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Sad but true: Personal care and beauty products are pretty unregulated and also chock-full of confusing chemical names. Who knows what all of those weird-sounding ingredients actually do? Your best bet is to find a shampoo that doesn't contain suspicious ingredients — stuff that poses some sort of health concern, is an allergy trigger or is just too harsh on your hair.
Methylisothiazolinone, or MIT, has been shown to disrupt communication between neurons by the National Institutes of Health, according to NaturalNews.com. There's no confirmation that MIT causes actual health problems outside the test tube yet, but researchers are nonetheless concerned about its neurotoxic potential. It's a common allergen and may disrupt the immune system, too. So why is it in your shampoo? It's used as a preservative.
Parabens are chemicals that act as estrogen mimics, which means they may disrupt your reproductive hormonal functions and cause a range of disorders as a result. Parabens have been found in breast-cancer tumors, although it's not clear why. Parabens are in your shampoo because they also act as a preservative.
Avoid: PEG/Ceteareth/Polyethylene Compounds
In this case, the problem isn't the chemical itself, but rather a contaminant. A carcinogen known as 1,4-dioxane is commonly found contaminating shampoos and other cosmetics that contain polyethelene, ceteareths or PEGs.
Avoid: DMDM Hydantoin
DMDM hydantoin is another preservative used in shampoos and other cosmetics. When it breaks down, though, it produces formaldehyde. That's right, the same chemical they use to pickle dead things in a jar. Formaldehyde is a formidable allergen.
The problem with "fragrance" is that it's vague. It's impossible to tell what ingredients an added fragrance are made of, and some can contain really scary stuff. Artificial fragrances can cause serious allergic reactions. Some of their ingredients may disrupt hormone function. Fragrance-free is your best bet; products that get their natural scent from herbal ingredients or essential oils are a good second choice.
Avoid: Sodium Laureth Sulfate and Sodium Lauryl Sulfate
These two chemicals are simply harsh. Harsh on your hair, harsh on your skin. They're heavy-duty detergents that help your shampoo get all foamy and sudsy, but also strip your hair not only of dirt but its natural oils and moisture. They're also a major irritant — one of the reasons why getting shampoo in the eye stings so much, in fact.
What to Look For
Seek out shampoos that not only avoid these nasty chemicals but show a commitment to natural ingredients whose names you can pronounce. Try a shampoo bar or a castile-soap shampoo. Look for shampoos labeled fragrance-free and hypoallergenic, but check the labels. Organic ingredients are nice for the environment but their presence doesn't necessarily mean a shampoo is safer.