What Is Imidazolidinyl Urea?
Imidazolidinyl Urea is a synthetic preservative made from a combination of urea and formaldehyde that has been reacted and processed to create a stable compound.
First introduced in the 1970s as an alternative to older, harsher preservatives, it helped cosmetic makers keep creams and lotions free of harmful microbes for longer periods. During production, chemists mix urea with formaldehyde under controlled heat and pH conditions, then purify the result to remove leftover raw materials. The finished ingredient appears as a white, odorless powder that dissolves well in water-based formulas.
You will commonly find it in moisturizers, face masks, cleansers, liquid foundations, antiperspirants and hair conditioners where long shelf life is important.
Imidazolidinyl Urea’s Cosmetic Benefits/Uses
This ingredient serves one main purpose in beauty products.
As a preservative, Imidazolidinyl Urea controls the growth of bacteria, yeast and mold in water rich formulas which helps keep products safe to use over time without refrigeration.
Who Can Use Imidazolidinyl Urea
Most skin types tolerate Imidazolidinyl Urea well. It is generally suitable for oily, combination and normal skin because it sits in the formula rather than on the skin itself and does not clog pores. Dry or sensitive skin can usually handle it too, though people with a known formaldehyde allergy or chronic conditions like eczema may experience irritation and should be more cautious.
The ingredient is produced synthetically without animal by-products so it is considered appropriate for both vegans and vegetarians.
Current safety assessments find Imidazolidinyl Urea acceptable for use during pregnancy and breastfeeding at the low levels found in cosmetics. This is not medical advice and anyone who is pregnant or nursing should discuss all skincare choices with a qualified healthcare provider.
Imidazolidinyl Urea does not increase photosensitivity, so it will not make skin more prone to sunburn. No special storage or handling precautions are needed beyond keeping the product tightly closed and away from extreme heat.
Potential Side Effects/Adverse Reactions
Side effects and reactions to topical Imidazolidinyl Urea vary from person to person. The points below show potential issues that could occur, but most users will not experience them when the ingredient is used at approved levels in well-formulated products.
- Skin irritation such as redness, itching or burning
- Contact dermatitis in individuals sensitive to formaldehyde releasers
- Eye stinging if the product accidentally gets into the eyes
- Worsening of pre-existing eczema in susceptible users
If any of these effects appear, stop using the product and seek advice from a healthcare professional.
Comedogenic Rating
Rating: 0/5
Imidazolidinyl Urea is water soluble and used in very small amounts, usually below 1%. It does not create an oily film, does not linger on the skin surface and is quickly diluted by the rest of the formula. Because of these factors it has virtually no ability to block pores, earning a solid zero on the comedogenic scale.
That makes it appropriate for people who are prone to acne or breakouts.
While it will not clog pores, remember it is a formaldehyde-releasing preservative, so anyone with a known sensitivity to that class of ingredients should still read labels carefully.
Summary
Imidazolidinyl Urea is a synthetic preservative whose main job is to keep water-based cosmetics free from bacteria, yeast and mold. It does this by slowly releasing tiny amounts of formaldehyde that disrupt microbial cell walls so products stay safe and usable for longer.
The ingredient enjoyed wide popularity starting in the 1970s and is still common today in lotions, creams and makeup, though some brands are swapping it out in favor of newer preservative blends to satisfy consumers looking for formaldehyde-free labels.
At the concentrations allowed in cosmetics it is considered safe by regulatory bodies around the world with only a small percentage of users experiencing irritation. As with any skin care ingredient it is smart to perform a quick patch test when trying a new product that contains Imidazolidinyl Urea just to be safe.