What it is
Hydroxypropyl starch phosphate is a chemically modified starch in which hydroxypropyl groups and phosphate cross-links are added to improve stability and performance over native starch. It thickens water phases and helps adjust texture, often contributing a soft, powdery, low-tack skin feel. In sunscreens it is valued for reducing greasiness and improving the sensory finish.
Safety & warnings
Hydroxypropyl starch phosphate has a good tolerability profile and is regarded as gentle and non-irritating at cosmetic use levels. It is not a known allergen or comedogen.
Origin & sourcing
Plant-derived and modified. It is made from natural starch, commonly from corn, potato, or tapioca, that is treated with propylene oxide and a phosphate reagent.
Questions everyone asks
What does hydroxypropyl starch phosphate do for skin feel?
It thickens the formula while leaving a soft, dry, powdery finish, which helps reduce the greasy feel common in sunscreens.
Is it natural?
It is derived from natural starch but is chemically modified, so it is best described as plant-based and processed.