That goes particularly for a chemical frequently used in many cosmetics and personal care products:
Methylchloroisothiazolinone (MCI).
You may have noticed it on a product label. Your eyes may have tripped over it.
Although it isn't the most blatantly harmful ingredient in modern cosmetic and personal care products, it's still one to avoid.
The General Problem
Although Beauty is a $532 billion industry in the United States, cosmetics are the least regulated.
That doesn't mean any and every beauty or skincare product could immediately poison you. The manufacturers use ingredients we know are safe in the short run.
In the long run, we're all . . . anyway, right?
But we want to delay that, not speed the process up.
Therefore, although the government does test ingredients for short-term risk, there's no way they can be completely sure how, in the long run, our bodies will react to the various chemicals used.
Or, especially, in combination with other chemicals.
The average American woman uses twelve personal care products every day.
And, remember, although your skin is a physical barrier, it's permeable. That is, molecules that are small enough do go down into and through your skin - some are designed to go quite deep.
You can even say your skin "eats" the chemicals in the products you apply onto your skin.
Unfortunately, your skin doesn't have stomach acid or a liver to protect you.
When you eat something harmful, your stomach acid and digestive fluids work hard to protect you from harmful effects.
If something's dangerous, it's your liver's job to detoxify it and remove it from your body.
Your skin has no such guardians or filters. What you apply to your skin, stays in it.
Personal care and cosmetic companies purposely design their products to act on your skin as quickly as possible.
This is roughly equivalent to how commercial food manufacturers design their products to powerfully appeal to your cravings for salt, fat and sugar.
Yes - commercial cosmetics are to your skin what fast food is to your digestion.
The European Union has banned 1,300 chemicals that are still allowed in the United States.
Five Potential Health Hazards from Cosmetic/Personal Care Product Ingredients
1. Direct carcinogens
2. Hidden carcinogens
3. Endocrine disruptors
4. Allergens
5. Penetrators - these drive other product ingredients down deeper into your skin
Common Ingredients to Beware:
1. Parabens
2. Hydroquinone
3. Phthalates
4. Formaldehyde
5. Triclosan (has been banned from hand soap, but is still allowed in personal care products)
6. Polyethylene glycol (PEG)
7. Methylchloroisothiazolinone (MCI)
About Methylchloroisothiazolinone
MCI is used in water-based cosmetics and other personal care products as a preservative. It does protect products against yeast, bacteria and fungi contamination. It's commonly used along with methylisothiazolinone (MIT).
They both inhibit the growth of bacteria, but do so more effectively together - trade name: Kathon CG.
They inhibit the growth of most anerobic and aerobic bacteria.
Besides personal care products, MCI (often along with MIT) is also used for industrial applications: detergents, glue, fuels and paints.
Examples of How They Look on Product Labels
* Methylisothiazolinone (MCI): 2-methyl-4-isothiazoline-3-one, Neolone 950 preservative, MI, OriStar MIT and Microcare MT.
* Methylchloroisothiazolinone (CMIT): 5-Chloro-2-methyl-4-isothiazolin-3-one and MCI.
* UNII-15O9QS218W COMPONENT DHNRXBZYEKSXIM-UHFFFAOYSA-N
* Q204121
* Q-9256
* 5-CHLORO-2-METHYL-4-ISOTHIAZOLIN-3-ONE
* X5928
* 5-CHLORO-2-METHYL-2,3-DIHYDRO-1,2-THIAZOL-3-ONE
* DB-007017
* SR-01000944864
* W-107193
* SR-01000944864-1
Once you know about it, it sticks right out, doesn't it?
Well, obviously, it's not clear - and that's all the more reason you need to know what to look for, and to always pay attention to what you're buying.
Health Risks of MCI and Its Related History
Cosmetic and personal care manufacturers began using it in the 1970's.
In 1988, medical researchers figured out MCI is a contact allergen. That is, it causes allergic reactions in many people.
In high concentrations, MCI irritates both skin and membranes, causing chemical burns.
Some people experience worsening of MCI-caused skin lesions after exposure to sunlight.
In 2013, the American Contact Dermatitis Society made MIT Allergen of the Year.
In the United States now, MCI is not allowed in products that you apply to your skin and leave on. It may only be used in "rinse-off" products, such as shampoo, where its contact with skin is only temporary.
However, in the US MCI may be allowed in a stay-on product if it's been formulated to be nonallergenic.
In the European Union, MCI and MIT are allowed only in rinse-off products.
However, you must still exercise caution. There are noncompliant products in the marketplace.
MCI and MIT are two of the most common contact allergens found cosmetic products. They are most irritating when used together.
Other Health Concerns
Rats exposed to a high concentration exhibited frightening symptoms. These ranged from sudden weight gain to death with reddened lungs and swollen intestines.
When scientists exposed cerebral cortex cells in a petri dish to CMIT, those cells showed signs of neurotoxicity.
These two examples are not typical for an ordinary skin care customer, but they do demonstrate these are powerful chemicals.
On the other hand, if you're not allergic, they are considered relatively safe. We don't know of them causing any chronic, long-term health problems.
Conclusion
The Environmental Working Group classifies these chemicals as Unacceptable.
Therefore, avoiding MCI and MIT is recommended.
Look on Your Labels
First, do NOT accept self-labeled products. That means, if a company claims its product is "organic," "natural" or "green" - assume they're lying, and that's all marketing.
Make sure products you apply on your skin have been tested by a respected third-party.
The highest label to watch for is "USDA Certified Organic." That's the government itself validating the product.
Also, EWG Verified, from the Environmental Working Group. They certify only products which are free of all harmful ingredients.
https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/fs_G-58_1-Oct-98.pdf
https://www.ewg.org/skindeep/ingredients/703924-METHYLCHLOROISOTHIAZOLINONE/
https://www.healthline.com/health/methylchloroisothiazolinone
https://en.wikipedia.org/wiki/Methylchloroisothiazolinone
https://www.safecosmetics.org/chemicals/methylisothiazolinone/
https://www.obelis.net/news/leave-on-products-containing-mcit-mit/