Po
Polybutene
PolybuteneBarrier
A thick, tacky polymer that leaves a high-shine, cushiony, long-wearing film. It’s what makes many lip glosses glossy.
What it does
It also adds body to a product. It’s there for feel and finish.
The evidence, graded
expert consensusUS safety reviewers (2020) assessed a group of polyenes, polybutene among them, which products use mainly to form a film or thicken oils. In people, a lipstick with 20% caused no irritation, and patch tests of products with 3.1–50% caused no allergy. In rabbits, products with more than 15% caused mild irritation. They judged it safe as used.Burnett 2020 · International Journal of Toxicology ↗
Graded per the methodology: strong · moderate · emerging · expert consensus. A weak source on a strong claim gets the weaker label.
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