Trehalose is a simple sugar made of two glucose units linked together, and it is found in nature's toughest survivors, like mosses, brine shrimp, and desert microbes that can dry out completely and then spring back to life once rehydrated. It survives that ordeal because trehalose surrounds delicate cell parts and essentially locks in place where water used to be, protecting them from damage while the organism is dried out. On human skin, that same water holding ability translates into a genuine hydration boost.
A 2026 study found that a formula containing trehalose measurably improved skin hydration and reduced water loss through the skin compared to the same formula without it. Because trehalose is such a stable, sturdy molecule, it also holds up well to the heat involved in manufacturing skincare products, something more fragile ingredients cannot always handle.
Trehalose References
Trehalose in an Emulsion Based Carrier: Effects on Skin Hydration and Transepidermal Water Loss, Cosmetics (MDPI), 2026
Trehalose Is a Versatile and Long Lived Chaperone for Desiccation Tolerance, Current Biology, 2014
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Best
Ingredients with the most rigorous and convincing evidence. These are the standouts backed by consistent findings across independent, peer reviewed clinical research.. When we call an ingredient Best, it has earned that distinction through genuine, reproducible proof that it improves skin.
Good
Reliable, well tolerated ingredients that do their job without complaint. They may not carry the headline benefits of a Best rated active, but they hydrate, stabilize a formula, or support the ingredients around them in ways that make a real difference in how a product performs and feels.
Average
Ingredients that are perfectly safe and serve a clear function, typically as an emollient, thickener, or filler, but do not offer any meaningful skin benefit beyond that basic job. Not a red flag, just not a reason to choose one product over another.
Bad/Worst
Ingredients with documented potential to irritate skin, disrupt the barrier, or trigger sensitization in some users, often synthetic fragrance, drying forms of alcohol, or certain essential oils. Not automatically a dealbreaker for every skin type, but worth knowing about before you commit to a product.
