“Vitamin F is not a vitamin in the traditional sense of the word,” says board-certified dermatologist Hadley King, M.D. “It’s actually a term for two fats, alpha-linolenic acid (ALA) and linoleic acid (LA).” The two acids that come together to create vitamin F are naturally occurring healthy fatty acids that are your newest answer to plump, glowing skin. Keep reading to learn more. Vitamin F can be found in various foods like almonds, chia seed, and even egg yolks. And if you’re an oil lover, you’ll find this fatty acid combo in rosehip, sunflower, chia, and argan oils. But when it comes to applying topically, vitamin F helps to strengthen and protect the skin barrier. “These fatty acids are part of the seal that sits in cracks between cells in the outer skin layer,” says board-certified dermatologist Joshua Zeichner, M.D. In simpler terms, he explains that vitamin F is similar to the grout that sits between your bathroom tiles. “Natural fats maintain the integrity of the outer skin layer,” he says. Essentially, these fats seal in moisture and keep environmental aggressors out.