Trehalose

If you’ve ever wondered why some tiny sugars can help a plant survive a desert and your skin survive central heating, meet trehalose. It’s a naturally occurring disaccharide — basically a sugar made of two glucose molecules — with a tidy, symmetrical structure that gives it surprisingly good stability. You may also see the names trehalose dihydrate or, in less friendly chemistry-land, trehalose dimycolate, which is a very different molecule found in certain bacteria. And yes, if you were wondering about trehalose pronunciation, it’s usually said TREH-uh-lohz.

In skincare, trehalose works mainly as a humectant, meaning it helps bind water and support hydration at the skin’s surface. That’s the short version of the benefits of trehalose for skin: it can help reduce that tight, dry feeling and make formulas feel more cushioning and comfortable. It’s often used in moisturizers, serums, masks, cleansers, and hair products because it plays nicely with other hydrating ingredients. The good news is that trehalose is safe for most people when used topically, and it’s not the kind of ingredient that tends to cause drama. If you’re looking for the best trehalose in a product, the answer is usually the one paired with glycerin, panthenol, or other barrier-friendly ingredients, because trehalose shines as part of a team rather than as a diva solo act.

Trehalose also shows up in eye care, where trehalose eye drops are used to help soothe dry, stressed eyes by supporting the surface tear film. In studies, trehalose-containing eye drops have been used for dry eye symptoms with encouraging results, especially in people dealing with irritation from environment or contact lenses. That said, if you’re searching for the health benefits of trehalose or asking how much trehalose per day to take, that’s a food-and-supplement question, not a skincare one. As a food ingredient, trehalose is found in some mushrooms, honey, and certain processed foods, and people sometimes ask how to use trehalose in baking because it can help with moisture retention and browning. But unlike in cosmetics, eating it is a separate story, and whether trehalose is bad for you or how to take trehalose depends on your overall diet and medical context. For skin, though, its job is refreshingly simple: help hold onto water and make your formula feel a little less thirsty.

Trehalose is a naturally occurring sugar found in plants, fungi, and some microorganisms, where it helps cells hold onto water and stay stable in dry or stressful conditions. In skincare, it’s used as a humectant, meaning it attracts and helps retain moisture at the surface of the skin. That makes it a useful ingredient for supporting a softer, smoother, more comfortable feel, especially in formulas aimed at dehydration or environmental stress.

For skin, trehalose can help reduce that tight, parched feeling by supporting hydration without feeling heavy or greasy. It’s also used in hair products, where it can help improve softness and reduce the look of dryness or frizz by helping strands retain moisture. People with dry, dehydrated, or easily stressed skin often appreciate it, but it can also fit well into lightweight daily routines for most skin types.

Caveat: trehalose is a supportive ingredient, not a miracle fix, and its effects depend on the full formula it’s in. If your skin is very dry, it usually works best alongside other moisturizing ingredients like glycerin, hyaluronic acid, or emollients.