What it is
Proteoglycans are molecules consisting of a protein core attached to glycosaminoglycan sugar chains, a structure that holds large amounts of water. In cosmetics this water-binding capacity is used to provide humectant and conditioning benefits, helping the formula feel hydrating and smooth on the skin. In sunscreens it functions as a supporting moisturizing ingredient rather than as a sun filter.
Safety & warnings
Proteoglycan is generally well tolerated as a conditioning ingredient. As with any protein-containing biological ingredient, individuals with known sensitivities to the source material should be aware, but it is not associated with notable irritation or comedogenicity at cosmetic use levels.
Questions everyone asks
What does proteoglycan do in skincare?
It binds water thanks to its sugar-protein structure, acting as a humectant and conditioning agent that helps the formula feel hydrating and smooth.
Is proteoglycan a sun filter?
No. It is a moisturizing and skin-conditioning ingredient, not a UV filter, and is included to support the texture and feel of the product.