Ingredient review
PEI-700
INCI: PEI-700
PEI-700 is a synthetic film-former that helps products stay put, but it has limited safety data and can be irritating for sensitive skin.
In plain English
PEI-700 is a man-made ingredient that creates a thin, flexible film on your skin or hair. Think of it like a clear, invisible coating that helps makeup last longer or helps hair hold its shape. It's often found in products that need to be water-resistant or long-wearing, like mascara and eyeliners. Because it's a polymer, it can feel a bit tight or stiff on the skin, and some people find it irritating.
Review score
Safety, usefulness, and evidence
Useful in the right context, but not low-maintenance
The evidence base is still emerging, so marketing claims deserve extra caution.
Main practical flags: irritation is moderate; clogging risk is low.
- Source
- synthetic
- Evidence
- emerging
- Irritation
- moderate
- Clogging risk
- low
Quick decision guide
Read the cautions before using
PEI-700 can be useful, but watch for some irritation potential.
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-700.
- 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
moderateCan bother some users, especially with frequent use, damaged skin, or strong companion ingredients.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
emergingThe ingredient may be promising, but claims should be treated more cautiously.
What it is
PEI-700 is a synthetic polymer, specifically a polyethyleneimine with an average molecular weight of 700. It is produced through chemical synthesis and is used in cosmetics for its film-forming and binding properties.
How it works
When applied, PEI-700 forms a continuous, flexible film on the surface of the skin, hair, or nails. This film helps other ingredients adhere better, improves water resistance, and can create a smooth, even appearance. It also acts as a binder, helping to hold pressed powders or pigments together.
Pros
Long-lasting wear
PEI-700 helps makeup and sunscreens stay put for hours, even in humid or wet conditions, so you don't have to reapply as often.
Improves texture
It creates a smooth, even film that can make skin and hair feel silky and look more polished, especially in eyeliners and mascaras.
Cons and cautions
Potential irritation
PEI-700 can be irritating for sensitive skin, causing redness, itching, or a tight feeling. It's best to patch test before widespread use.
Limited safety data
There is not a lot of published research on the long-term safety of PEI-700 in cosmetics, so its full risk profile is not well understood.
Best for
- People looking for long-wearing, water-resistant makeup
- Those who want a smooth, film-forming finish in hair styling products
Use caution if
- Individuals with sensitive or reactive skin
- Those who prefer natural or biodegradable ingredients
Usage tips
Safety summary
PEI-700 is considered safe for use in cosmetics at low concentrations, but it can cause skin irritation in some individuals. Long-term safety data is limited, so it's best used with caution, especially for those with sensitive skin.
Research notes
Research on PEI-700 in cosmetics is sparse. Most available data comes from industrial or biomedical contexts, where it is used as a gene delivery agent. Its safety profile in topical cosmetic use is not well-established.
Common label clues
- Typical concentration
- Typically used at low concentrations, often under 2%
- Regulatory status
- PEI-700 is not specifically restricted by the FDA for cosmetic use, but it is not widely reviewed by safety panels like the Cosmetic Ingredient Review (CIR). It is allowed in cosmetics in the EU under general safety requirements.
- Common uses
- Mascara, Eyeliners, Hair styling products, Water-resistant sunscreens
- Environmental note
- PEI-700 is a synthetic polymer that is not readily biodegradable. Its persistence in the environment is a concern, and it may accumulate in waterways.
Good to know
- PEI-700 is not the same as polyethylene glycol (PEG), though both are synthetic polymers.
- It is sometimes used in industrial applications, which is why cosmetic-grade purity is important.
- The '700' refers to its average molecular weight, which affects how it behaves in formulas.
Common questions
What is PEI-700 in beauty products?
PEI-700 is a man-made ingredient that creates a thin, flexible film on your skin or hair. Think of it like a clear, invisible coating that helps makeup last longer or helps hair hold its shape. It's often found in products that need to be water-resistant or long-wearing, like mascara and eyeliners. Because it's a polymer, it can feel a bit tight or stiff on the skin, and some people find it irritating.
What does PEI-700 do in a beauty product?
When applied, PEI-700 forms a continuous, flexible film on the surface of the skin, hair, or nails. This film helps other ingredients adhere better, improves water resistance, and can create a smooth, even appearance. It also acts as a binder, helping to hold pressed powders or pigments together.
Is PEI-700 safe for most people?
PEI-700 is considered safe for use in cosmetics at low concentrations, but it can cause skin irritation in some individuals. Long-term safety data is limited, so it's best used with caution, especially for those with sensitive skin.
Who should be careful with PEI-700?
Individuals with sensitive or reactive skin Those who prefer natural or biodegradable 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.