Ingredient review
Hydrogenated Polyisoprene Crosspolymer
INCI: HYDROGENATED POLYISOPRENE CROSSPOLYMER
A safe synthetic polymer that improves product texture, water resistance, and wear without clogging pores.
In plain English
This is a man-made rubber-like ingredient that helps cosmetic products feel smooth, spread evenly, and stay in place longer. It is often used in mascaras and eyeliners to make them waterproof and smudge-proof, and in moisturizers to give a silky, non-greasy feel. Because it is a large molecule, it sits on the surface of the skin or hair without being absorbed, so it is unlikely to cause irritation or breakouts.
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 Polyisoprene Crosspolymer 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 Polyisoprene Crosspolymer.
- 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 crosslinked polymer derived from polyisoprene (a type of synthetic rubber) that has been hydrogenated to make it more stable and compatible with cosmetic oils and silicones.
How it works
When applied, it forms a thin, flexible film on the skin or lashes that helps other ingredients stay put and resist water and sweat. It also thickens the product's texture, giving it a luxurious, non-sticky feel.
Pros
Enhances wear and water resistance
Helps mascaras and eyeliners stay put through sweat, tears, and humidity, reducing the need for touch-ups.
Non-comedogenic and low irritation
Because it is a large polymer that does not penetrate the skin, it is very unlikely to clog pores or cause irritation, making it suitable for sensitive skin.
Cons and cautions
Not biodegradable
As a synthetic polymer, it does not break down easily in the environment, which is a concern for eco-conscious consumers.
Can feel heavy in high amounts
If used at very high concentrations, it may leave a tacky or heavy feel on the skin or lashes, though this is rare in well-formulated products.
Best for
- Anyone looking for long-wearing, water-resistant eye makeup
- People who prefer non-greasy, silky moisturizers
Use caution if
- Those who prefer entirely natural or biodegradable ingredients
Usage tips
Safety summary
Hydrogenated Polyisoprene Crosspolymer is considered safe for use in cosmetics. It has a low irritation and comedogenic risk, and no significant safety concerns have been reported in normal use.
Research notes
Research on this specific polymer is limited, but it is chemically similar to other safe synthetic film-formers. Regulatory reviews (e.g., CIR) have not flagged any safety issues for hydrogenated polyisoprene or its crosspolymer forms.
Common label clues
- Typical concentration
- 0.5% to 5%
- Regulatory status
- Approved for use in cosmetics in the US, EU, and most other regions. No concentration restrictions are typically imposed.
- Common uses
- Mascara, Eyeliners, Lip products, Serums, Moisturizers
- 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
- Hydrogenated Polyisoprene Crosspolymer is often used as a silicone alternative in 'silicone-free' formulas.
- It is considered safe by major cosmetic regulatory bodies including the FDA and the European Commission.
Common questions
What is Hydrogenated Polyisoprene Crosspolymer in beauty products?
This is a man-made rubber-like ingredient that helps cosmetic products feel smooth, spread evenly, and stay in place longer. It is often used in mascaras and eyeliners to make them waterproof and smudge-proof, and in moisturizers to give a silky, non-greasy feel. Because it is a large molecule, it sits on the surface of the skin or hair without being absorbed, so it is unlikely to cause irritation or breakouts.
What does Hydrogenated Polyisoprene Crosspolymer do in a beauty product?
When applied, it forms a thin, flexible film on the skin or lashes that helps other ingredients stay put and resist water and sweat. It also thickens the product's texture, giving it a luxurious, non-sticky feel.
Is Hydrogenated Polyisoprene Crosspolymer safe for most people?
Hydrogenated Polyisoprene Crosspolymer is considered safe for use in cosmetics. It has a low irritation and comedogenic risk, and no significant safety concerns have been reported in normal use.
Who should be careful with Hydrogenated Polyisoprene Crosspolymer?
Those who prefer entirely natural or biodegradable 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.