Ingredient review
Bis-C16-20 Isoalkoxy TMHDI/PEG-90 Copolymer
INCI: BIS-C16-20 ISOALKOXY TMHDI/PEG-90 COPOLYMER
A synthetic film-former that helps products stay put and resist water, but offers no active skincare benefit.
In plain English
This is a man-made ingredient that forms a thin, invisible film on your skin or hair. Think of it like a clear, flexible seal that helps sunscreen, makeup, or hair products stay in place longer and resist sweat or water. It doesn't moisturize or treat your skin—it's purely a performance ingredient.
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
Bis-C16-20 Isoalkoxy TMHDI/PEG-90 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 Bis-C16-20 Isoalkoxy TMHDI/PEG-90 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 reacting a modified diisocyanate with polyethylene glycol and long-chain alkoxy groups. It is designed to form a flexible, water-resistant film on the skin or hair surface.
How it works
When applied, the copolymer molecules spread out and link together as the solvent evaporates, creating a continuous, flexible film. This film physically blocks water and oil from easily washing away the product, and it helps other ingredients (like sunscreen filters or pigments) stay evenly distributed.
Pros
Boosts wear time
Creates a flexible film that helps sunscreen and makeup resist water, sweat, and rubbing, so you don't have to reapply as often.
Lightweight feel
Despite being a film-former, it typically dries down without a heavy or sticky residue, making it comfortable for daily wear.
Cons and cautions
No skincare benefit
This ingredient doesn't hydrate, soothe, or repair skin—it's purely a performance additive, so it adds no active value to your routine.
Potential tightness
On very dry or compromised skin, the film can feel slightly tightening or uncomfortable, especially if layered under multiple products.
Best for
- Anyone wanting longer-lasting sunscreen or makeup
- People who need water-resistant protection for swimming or sweating
Use caution if
- Those who prefer minimal-ingredient, water-only routines
Usage tips
Safety summary
Considered safe for topical use at typical concentrations. The polymer is too large to penetrate the skin, so it stays on the surface. Rare reports of mild irritation or tightness in sensitive individuals.
Research notes
Limited independent studies on this specific copolymer, but it is chemically similar to other PEG-based film-formers that have a long history of safe use in cosmetics. Safety assessments rely on analog data and formulation-level testing.
Common label clues
- Typical concentration
- 0.5% to 5%
- Regulatory status
- Approved for use in cosmetics in the US, EU, and other major markets. No specific concentration restrictions are common, but formulators typically use it at low levels to avoid a heavy feel.
- Common uses
- Sunscreens, Long-wear makeup, Water-resistant formulas, Hair styling products
- Environmental note
- As a synthetic polymer, it is not biodegradable and may accumulate in the environment. Some regions are beginning to scrutinize non-biodegradable film-formers in rinse-off products.
Good to know
- This ingredient is often found in combination with other film-formers and silicones for a smooth, silky feel.
- It is not water-soluble, so it won't wash off with water alone—double cleansing is recommended.
Common questions
What is Bis-C16-20 Isoalkoxy TMHDI/PEG-90 Copolymer in beauty products?
This is a man-made ingredient that forms a thin, invisible film on your skin or hair. Think of it like a clear, flexible seal that helps sunscreen, makeup, or hair products stay in place longer and resist sweat or water. It doesn't moisturize or treat your skin—it's purely a performance ingredient.
What does Bis-C16-20 Isoalkoxy TMHDI/PEG-90 Copolymer do in a beauty product?
When applied, the copolymer molecules spread out and link together as the solvent evaporates, creating a continuous, flexible film. This film physically blocks water and oil from easily washing away the product, and it helps other ingredients (like sunscreen filters or pigments) stay evenly distributed.
Is Bis-C16-20 Isoalkoxy TMHDI/PEG-90 Copolymer safe for most people?
Considered safe for topical use at typical concentrations. The polymer is too large to penetrate the skin, so it stays on the surface. Rare reports of mild irritation or tightness in sensitive individuals.
Who should be careful with Bis-C16-20 Isoalkoxy TMHDI/PEG-90 Copolymer?
Those who prefer minimal-ingredient, water-only routines
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.