Alright, I guess I need to do a thread on DMDM hydantoin so here we go...

What is it? A preservative. Why the sudden controversy? There's a lawsuit - two people are claiming they got "scalp burns" and hair loss after using a TRESemmé shampoo and filed a lawsuit claiming that this was due to the use of DMDM hydantoin in the product.

BEFORE I PROCEED: All I have to go on is information that's publicly available. I haven't treated anyone in the lawsuit and I'm sure we'll learn more as time progresses. I'm just speculating.

The lawsuit cites that DMDM hydantoin releases "carcinogenic formaldehyde" and that this was the reason for the findings. Firstly, the amount of formaldehyde released by this compound is negligible. Second, whether or not it's a carcinogen would have no bearing on hair loss.

It sounds like these two people had some sort of inflammatory reaction. Could it be due to the product? Sure. I think the easiest explanation is a contact allergy to something in the formula. DMDM hydantoin could potentially be the culprit then.

My question though: why wouldn't we then put the entire formula under the microscope then? The product also includes methyloisothiazolinone and methychloroisothiazolinone which are known to cause sometimes very exuberant contact dermatitis.

These two preservatives rose to prominence (surprise surprise) after parabens became demonized and have resulted in rampant contact dermatitis.

Regardless, if this is the case, these people were allergic to something in the formula. That doesn't mean everyone has to avoid it. That said, I'm sure we will all learn more as time goes on. If your hair products aren't giving you any issues, don't throw them out.

The danger here is that creators (even some physicians) are taking a tiny piece of the story and extrapolating it out in order to fear monger and gain views. THAT'S NOT OK!

Boiling this issue down to "this chemical will make your hair fall out" is factually inaccurate.