Glycoproteins

In skincare, glycoproteins are typically used as film-forming, conditioning/humectant biopolymers at low concentrations, and they are generally well-tolerated with low rates of irritant reactions in patch testing compared with surfactants, acids, or preservatives. However, because they are larger bio-derived proteins/complexes, there is a non-zero potential for sensitization or reactivity in highly compromised eczema skin depending on source and impurities, so I do not score them as inert. Safety Notes: In consumer skincare, “glycoproteins” are typically supplied as biotechnology-derived or marine-derived active solutions and are often used at very low levels (about 0.001–0.05%) in leave-on serums/creams and eye products where they function as conditioning/skin-feel or “firming” actives. Higher-end or high-strength OTC products (especially premium serums, masks, and some post-procedure-style soothing formulations sold direct-to-consumer) can push glycoprotein actives toward ~1–5% when the ingredient is available as a high-solids active or used as a primary featured complex; above this, cost, tack/film formation, and stability/bioburden constraints usually limit further increases. Rinse-off products generally sit toward the lower end due to brief contact time and cost-benefit considerations.