Is a dog dressed as a bumble bee a dog or a bumble bee?

It is still a dog. Likewise, formaldehyde dressed up as DMDM Hydantoin is still formaldehyde!

What is DMDM Hydantoin? It is an antimicrobial formaldehyde releasing preservative.

What is listed on the bottle: DMDM Hydantoin or DMDH Hydantoin.

A little history lesson: When formaldehyde went out of popularity as a preservative because of its strong links to cancer, a "slow releasing" formaldehyde was developed. This "new formaldehyde" slowly releases small amounts of formaldehyde over time instead of having straight formaldehyde in the product's formulation. 

Why should I be concerned? In the US, there are no restrictions on the levels of formaldehyde allowed in pet grooming products and there are no requirements to test products made with formaldehyde-releasing preservatives for levels of formaldehyde. There are also no obligations for manufacturers to tell customers that the pet grooming products they are using contain an ingredient that has links to cancer, and strong links to allergies and skin irritation. 

In addition, a product that contains slow-releasing formaldehyde increases in the level it contains the longer it sits.  So when a product first rolls off the production line it is less potent in terms of formaldehyde levels than it is after it sits on a shelf in a store, and then under the cabinet when it's purchased and brought home.  Since very few pet grooming products come stamped with a "use by" date, as a consumer you have no way of knowing how much formaldehyde has been slowly released in it since production.  YIKES! 

Manufacturers who use DMDM Hydantoin will tell you they are used at low levels and pose less of a risk than formaldehyde. Well, ok. ANY amount of formaldehyde is TOO MUCH formaldehyde in our opinion!