Ingredient review

Polyoxymethylene Cyanoguanidine Urea

INCI: POLYOXYMETHYLENE CYANOGUANIDINE UREA

A synthetic film-former that helps products stay put, but it's rarely used in modern skincare and has limited research on long-term skin effects.

beautyskincarefilm-former

In plain English

This is a man-made polymer that creates a thin, flexible film on skin, hair, or nails. Think of it like a clear, invisible coating that helps makeup or hair products last longer. It's not a moisturizer or active ingredient—it's more of a helper ingredient that improves texture and wear. Because it's not very common in everyday skincare, you'll mostly find it in specialty products like long-wear mascara or strong-hold hair gels.

Review score

Safety, usefulness, and evidence

3.0Fair
3.0/ 5

Useful in the right context, but not low-maintenance

The evidence base is still emerging, so marketing claims deserve extra caution.

Risk flags are low for most users, though the finished product can still irritate.

Source
synthetic
Evidence
emerging
Irritation
low
Clogging risk
low
How reviews are scored

Quick decision guide

Read the cautions before using

Polyoxymethylene Cyanoguanidine Urea 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.

  1. Step 1Start with the score, then check the irritation and clogging risk before judging Polyoxymethylene Cyanoguanidine Urea.
  2. Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
  3. 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

low

Less likely to sting, burn, or bother most users, though sensitive skin can still react.

Clogging risk

low

Less likely to feel heavy or contribute to clogged pores for most skin types.

Evidence level

emerging

The ingredient may be promising, but claims should be treated more cautiously.

What it is

A synthetic polymer formed by reacting urea, cyanoguanidine, and formaldehyde (as polyoxymethylene). It belongs to a class of ingredients called amino resins, which are used for their film-forming and thickening properties.

How it works

When applied, the polymer molecules link together to form a continuous film on the surface of the skin, hair, or nails. This film helps other ingredients stay in place, reduces water loss from the surface, and can give a smooth, even appearance. It also increases the viscosity (thickness) of a product, making it easier to apply precisely.

Pros

Improves product longevity

The film it forms helps makeup and hair products resist smudging, fading, or running, so you get longer wear without touch-ups.

Enhances application texture

By thickening the formula, it makes products like mascara or gel easier to apply smoothly and evenly, reducing clumps or drips.

Cons and cautions

Potential formaldehyde concern

During manufacturing, trace amounts of formaldehyde can be released. While finished products are regulated to keep levels safe, some people prefer to avoid any potential exposure.

Limited skin research

There are few modern studies on how this polymer interacts with skin over time, so its long-term effects are not well understood compared to more common film-formers.

Best for

  • People looking for long-wearing mascara or eyeliner
  • Those who want strong-hold hair styling products

Use caution if

  • Individuals with known sensitivity to formaldehyde-releasing ingredients

Usage tips

Check the full ingredient list if you have a known formaldehyde allergy, as this ingredient may be associated with trace formaldehyde.
Use in conjunction with moisturizers if you have dry skin, as the film can sometimes feel tight or drying on its own.

Safety summary

Generally recognized as safe for topical use in low concentrations. The main concern is potential trace formaldehyde, which is tightly regulated. For most people, occasional use in rinse-off or leave-on products poses minimal risk.

Research notes

Very limited peer-reviewed research on this specific ingredient in cosmetic contexts. Most safety data comes from industry assessments and regulatory reviews rather than independent clinical studies.

Common label clues

Typical concentration
Typically used at 0.5–5% in leave-on products
Regulatory status
Approved for use in cosmetics in the US (FDA) and EU (CosIng) with concentration limits on free formaldehyde. Always used at levels considered safe by industry panels.
Common uses
Nail care, Hair styling products, Mascara
Environmental note
As a synthetic polymer, it may not be biodegradable. Its environmental impact is not well studied, but it is not known to be a major pollutant.

Good to know

  • This ingredient is not commonly found in everyday moisturizers or serums—it's more typical in specialty cosmetics like long-wear makeup and hair gels.
  • The name 'polyoxymethylene' refers to a polymer form of formaldehyde, but the final ingredient is a complex resin, not free formaldehyde.

Common questions

What is Polyoxymethylene Cyanoguanidine Urea in beauty products?

This is a man-made polymer that creates a thin, flexible film on skin, hair, or nails. Think of it like a clear, invisible coating that helps makeup or hair products last longer. It's not a moisturizer or active ingredient—it's more of a helper ingredient that improves texture and wear. Because it's not very common in everyday skincare, you'll mostly find it in specialty products like long-wear mascara or strong-hold hair gels.

What does Polyoxymethylene Cyanoguanidine Urea do in a beauty product?

When applied, the polymer molecules link together to form a continuous film on the surface of the skin, hair, or nails. This film helps other ingredients stay in place, reduces water loss from the surface, and can give a smooth, even appearance. It also increases the viscosity (thickness) of a product, making it easier to apply precisely.

Is Polyoxymethylene Cyanoguanidine Urea safe for most people?

Generally recognized as safe for topical use in low concentrations. The main concern is potential trace formaldehyde, which is tightly regulated. For most people, occasional use in rinse-off or leave-on products poses minimal risk.

Who should be careful with Polyoxymethylene Cyanoguanidine Urea?

Individuals with known sensitivity to formaldehyde-releasing ingredients

Research sources

CosIng - European Commission databaseOpenFDA Cosmetics Ingredient DirectoryOpenCIR Safety Assessment of Amino ResinsOpen

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.