Ingredient
Polyisobutene
What is Polyisobutene?
Polyisobutene is a synthetic polymer derived from isobutylene, commonly used in cosmetics and personal care products. It is a rubber-like, smooth substance that provides a glossy finish and elasticity.
It is mainly used as a film-forming agent and as an emollient to create a protective barrier on the skin and lips. The health evidence on polyisobutene is limited, but it is generally considered safe for topical use in cosmetics.
When you see polyisobutene on a label, it is typically present to enhance the texture and longevity of the product, especially in lip care and makeup products.
Commonly found in: Lip Care, Makeup, Skincare Products, Hair Styling Products
Polyisobutene is permitted for use in cosmetics and personal care products in the US with no specific restrictions.
Current research shows polyisobutene is safe for use in cosmetics, though long-term studies are limited.
Polyisobutene is synthetic and not animal-derived, generally considered vegan-friendly.
Sources: FDA Cosmetic Ingredient Review
Scout's take
Polyisobutene is a synthetic polymer used as a binder and film-forming agent in lip balms. While it is safe for topical application, it is not intended for ingestion and may cause irritation in sensitive individuals.
More from Scout's analyses
Standard formulation ingredient — neither beneficial nor harmful at typical use.
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