Ingredient review
Poloxamer 338 / PPG-51 SMDI Copolymer
INCI: POLOXAMER 338/PPG-51/SMDI COPOLYMER
A synthetic film-former that helps products stay put and feel smooth, but offers no direct skin benefit.
In plain English
This ingredient is a synthetic polymer that creates a thin, flexible film on your skin. Think of it like a very lightweight, invisible layer that helps other ingredients (like sunscreen or foundation) stay in place longer and resist water or sweat. It doesn't actively treat or moisturize your skin, but it improves how a product feels and performs.
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
Poloxamer 338 / PPG-51 SMDI 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 Poloxamer 338 / PPG-51 SMDI 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 large molecule made by combining poloxamer (a type of surfactant) with a modified polyurethane. It is designed to form a smooth, even film on the skin.
How it works
When applied, the polymer molecules link together as the water or solvent evaporates, forming a continuous, flexible film. This film helps lock in other ingredients, reduces transfer (for makeup), and can improve water resistance (for sunscreen).
Pros
Boosts product longevity
Helps sunscreen and makeup resist sweat, water, and rubbing, so you don't have to reapply as often.
Improves sensory feel
Leaves a smooth, silky finish on the skin without a greasy or sticky residue.
Cons and cautions
No skin benefit
This ingredient is purely functional—it doesn't hydrate, soothe, or repair the skin.
Synthetic and not eco-friendly
As a synthetic polymer, it is not biodegradable and may raise environmental concerns for some users.
Best for
- Anyone wanting longer-lasting makeup or sunscreen
- People with oily or combination skin who prefer a matte finish
Use caution if
- Those who prefer only naturally-derived ingredients
- Individuals with very dry or dehydrated skin who may find film-formers uncomfortable
Usage tips
Safety summary
Poloxamer 338/PPG-51/SMDI Copolymer is considered safe for topical use at typical cosmetic concentrations. It has a low irritation and comedogenic risk. However, as a synthetic polymer, it offers no skin benefit and is not biodegradable.
Research notes
There is limited peer-reviewed research specifically on this copolymer. Its safety is inferred from related poloxamer and polyurethane compounds, which have a long history of safe use in cosmetics. Most evidence comes from manufacturer safety data sheets and regulatory reviews.
Common label clues
- Typical concentration
- 0.5% to 5%
- Regulatory status
- Approved for use in cosmetics in the EU, USA, and other major markets. No specific concentration restrictions beyond general cosmetic safety guidelines.
- Common uses
- Sunscreens, Long-wear foundations, Water-resistant formulas
- Environmental note
- As a synthetic polymer, it is not readily biodegradable. Some manufacturers are working on bio-based alternatives, but this version is petroleum-derived.
Good to know
- This ingredient is often part of a complex blend and may appear under alternative INCI names like 'Polyurethane-XX'.
- It is considered safe for use in cosmetics by major regulatory bodies at typical concentrations.
Common questions
What is Poloxamer 338 / PPG-51 SMDI Copolymer in beauty products?
This ingredient is a synthetic polymer that creates a thin, flexible film on your skin. Think of it like a very lightweight, invisible layer that helps other ingredients (like sunscreen or foundation) stay in place longer and resist water or sweat. It doesn't actively treat or moisturize your skin, but it improves how a product feels and performs.
What does Poloxamer 338 / PPG-51 SMDI Copolymer do in a beauty product?
When applied, the polymer molecules link together as the water or solvent evaporates, forming a continuous, flexible film. This film helps lock in other ingredients, reduces transfer (for makeup), and can improve water resistance (for sunscreen).
Is Poloxamer 338 / PPG-51 SMDI Copolymer safe for most people?
Poloxamer 338/PPG-51/SMDI Copolymer is considered safe for topical use at typical cosmetic concentrations. It has a low irritation and comedogenic risk. However, as a synthetic polymer, it offers no skin benefit and is not biodegradable.
Who should be careful with Poloxamer 338 / PPG-51 SMDI Copolymer?
Those who prefer only naturally-derived ingredients Individuals with very dry or dehydrated skin who may find film-formers uncomfortable
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.