Imidazolidinyl Urea
ih-MID-ah-zol-ID-in-ul yoo-REE-ah
What Is Imidazolidinyl Urea?
A synthetic preservative that works by releasing small amounts of formaldehyde to prevent microbial growth. It is one of the most common formaldehyde-releasing preservatives in cosmetics.
Source: Synthetic compound
Origin: Synthetic
Also known as: Germall 115
What Does Imidazolidinyl Urea Do to Your Hair?
Releases formaldehyde slowly to provide broad-spectrum antimicrobial preservation. Effective against bacteria but less effective against fungi, so it is often combined with parabens or other preservatives.
Best For
None recommended
Not Recommended For
Sensitive scalp, formaldehyde-sensitive individuals, all hair types seeking clean ingredients
Concentration Matters
0.1-0.6% in products
Hair Type Compatibility
Method Compatibility
Safety & Regulation
A formaldehyde-releasing preservative. Formaldehyde is a known human carcinogen at high exposures. While cosmetic concentrations are low, many consumers and experts prefer to avoid formaldehyde releasers entirely.
FDA Status: Generally Recognized As Safe
FDA permits use in cosmetics but formaldehyde is classified as a known carcinogen by IARC. EU restricts free formaldehyde to 0.2% in cosmetics.
EWG Score: 6/10
HairAide Verdict
A formaldehyde-releasing preservative that many consumers rightly choose to avoid. While concentrations are low, safer preservative alternatives are widely available. Check ingredient lists if you want to steer clear.
Products That Contain Imidazolidinyl Urea
Shampoos, conditioners (being phased out by many brands)
Alternatives to Imidazolidinyl Urea
If you want to avoid Imidazolidinyl Urea, look for products with these ingredients instead:
Phenoxyethanol, Benzyl Alcohol, Sodium Benzoate, Potassium Sorbate
Frequently Asked Questions
Imidazolidinyl Urea has a safety rating of 3/10 and may be problematic for many hair types. A formaldehyde-releasing preservative. Formaldehyde is a known human carcinogen at high exposures. While cosmetic concentrations are low, many consumers and experts prefer to avoid formaldehyde releasers entirely.
Imidazolidinyl Urea is not CG-method approved. Curly hair types may want to avoid this ingredient or use products containing it sparingly.
No, Imidazolidinyl Urea is not approved for the Curly Girl method.
Some alternatives to Imidazolidinyl Urea include: Phenoxyethanol, Benzyl Alcohol, Sodium Benzoate, Potassium Sorbate
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