Ingredient review
Steareth-100/PEG-136/HDI Copolymer
INCI: STEARETH-100/PEG-136/HDI COPOLYMER
A synthetic polymer that helps products stay put on skin, but offers no active skincare benefits.
In plain English
This is a man-made ingredient that forms a thin, flexible film on your skin. It helps other ingredients spread evenly and makes products more water-resistant, so your sunscreen or foundation lasts longer. Think of it like a gentle, invisible glue that holds the product together on your face.
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
Steareth-100/PEG-136/HDI 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 Steareth-100/PEG-136/HDI 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 created by combining steareth-100 (a fatty alcohol derivative), PEG-136 (a polyethylene glycol chain), and HDI (hexamethylene diisocyanate). It is a high-molecular-weight polymer designed to create a film on the skin.
How it works
When applied, the copolymer molecules link together to form a continuous, flexible film over the skin. This film helps lock in other ingredients, reduces water wash-off, and gives a smooth, even feel. It also thickens the product slightly, making it easier to apply.
Pros
Boosts water resistance
Helps sunscreens and makeup stay effective even when you sweat or swim, reducing the need for frequent reapplication.
Improves product feel
Creates a silky, smooth texture that spreads easily and doesn't feel heavy or sticky on the skin.
Cons and cautions
No active benefit
This ingredient only provides texture and film-forming properties—it doesn't hydrate, soothe, or treat skin concerns.
May require double cleansing
Because it forms a film, it can be stubborn to remove with just water or gentle cleansers, often needing an oil-based first step.
Best for
- Anyone wanting longer-lasting sunscreen or makeup
- People who swim or sweat and need water-resistant products
Use caution if
- Those who prefer minimal-ingredient or all-natural routines
- People with very sensitive skin that reacts to synthetic polymers (rare)
Usage tips
Safety summary
Steareth-100/PEG-136/HDI Copolymer is considered safe for topical use in cosmetics. It has low irritation and comedogenic potential. No significant safety concerns have been raised by regulatory or scientific panels.
Research notes
Limited independent research exists specifically on this copolymer. Safety is inferred from its chemical class (polyurethanes and PEG derivatives), which have a long history of safe use in cosmetics. The Cosmetic Ingredient Review (CIR) has evaluated similar polymers and found them safe.
Common label clues
- Typical concentration
- 0.5% to 5%
- Regulatory status
- Approved for use in cosmetics in the US (FDA), EU (CosIng), and many other regions. No known restrictions at typical use levels.
- Common uses
- Sunscreens, Water-resistant lotions, Makeup primers, Long-wear foundations
- Environmental note
- As a synthetic polymer, it is not biodegradable. However, it is used in small amounts and is not considered a major environmental concern compared to microplastics.
Good to know
- This polymer is often used in combination with other film-formers for extra durability.
- It is considered safe for use in cosmetics by major regulatory bodies at typical concentrations.
- The 'PEG' part means it's water-soluble, helping the film rinse off more easily than some silicones.
Common questions
What is Steareth-100/PEG-136/HDI Copolymer in beauty products?
This is a man-made ingredient that forms a thin, flexible film on your skin. It helps other ingredients spread evenly and makes products more water-resistant, so your sunscreen or foundation lasts longer. Think of it like a gentle, invisible glue that holds the product together on your face.
What does Steareth-100/PEG-136/HDI Copolymer do in a beauty product?
When applied, the copolymer molecules link together to form a continuous, flexible film over the skin. This film helps lock in other ingredients, reduces water wash-off, and gives a smooth, even feel. It also thickens the product slightly, making it easier to apply.
Is Steareth-100/PEG-136/HDI Copolymer safe for most people?
Steareth-100/PEG-136/HDI Copolymer is considered safe for topical use in cosmetics. It has low irritation and comedogenic potential. No significant safety concerns have been raised by regulatory or scientific panels.
Who should be careful with Steareth-100/PEG-136/HDI Copolymer?
Those who prefer minimal-ingredient or all-natural routines People with very sensitive skin that reacts to synthetic polymers (rare)
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.