What it is
Isostearoyl hydrolyzed collagen is produced by attaching a branched isostearic acid chain to the amino groups of hydrolyzed collagen peptides, giving the water-loving peptide a fatty, oil-compatible tail. This amphiphilic structure lets it sit at oil-water interfaces, where it helps stabilize emulsions and impart a smooth, conditioned feel to the skin. In sun-care formulas it typically appears at low levels as a texture and feel modifier rather than as a primary active.
Safety & warnings
Acylated hydrolyzed proteins of this type are generally well tolerated at the low levels used in cosmetics. Because the peptide backbone is animal-derived, it is not suitable for vegan formulations, and individuals with known sensitivities to specific protein sources may wish to take note. It is not a recognized fragrance allergen.
Origin & sourcing
Semi-synthetic. The collagen portion is animal-derived (commonly bovine or fish) protein that has been broken down into smaller peptides, then chemically modified with isostearic acid, a branched fatty acid.
Questions everyone asks
Is isostearoyl hydrolyzed collagen vegan?
No. The collagen portion is derived from animal protein, so it is not considered vegan or suitable for strictly plant-based formulations.
What does it do in a sunscreen?
It acts mainly as a skin-conditioning agent and mild emulsifier, helping stabilize the formula and lend a smooth, soft feel rather than providing UV protection.