Dermatologists set the record straight about this skincare ingredient.
- Jennifer Herrmann, MD, FAAD, is a board-certified dermatologist based in Beverly Hills.
- Joshua Zeichner, MD, is a board-certified dermatologist and the director of cosmetic research in dermatology at Mount Sinai Medical Center.
Type of ingredient: Humectant, solvent, emollient, and preservative.
Main benefits: Attracts water and locks it into the skin.
Who should use it: In general, anyone who is looking for extra hydration and smoothness of the skin.
How often can you use it: Propylene glycol is a safe ingredient to use regularly, provided that you do not have an allergy to it.
Works well with: Because it has so many functions, there isnâ€™t a specific list of ingredients that it works well with.
Don't use with: Propylene glycol works well with most, if not all, ingredients.
What Is Propylene Glycol?
Propylene glycol is a colorless, odorless liquid that is completely water- soluble. According to Herrmann, it is synthetic and produced by adding water to propylene oxide, which is derived from petroleum products. Propylene glycol is used as a humectant, a preservative, a solvent, or an emollient in a wide variety of formulas, such as creams, lotions, serums, shampoos, and many other types of personal care products.
Benefits of Propylene Glycol for Skin
Propylene glycol has many functions and is used in a multitude of skincare products for its versatility. Here are its main functions:
- Attracts water: Zeichner says at low concentrations, propylene glycol acts like a humectant, which means it binds water and pulls in hydration to the outer skin layer. When used in cosmetic products, it helps give the skin a hydrated, dewy appearance.
- Boosts other ingredients: Because of its binding properties, propylene glycol can enhance the delivery of other active ingredients into the skin.
- Lightly moisturizes: Herrmann adds that as a humectant, it also offers moisturizing benefits and smoothes the skin with a light, non-sticky feel.
- Addresses visible signs of aging: The humectant property also makes it a useful ingredient for dry or aged skin. "As we age, our skin loses a component called Natural Moisturizing Factor (NMF) and subsequently dries out, which emphasizes wrinkles and contributes to flaking and roughness," Herrmann says. "Propylene glycol helps bind water from the environment, helping to counter the water loss that accompanies aging."
- Enhances penetration: Zeichner says it helps the active ingredients of cosmetics penetrate through the skin, which in turn makes them more effective.
- Prevents water loss: As an emollient, propylene glycol forms a protective film on the skin that prevents water loss and helps to smooth and soften skin, according to Herrmann.
- Is safe for acne-prone skin: Because itâ€™s not oily, Herrmann says itâ€™s also ideal for those with acne.
- Helps lessen the appearance of spots over time: Due to its moisturizing properties, propylene glycol nourishes the skin, helping to lessen the appearance of marks and acne spots.
Propylene Glycol vs. Ethylene Glycol
Though commonly confused for each other, propylene glycol and ethylene glycol are structurally different, and it's important to distinguish the two. According to Herrmann, ethylene glycol (an ingredient used in antifreeze) is considered to be toxic and harmful, while propylene glycol is not.
Side Effects of Propylene Glycol
While propylene glycol actually should be avoided for some people, it's not for the scary reasons you might have read about online. Because propylene glycol is derived from petroleum, many have concerns that it is carcinogenic and can be toxic when used in skincare. But according to Zeichner, cosmetic-grade petrolatum is different than commercial petroleum and is not carcinogenic, and similarly, neither is propylene glycol. Herrmann adds, "Many safe products and chemicals can be derived from toxic parents, but what matters for safety is the final chemical structure form. She continues, "Unless contamination is an issue, being derived from petroleum doesnâ€™t make it dangerous. Its final form is considered non-carcinogenic and is found in many topical cosmetic products."
While there's no truth to these more serious claims, propylene glycol isn't totally innocuous either. As Herrmann points out, it was the American Contact Dermatitis Society's Allergen of the Year in 2018. "If you are developing a red, itchy rash where youâ€™re applying your product, you may have an allergy to one of its ingredients," Zeichner says. "Propylene glycol is often the culprit." Herrmann adds that those with eczema might be more likely to be sensitive to the ingredient, and for those patients, she always suggests patch tests or trying new products on a small area of the skin on the inner wrist before applying them more broadly.
In general, however, products containing propylene glycol are fine to use for most people. "Based on what we know today and based on years of use in cosmetic products, propylene glycol is a safe ingredient to use, provided that you do not have an allergy to it," Zeichner says.
How to Use It
As Herrmann explains it, because propylene glycol is in so many products, there isnâ€™t one way to use it. Instead, she recommends using products containing the ingredient as directed by your dermatologist or as instructed by the manufacturers. As far as how often you should use it or how much should be used, Herrmann says propylene glycol is considered safe, even when consumed in relatively large quantities.
The Best Products With Propylene Glycol
Paulaâ€™s Choice is known for its effective products and no-BS approach to skincare, so it should come as no surprise that this acne treatment is one of Herrmann's top picks. â€œPropylene glycol helps increase hydration without being oily and helps the benzoyl peroxide penetrate pores more deeply and effectively,â€ Herrmann says.
Another favorite of Herrmann's, this oil-free cleanser contains 8.5 percent glycolic acid to exfoliate and brighten skin, while camellia and licorice extracts relieve any redness and inflammation. â€œPropylene glycol keeps it light and ideal for blemish-prone skin," she adds.
Dermatologists, beauty editors, and skinfluencers swoon over SkinCeuticals' products, and Herrmann highly suggests giving this serum from the line a try if you haven't yet. â€œItâ€™s packed with antioxidants to help keep skinâ€™s DNA healthy and boost collagen production,â€ Herrmann says. â€œIt also contains light alpha- hydroxy acids that lightly exfoliate and maximize radiance.â€ Did we mention it contains propylene glycol to boost its penetration?
Another favorite of dermatologists and beauty editors alike, this moisturizer uses a combination of ceramides, sodium hyaluronate, and propylene glycol to replenish the skin's moisture levels and seal that hydration for healthy, supple skin.
You can count on the combination of ferulic acid, retinol, and licorice root extract in this product (which made ishonest's list of the best eye serums) to stop the damage caused by extrinsic aging that can result in wrinkles and discoloration. And with propylene glycol, these ingredients can better penetrate the skin and work more effectively.
It might not be a skincare product, but this formula is one of Herrmann's top product recommendations and deserves a mention on this list anyway. Much like it does for your skin, propylene glycol works to hydrate the hair sans sticky feel. "Propylene glycol helps this shampoo hydrate hair by binding water and prevents its evaporation," Herrmann says. "Because itâ€™s light, it also doesnâ€™t cause buildup like some oil-containing shampoos."
Yes. Because it helps bind water to the skin, it can be extra beneficial for those who struggle to retain moisture.
Because itâ€™s not an oily ingredient, itâ€™s also beneficial for those with acne- prone skin.
Propylene glycol is most commonly used in creams, lotions, and serums.
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