Even if you don’t consider yourself a skin-care connoisseur, you’ve probably heard of hyaluronic acid. In the past few years, it has become one of the most famous ingredients in the cosmetics industry, beloved for its ability to plump and moisturize the skin. It can be found in dozens of popular, dewy-inducing serums, from Glossier’s Super Bounce (beloved by makeup artist Katie Jane Hughes) to Dr. Barbara Sturm’s Hyaluronic Serum (which basically every celebrity is obsessed with, from Bella Hadid, to Kim Kardashian West, to Victoria Beckham).

But what if I told you there was a cheaper, lesser-known, ultra-moisturizing ingredient that works just as well as hyaluronic acid? Enter glycerin, hyaluronic acid’s budget-friendly sister. Much like HA, glycerin is a humectant, meaning it attracts and retains water. And its low molecular weight means it’s able to penetrate extra deep into the skin. I called dermatologist Dr. Shereene Idriss to ask if she felt glycerin held up to hyaluronic acid, and she went a step further and said she prefers it — it’s an unsung skincare hero that, she says, is better at increasing skin hydration, minimizing water loss, and protecting the skin from irritation. (Because it’s so conditioning, the ingredient can leave your skin feeling a bit sticky afterward. As someone with ultra dry skin, this has never bothered me — but if you have an oilier skin type it’s something to consider.)