What it is
This is a sulfated polysaccharide extracted from certain red seaweeds and long used as a food and cosmetic gelling agent. In formulas it thickens the water phase, forms soft gels, and helps stabilize emulsions and suspensions of pigments or mineral filters. In sun care it contributes to a cooling, jelly-like texture and to even, stable spread.
Safety & warnings
Topically, carrageenan is a large molecule that is not meaningfully absorbed through intact skin and is generally well tolerated with low irritation potential. It is not a known fragrance allergen and is not an oil, so comedogenicity is not a typical concern.
Origin & sourcing
Natural, derived from red marine algae (seaweed) by hot aqueous extraction.
Questions everyone asks
Where does carrageenan come from?
It is extracted from red seaweed and has a long history of use as a natural thickening and gelling agent.
Why is it used in sunscreen?
It thickens and stabilizes the formula and helps create a smooth, gel-like, easy-to-spread texture.