The following info was compiled for Kim Raisanen of the Professional Cat Groomers Association of America. I trust it will be valuable to others who are interested in the ingredients used in pet grooming products.
USAGE: BROAD SPECTRUM PRESERVATIVE (Alternative to Parabens)
PRESERVATIVE TYPE: FORMALDEHYDE DONOR (along with quaternium-15, imidazolidinyl urea, diazolidinyl urea, sodium hydroxymethylglycinate, 2-bromo-2-nitropropane-1,3-diol (bromopol)
- DMDM Hydantoin is used in cosmetic products at concentrations up to 1%. 1 Most commonly it is used at concentrations of 0.2-0.6%. That’s 2/10ths to 6/10ths of one percent.
- DMDM Hydantoin releases less formaldehyde than found in foods.2
- Formaldehyde that is released in water-based solutions, such as shampoos, will immediately mix with water in the product and instantly convert into methylene glycol, so there’s virtually no chance of inhaling harmful levels of formaldehyde gas.2
- The safety of DMDM Hydantoin has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The CIR Expert Panel evaluated the scientific data and concluded that DMDM Hydantoin was safe as a cosmetic ingredient in the present practices of use. In 2005, the CIR Expert Panel considered available new data on DMDM Hydantoin and reaffirmed the above conclusion. It is approved universally in Japan, USA and Europe.1
- DMDM Hydantoin has low oral toxicity and is not carcinogenic.
- It has shown occasional dermal irritation, but does not appear to be cause sensitizer (does not cause allergic response) in animal testing1. In human dermatological studies it has shown up as a sensitizer, especially in those individuals with known allergy to formaldehyde. 3
The concerns over the safety of DMDM Hydantoin and other preservatives that are formaldehyde releasers seems mostly based on the fear of formaldehyde. Full strength Formaldehyde gas is extremely toxic and is a known carcinogen. Formaldehyde occurs naturally in many foods, especially fruits & vegetables.4 The amount of formaldehyde released in cosmetics preservatives is less than that found naturally occurring in foods. Moreover, some scientists claim that any formaldehyde that is released in a solution containing water is immediately converted to another substance, methylene glycol. They maintain that actually NO FORMALDEHYDE can exist in shampoos and conditioners. Concern over DMDM Hydantoin would be most appropriate in regards to creams, not hair products.
DMDM Hydantoin has a very low oral toxicity, making it quite safe for cats. It does not cause cancer. It has been determined to be a sensitizer for some humans (causes allergic reaction), but this was not established in animal studies. In studies of albino rabbits, it showed minimal transient irritation. 5
CONCLUSION: DMDM Hydantoin has been thoroughly studied, reviewed and re-reviewed by the CIR Expert Panel, and determined to be safe as used in cosmetics. It is considered an acceptable alternative to parabens, with a slightly greater potential for skin irritation or allergic reaction. This would not likely exhibit in a diluted, rinse-off, water-based shampoo for pets.
LOOK for our article on preservatives in the forthcoming issue of eGroomer Journal, Jan. 2014.
1.CIR Final Report on the Safety Assessment of DMDM Hydantoin: Abstract
2. Exposing the Formaldehyde Myth, Doug Schoon, Personal Care Truth or Scare, August 11, 2010. http://personalcaretruth.com/2010/08/exposing-the-formaldehyde-myth/
3. National Library of Medicine HSDB Database – 1,3-Dimethylol-5,5-Dimethyhydantoin. http://toxnet.nlm.nih.gov/cgi-bin/sis/search/a?dbs+hsdb:@term+@DOCNO+7488