12 Dec 10 Confusing Moisturizer Ingredients, Decoded
Let us clear things up for you.
Vaseline made it famous, but you’ll find petrolatum in other moisturizers too. It’s known as an occlusive, which is an ingredient that forms a barrier on the outermost layer of your skin to hold water in, sort of like a topcoat of nail polish, says Ranella Hirsch, MD, FAAD, a dermatologist in Cambridge, Massachusetts. Petrolatum is a great choice for trapping in the moist air after a steamy shower at night, but it could be too greasy to use during the day. “I wouldn’t use it in the morning, because you wouldn’t put makeup over it,” says Dr. Hirsch.
Because they’re occlusive, oils like mineral, coconut, and avocado oil sit on top of the skin while sealing in moisture. But that barrier could be bad news for acne-prone skin, says Tina West, MD, PC, dermatologist and founder of skincare center The West Institute. “Look for something that’s oil-free—so no mineral oil, no silicones,” she says. “It’s not specifically what’s in in, it’s more what to stay away from. You want a lighter moisturizer, something that won’t clog pores or cause an occlusive barrier.” But if you’re not worried about breakouts, occlusives could be useful if your skin is losing moisture outside factors, like dry air in a heated office, because they’ll trap moisture that would otherwise evaporate out, says Dr. Hirsch.
Lanolin, an oil extracted from sheep’s wool, is an occlusive, but it also acts like an emollient, meaning it can help fill in the space between cells. “If you think of them being like a cobblestone road, for example, the emollient will work by going between those little cracks and giving the skin a smoother texture,” says Dr. West.
Both occlusive and emollient, dimethicone-based moisturizers feel nice to apply because its silicone base makes it feel more velvety. “They go on as a smooth product and don’t create that thick gooiness,” says Dr. Hirsch. “You want to use it in daytime because it’s more cosmetically elegant.”
Ceramides are a type of lipid, which are the molecules that appear naturally in your skin to help hold in water. Using them as a moisturizer ingredient can make that water retention more active, helped along by their fatty acids. “We call it waxy because it fills in the cracks between cells and the surface, but it won’t necessarily feel waxy,” says Dr. West. This emollient is particularly helpful for people with eczema or very dry skin, she says.
As a humectant, glycerin attracts water into skin cells, helping your skin bring in more moisture. “You’re getting something that fundamentally attracts water to the skin rather than keeping it from getting lost,” says Dr. Hirsch. Humectants like glycerin are ideal moisturizers if your skin is dry from traveling.
Another humectant, hyaluronic acid attracts moisture from the inner layer of skin cells, but it also attracts moisture from the air if it’s humid enough, says Dr. West. Because it can evaporate, it’s good to pair with an occlusive like dimethicone to help seal in the moisture, says Dr. Hirsch. “Get a product like hyaluronic acid to absorb the water and then something to help retain the water for a double boost,” she says. “It’s a wonderful trick when it gets very dry with the season change.”
Some people avoid propylene glycol because it isn’t natural, though there’s no evidence showing it will cause any harm. “It’s like how some people would rather buy something at Whole Foods than CVS because it’s natural, but it doesn’t necessarily mean it’s better for you,” says Dr. West. Seek out another humectant like hyaluronic acid if you try to avoid synthetic products, though propylene glycol is FDA-approved and shouldn’t cause a reaction unless you happen to be allergic.
Urea is a humectant that’s also somewhat exfoliating, but that extra function might not be as good as it sounds. “In general, we don’t lack exfoliation—it’s just a common myth that’s out there,” says Dr. Hirsch. “The truth is most people could stop exfoliating, and no harm, no foul.” You already scrub off some of those dead cells just by washing your face, and over-exfoliating could leave your skin raw. If you have particularly oily skin, though, you might want to a moisturizer with urea in your regimen, says Dr. Hirsch.
Lactic acid and urea both tend to be found in moisturizers marketed for people with extra dry skin because they help improve the skin’s ability to hold water. “They’re good for people who need a molecule to help break down the skin barrier,” says Dr. West.