Ingredient review
Bis-Isobutyl PEG-15/Amodimethicone Copolymer
INCI: BIS-ISOBUTYL PEG-15/AMODIMETHICONE COPOLYMER
A gentle silicone polymer that helps products spread smoothly and resist water, but may not suit those avoiding all silicones.
In plain English
This is a man-made silicone ingredient that forms a thin, flexible film on your skin or hair. It helps lotions and creams glide on easily, makes hair feel silky and less frizzy, and can help makeup or sunscreen stay put longer, even in water. Think of it as a lightweight, breathable coating that doesn't feel heavy or greasy.
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-Isobutyl PEG-15/Amodimethicone 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-Isobutyl PEG-15/Amodimethicone 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 modified silicone polymer where a water-loving PEG chain and a conditioning amodimethicone segment are combined. The isobutyl groups help it mix well with oils and other ingredients, making it versatile in formulas.
How it works
When applied, the copolymer spreads into an even, ultra-thin layer that adheres to skin or hair. The amodimethicone part provides slip and conditioning, while the PEG section allows water to pass through, so the film doesn't trap moisture or feel sticky. This helps products feel lightweight and resist washing off from sweat or water.
Pros
Lightweight feel
Unlike some heavy oils or waxes, this copolymer spreads into a very thin, breathable film that doesn't feel greasy or sticky on skin or hair.
Water resistance
It helps sunscreen and makeup stay effective longer when you sweat or go swimming, reducing the need for frequent reapplication.
Cons and cautions
Synthetic origin
It is a lab-made silicone derivative, which may be a turn-off for those who prefer naturally derived ingredients in their routine.
Potential buildup
On hair, repeated use without a clarifying wash can lead to a slight buildup over time, making hair feel less bouncy.
Best for
- People looking for a lightweight, non-greasy conditioner or styling aid
- Those who want water-resistant sunscreens or long-wear makeup
Use caution if
- Individuals strictly avoiding all silicones or synthetic polymers
Usage tips
Safety summary
Bis-Isobutyl PEG-15/Amodimethicone Copolymer is considered safe for use in cosmetics at typical concentrations. It has low irritation and comedogenic potential. The Cosmetic Ingredient Review (CIR) panel has reviewed similar amodimethicone copolymers and found them safe as used.
Research notes
Evidence comes primarily from safety assessments by cosmetic ingredient panels and formulation studies. No large-scale human clinical trials exist, but the ingredient's structure is well understood and its safety profile is supported by analogy to related silicones.
Common label clues
- Typical concentration
- 0.5% to 5%
- Regulatory status
- Approved for use in cosmetics in the US (FDA), EU (CosIng), and other major markets. No concentration restrictions are specified for this specific copolymer.
- Common uses
- Hair conditioners, Leave-in treatments, Styling products, Water-resistant sunscreens, Color cosmetics
- Environmental note
- As a silicone-based polymer, it may not biodegrade quickly. However, its large molecular size reduces absorption into aquatic organisms. Research on environmental fate is ongoing.
Good to know
- This ingredient is often found in 'long-wear' or 'water-resistant' formulas.
- It is considered safe by major cosmetic safety panels at typical use levels.
Common questions
What is Bis-Isobutyl PEG-15/Amodimethicone Copolymer in beauty products?
This is a man-made silicone ingredient that forms a thin, flexible film on your skin or hair. It helps lotions and creams glide on easily, makes hair feel silky and less frizzy, and can help makeup or sunscreen stay put longer, even in water. Think of it as a lightweight, breathable coating that doesn't feel heavy or greasy.
What does Bis-Isobutyl PEG-15/Amodimethicone Copolymer do in a beauty product?
When applied, the copolymer spreads into an even, ultra-thin layer that adheres to skin or hair. The amodimethicone part provides slip and conditioning, while the PEG section allows water to pass through, so the film doesn't trap moisture or feel sticky. This helps products feel lightweight and resist washing off from sweat or water.
Is Bis-Isobutyl PEG-15/Amodimethicone Copolymer safe for most people?
Bis-Isobutyl PEG-15/Amodimethicone Copolymer is considered safe for use in cosmetics at typical concentrations. It has low irritation and comedogenic potential. The Cosmetic Ingredient Review (CIR) panel has reviewed similar amodimethicone copolymers and found them safe as used.
Who should be careful with Bis-Isobutyl PEG-15/Amodimethicone Copolymer?
Individuals strictly avoiding all silicones or synthetic polymers
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.