"Gluten-free" is a huge buzzword right now–but it's not limited to food: Beauty companies are increasingly labeling products gluten-free. The other day I was in Whole Foods, and there was an entire display of "GLUTEN FREE!" hand soap. But is gluten in cosmetics something we even need to worry about? Between lead in my lipstick and formaldehyde in my hair straightener, I'm not sure I have the capacity for more beauty product-related anxiety.

Dr. Peter Green, director of the Celiac Disease Center at New York-Presbyterian Hospital and Columbia University Medical Center, laid out for me why gluten's been getting such a bad rap as of late. Gluten, a protein found in wheat, rye, and barley, originally gained notoriety because it exacerbates an autoimmune disease called celiac disease. You can only conclusively diagnose celiac disease with a blood test and biopsy–and eating a gluten-free diet is the best way to control symptoms. (According to the NIH, about 1 in 141 people suffer from celiac disease, many undiagnosed.)

Then there are gluten allergies. Wheat is a known allergen, and people with wheat allergies will have a bad response as soon as they eat it. Allergies are harder to diagnose via blood test, but there are some non-specific tests that can at least give you an idea if you're allergic. (If you want more info about the science behind gluten, Slate wrote a fantastic article a few months ago.)

Finally, there are those who suffer from "gluten sensitivity," which is very different from the previous two gluten-related diseases. The increase in so-called gluten sensitivities is what's driving the gluten-free market right now, and it's a grey area in the whole gluten conglomerate.

"Gluten sensitivity is a self-diagnosis. It's not a medical diagnosis and it's based on people who claim to feel better [when they don't eat gluten]," Dr. Green told me. "But when we see them in the celiac center, we try to make an alternative diagnosis."

There's no conclusive test for sensitivity, and gastroenterologists don't even agree on its existence. But a lot of people have started adapting a gluten-free lifestyle because it makes them feel better, which leads to a higher demand–hence all those gluten-free products.

Which brings us to beauty. According to Dr. Green, the only people who should really avoid products containing gluten are those with documented wheat allergies.

"We think that people who have celiac disease don't have to avoid skin contact with gluten," Dr. Green said. "There are currently no studies, but we think you've got to ingest it or inhale it for it to cause a reaction."
The two product exceptions? Lipstick (because you actually swallow it, which... ew) and hair spray, though Dr. Green thinks the risk of a celiac flare is low with a spritz or two of hairspray.

Not that many beauty products actually contain gluten in the first place. "It's not really common for cosmetics to contain gluten," cosmetic chemist Ni'Kita Wilson told me. "There are so many ingredients that are used in skin care–wheat based products aren't typically the first choice." Basically, a lot of it's just marketing. Remember the fat-free craze in the '90s? Even things that never had fat in the first place (like my favorite candy ever, the red Swedish Fish) were advertised as fat-free.
"We are in the era of 'free' marketing: paraben-free, fragrance-free, oil-free and now the newest addition to the family is gluten-free," Wilson said. "This claim is becoming a frequent request–so yes, the beauty industry is moving in a gluten-free direction."

If you are interested in avoiding gluten in your blush, there are certain products more likely to contain it. "[Sometimes] a wheat-derived or barley ingredient will be used to firm up the skin," Wilson explained. "But these ingredients are more commonly found in hair care products to increase volume, hold, or to help strengthen the hair."

Your best bet? Don't spend more for something listed as gluten-free, unless you have a legitimate medical reason for doing so. When it comes to beauty, gluten is not necessarily your enemy.
Click through to the next page for a list of potential gluten-containing ingredients (courtesy of Wilson), if you're interested in really analyzing your products.

Ingredients Potentially Containing Gluten:
Amp-Isostearoyl Hydrolyzed Wheat Protein
Barley Grass
Barley Hordeum vulgare
Disodium Wheatgermamido Peg-2 Sulfosuccinate
Hordeum Vulgare Extract
Hydrolyzed Wheat Gluten
Hydrolyzed Wheat Protein
Hydrolyzed Wheat Protein Pg-Propyl Silanetriol
Hydrolyzed Wheat Starch
Hydroxypropyltrimonium Hydrolyzed Wheat Protein
Semolina Triticum
Stearyldimoniumhydroxypropyl Hydrolyzed Wheat Protein
Triticum aestivum
Triticum carthlicum
Triticum durum
Triticum polonicum
Triticum spelta
Triticum turanicum
Triticum turgidum
Triticum Vulgare (Wheat) Flour Lipids
Triticum Vulgare (Wheat) Germ Extract
Triticum Vulgare (Wheat) Germ Oil
Wheat (Triticum Vulgare) Bran Extract
Wheat amino acids
Wheat Bran Extract
Wheat Germ Glycerides
Wheat Protein
Wheat Triticum Monococcum

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