Oh. My. Word. Negative ion "health" bracelets are made with radioactive materials.

(Not the best source imaginable, but they seem to have the basic facts.)

You've probably seen negative ion bracelets before: colorful loops of silicon promoting the ability to increase balance, reduce pain and restore energy. They promise you'll run faster and jump higher. Golfers love them. Your uncle who owns a boat probably has a few in the color navy.

But we have bad news: Folks who wear negative-ion bracelets are getting three times more radiation every day than the average American.
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While the bands don't give off an outright dangerous level of radiation, anyone wearing them needs to know they dramatically increase your personal exposure to radioactivity — especially if you wear one all the time. "If someone wore that band for 24 hours a day, 365 days per year, the approximate dose ... equates to about 3.5 times the dose the average American receives [annually]," Emery told Mic.

Scientists are catching on to the risks: In fact, Israel banned these wristbands because it was concerned with irradiating citizens. In November 2015, a team of researchers from Nuclear Research Centre Negev in Israel published a study on rubber "balance bracelets" being a source of uranium and thorium, both radioactive isotopes.
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NRC staff experts on radiation worked with federal agencies and state regulators to determine the most appropriate path forward," Holahan wrote in 2014. "Products containing negative ion technology — that is to say containing licensable amounts of radioactive material — should not be sold at the present time because they have not been licensed, as required, by the NRC. ... If you have them or know someone who does, our best advice is to throw them away."

A year and a half later, the wristbands are still on the market. In China, a product marketed as negative ion powder was being put in the negative ion wristbands, Graafstra told Mic. "It's basically crushed-up radioactive waste from things like mining. It's in things like A/C filters and laundry sheets. Which is fine because, if it's not on your skin, it's not a danger. But when it touches, [the radiation] is pretty intense."
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more: https://mic.com/articles/132638/bad-news-those-popular-magnet-therapy-bands-are-secretly-sending-radiation-into-your-body#.fCDmft5BM

Here's an example: https://www.amazon.com/dp/B00BG24KPC/ref=asc_df_B00BG24KPC5034811/?tag=hyprod-20&creative=395033&creativeASIN=B00BG24KPC&linkCode=df0&hvadid=168243527467&hvpos=2o17&hvnetw=g&hvrand=11340542965221605937&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9012720&hvtargid=pla-334598028634

Googling "germanium" will locate a lot of similar "health" products. I have no idea why germanium got chosen for this honor, except that most people have never heard of it and so will believe anything about it.