PEG-90

PEG-90 is a polyethylene glycol—a synthetic polymer derived from petroleum. In skincare, it serves dual purposes: as a humectant (a moisture-binding ingredient) and as a solvent that helps dissolve and stabilise other ingredients within a formula.The number in its name refers to its molecular weight; PEG-90 is a relatively small molecule in the PEG family, which influences how it behaves on and in the skin.

PEG-90 is hygroscopic, meaning it has an affinity for water molecules. When applied to skin, it attracts moisture from the environment and from deeper skin layers, drawing it to the surface where it can plump and soften the outer layer (stratum corneum).Within a formula, it dissolves and suspends other ingredients, allowing them to be delivered consistently and remain stable over time. This dual role—both active ingredient and formulation workhorse—makes it a versatile addition to many skincare products.

PEG-90 is typically a supporting ingredient rather than a starring role in formulations, so you don't need to target a specific concentration. Use products containing it as directed by the brand. It pairs well with other humectants like glycerin or hyaluronic acid for enhanced hydration, and works across most product types—serums, moisturisers, cleansers—without special application considerations.

PEG-90 is generally well-tolerated and has a long safety record in skincare. Hypersensitivity to polyethylene glycols is rare, though individuals with known PEG sensitivity should check product labels or patch test first.