Ingredient review
Hydrogenated Butadiene/Isoprene/Styrene Copolymer
INCI: HYDROGENATED BUTADIENE/ISOPRENE/STYRENE COPOLYMER
A synthetic polymer that helps makeup last longer and resist water, but offers no skincare benefit.
In plain English
This is a man-made plastic-like ingredient that forms a flexible, invisible film on your skin or lashes. It's what helps your mascara stay put through tears or rain and keeps your lipstick from smudging. Think of it as a clear, breathable sealant that locks makeup in place without feeling heavy or sticky.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is useful, but some claims depend heavily on the formula.
Risk flags are low for most users, though the finished product can still irritate.
- Source
- synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Hydrogenated Butadiene/Isoprene/Styrene Copolymer is generally a lower-concern ingredient when the full formula suits your skin.
Plain-English read
Treat this as a practical screening step before you compare products that contain this ingredient.
- Step 1Start with the score, then check the irritation and clogging risk before judging Hydrogenated Butadiene/Isoprene/Styrene Copolymer.
- Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
- Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.
Score terms in plain English
Irritation risk
lowLess likely to sting, burn, or bother most users, though sensitive skin can still react.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
moderateThere is useful support, but formula details and claim strength still matter.
What it is
A synthetic copolymer made from hydrogenated butadiene, isoprene, and styrene monomers. It is a rubber-like material that is chemically modified (hydrogenated) to be more stable and less reactive, making it safe for cosmetic use.
How it works
When applied, the copolymer molecules spread into a thin, even layer. As the solvent (water or oil) evaporates, the polymer chains link together to form a flexible, water-resistant film. This film physically holds pigments and other ingredients in place, improving wear time and preventing smudging or fading.
Pros
Excellent wear time
Helps makeup stay put for 12+ hours without smudging or fading, even in humid conditions.
Water-resistant barrier
Forms a protective film that resists water, sweat, and tears, ideal for mascara and eyeliners.
Cons and cautions
No skin benefits
This ingredient is purely functional—it doesn't hydrate, soothe, or protect the skin in any way.
Removal can be tricky
Because it forms a strong film, you may need an oil-based or dual-phase makeup remover to fully cleanse it off.
Best for
- Anyone wanting long-lasting makeup
- People with oily skin who need extra wear time
- Those who live in humid or rainy climates
Use caution if
- People who prefer minimal or 'clean' ingredient lists
- Those with very sensitive eyes who may react to film-forming ingredients
Usage tips
Safety summary
Considered safe for cosmetic use at typical concentrations. Low irritation and comedogenic risk. No known systemic toxicity from topical application. However, it is a synthetic polymer with no environmental biodegradability.
Research notes
Limited peer-reviewed research specifically on this copolymer, but it is structurally similar to other widely studied film-forming polymers used in cosmetics. Safety assessments by industry panels (e.g., CIR) have concluded it is safe for topical use.
Common label clues
- Typical concentration
- 1% to 10% depending on product type
- Regulatory status
- Approved for use in cosmetics globally. In the EU, it is listed under Annex II as a permitted film former. The US FDA considers it safe when used as intended.
- Common uses
- Mascara, Eyeliners, Lipsticks, Long-wear foundations, Sunscreens
- Environmental note
- As a synthetic polymer, it is not biodegradable and may contribute to microplastic pollution. Some brands are moving toward biodegradable alternatives.
Good to know
- Hydrogenation makes the polymer more stable and less likely to cause irritation compared to non-hydrogenated versions.
- This ingredient is common in 'tubing' mascaras that form tiny tubes around each lash for easy removal with warm water.
Common questions
What is Hydrogenated Butadiene/Isoprene/Styrene Copolymer in beauty products?
This is a man-made plastic-like ingredient that forms a flexible, invisible film on your skin or lashes. It's what helps your mascara stay put through tears or rain and keeps your lipstick from smudging. Think of it as a clear, breathable sealant that locks makeup in place without feeling heavy or sticky.
What does Hydrogenated Butadiene/Isoprene/Styrene Copolymer do in a beauty product?
When applied, the copolymer molecules spread into a thin, even layer. As the solvent (water or oil) evaporates, the polymer chains link together to form a flexible, water-resistant film. This film physically holds pigments and other ingredients in place, improving wear time and preventing smudging or fading.
Is Hydrogenated Butadiene/Isoprene/Styrene Copolymer safe for most people?
Considered safe for cosmetic use at typical concentrations. Low irritation and comedogenic risk. No known systemic toxicity from topical application. However, it is a synthetic polymer with no environmental biodegradability.
Who should be careful with Hydrogenated Butadiene/Isoprene/Styrene Copolymer?
People who prefer minimal or 'clean' ingredient lists Those with very sensitive eyes who may react to film-forming ingredients
Research sources
Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.