Try to say those three times fast.
Are these chemicals as bad as they sound like they might be?
According to this site (and tons of others--even unbiased sites that aren't trying to sell something), both of these chemicals are preservatives. They are also known to be strong allergens.
Additionally, they're becoming something I'm seeing more and more of on product labels, especially since the paraben-free craze began a couple years ago.
Methylchloroisothiazolinone and Methylisothiazolinone are alternatives to parabens, which are also preservatives. I assume companies started using them because the word "paraben" was becoming so recognizable as a detrimental ingredient. As people started avoiding products with parabens, my guess is companies started developing products with Methylchloroisothiazolinone and Methylisothiazolinone as unrecognizable alternatives so they could stamp "paraben free" on their labels and win back health-conscious consumers.
The chemical structure of Methylchloroisothiazolinone
Let's head on over to the Environmental Working Group's Skin Deep Cosmetic Safety Database to get a little more information...
Here are the scores for the parabens:
Methylparaben = 5
Butylparaben = 6
Propylparaben = 6
Remember, on this scale of 0-10 a 10 is the worst. These chemicals are in the mid-to-high range, which, I guess, might not seem bad to some people, but these are often used in combination. More than one of them will show up on one product's ingredients list. So yeah... that concerns me and those who think like I do.
But this entry isn't about parabens, so let me move on.
Here are the scores for these hard-to-pronounce alternatives:
Methylchloroisothiazolinone = 6
Methylisothiazolinone = 6
Guess what! These two aren't just allergens. Methylchloroisothiazolinone is also linked to cancer, immune system toxicity, and asthma. Methylisothiazolinone has ties to immune system toxicity and neurotoxicity.
Yes, the parabens, if you look them up, are just as bad--maybe worse (they also are linked to developmental/reproductive toxicity, organ system toxicity, and endocrine disruption)--but in my mind they're near enough to comparable. Usually I'll be the first to say "some change is good change", but in this case I don't think that's true and I intend to go out of my way to avoid them as much as I do to avoid parabens.
Methylchloroisothiazolinone and Methylisothiazolinone are definitely on my no-no list.
(This article was originally posted on my old blog, Glamoursaurus Goes Natural, which is now defunct.)