There’s no doubt that topical collagen creams hydrate the skin. However, it’s not scientifically possible for collagen to be absorbed or penetrate the skin from the outside. “Collagen is a huge molecule that sits on the surface of the skin and cannot be absorbed into the dermis,” board-certified dermatologist Dendy Engelman, M.D., previously explains to mbg.

She adds, “When applied topically, it is not possible for collagen to penetrate, which is why we use other actives to stimulate collagen production.” Think retinol, glycolic acid, etc. She confirms that any product that claims this benefit is simply a marketing tactic. Board-certified dermatologist Deanne Mraz Robinson, M.D., seconds the falsehood: “Unfortunately, the hype behind topical collagen is just that: hype,” she says. 

We should note that the beauty industry evolves every day with new biotechnology to help mimic standard ingredients found in nature. Recently, formulators have discovered a few biotech ingredients that can, in fact, boost your skin’s natural collagen production when applied topically—and brands have started to market these as topical “vegan collagen.” But not every brand uses these high-tech innovations (plus, the tech is still pretty young), so we advise you to do your research.

Still, most topical collagen serums haven’t been researched enough yet to confirm major skin aging benefits. But what about ingestible forms? Luckily, there’s promise in that department.* Here’s what we know: