Ingredient review
PEI-1400
INCI: PEI-1400
PEI-1400 is a synthetic polymer that helps products stay put, but it's not a skincare active and may feel heavy on some skin types.
In plain English
PEI-1400 is a man-made ingredient that forms a thin, flexible film on skin or hair. It's used to help makeup last longer, keep hair in place, or bind ingredients together. Think of it like a gentle glue that holds a product's texture and performance together. It's not a moisturizer or treatment ingredient, so it won't hydrate or repair skin.
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
PEI-1400 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 PEI-1400.
- 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
PEI-1400 is a synthetic polymer derived from ethyleneimine monomers. It is a water-soluble, cationic (positively charged) polymer that forms films and binds ingredients.
How it works
When applied, PEI-1400 dries to form a clear, flexible film on the skin or hair surface. This film helps lock in other ingredients, improves water resistance, and gives a smooth, even finish. Its positive charge also helps it adhere to negatively charged surfaces like hair and skin.
Pros
Long-lasting wear
PEI-1400 helps makeup and hair products resist smudging, fading, and humidity, so your look stays fresh longer.
Smooth finish
It forms an even film that can give skin or hair a polished, uniform appearance without visible flakes or clumps.
Cons and cautions
Not a treatment ingredient
PEI-1400 is a functional polymer, not a moisturizer or active. It won't hydrate, soothe, or repair skin.
Potential heaviness
On oily or combination skin, the film can feel sticky or heavy, especially in high-humidity conditions.
Best for
- People who want long-lasting makeup or hair hold
- Those with normal to dry skin looking for a smooth finish
Use caution if
- People with very oily or acne-prone skin who may find film-formers heavy
- Those seeking purely hydrating or active skincare ingredients
Usage tips
Safety summary
PEI-1400 is considered safe for cosmetic use at typical concentrations. It has low irritation and comedogenic potential, but high concentrations may cause dryness or tackiness. No serious safety concerns have been reported in peer-reviewed literature.
Research notes
Research on PEI-1400 in cosmetics is limited. Most safety data come from general polymer toxicology and industry assessments. It is not a well-studied active ingredient, but its film-forming properties are well understood.
Common label clues
- Typical concentration
- Typically used at 0.1–2% in leave-on products, up to 5% in rinse-off products
- Regulatory status
- Approved for use in cosmetics in the US (FDA) and EU (CosIng) with no specific restrictions at typical concentrations.
- Common uses
- Mascaras, Eyeliners, Hair styling products, Setting sprays
- Environmental note
- As a synthetic polymer, PEI-1400 is not biodegradable and may persist in the environment. Some brands are moving toward biodegradable alternatives.
Good to know
- PEI-1400 is often used in 'waterproof' or 'long-wear' formulas.
- It is not a common ingredient in simple moisturizers or serums—look for it in makeup and styling products.
Common questions
What is PEI-1400 in beauty products?
PEI-1400 is a man-made ingredient that forms a thin, flexible film on skin or hair. It's used to help makeup last longer, keep hair in place, or bind ingredients together. Think of it like a gentle glue that holds a product's texture and performance together. It's not a moisturizer or treatment ingredient, so it won't hydrate or repair skin.
What does PEI-1400 do in a beauty product?
When applied, PEI-1400 dries to form a clear, flexible film on the skin or hair surface. This film helps lock in other ingredients, improves water resistance, and gives a smooth, even finish. Its positive charge also helps it adhere to negatively charged surfaces like hair and skin.
Is PEI-1400 safe for most people?
PEI-1400 is considered safe for cosmetic use at typical concentrations. It has low irritation and comedogenic potential, but high concentrations may cause dryness or tackiness. No serious safety concerns have been reported in peer-reviewed literature.
Who should be careful with PEI-1400?
People with very oily or acne-prone skin who may find film-formers heavy Those seeking purely hydrating or active skincare 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.