It still has the lightweight feel and sheer tinted coverage that made it famous, but it now contains vitamins C and E and is available in 20 shades. And thanks to the butylene glycol helping to spread the hard-to-dissolve pigments, the formula has an even, consistent application.
If you have yet to find a retinol that doesn't completely destroy your skin barrier in the process, give this dermatologist-approved night cream a try. It uses moisturizing and skin-soothing ingredients allantoin, niacinamide, and butylene glycol to counteract the irritation caused by the powerful retinoid and lactic acid blend.
Anyone with dry skin knows that washing your face is a sensitive topic. Most cleansers strip the skin and leave it feeling tight and flaky, but this gel cleanser soothes as it removes all traces of makeup, dirt, and debris. The viscosity reducer butylene glycol makes this cleanser easy to apply, which is great because like us, you won't want to stop using it.