Still, that’s not to say that even the projects that get delayed or turn out to be duds amount to blatant hucksterism. Kickstarter and Indiegogo both have fraud protections in place, but an Indiegogo representative told me the company doesn’t independently vet the medical claims of projects on the site.

It’s hard to know, Haensly said, “How much of [the faulty projects] are outright fraud, how much is exuberant optimism, and how much is ignorance about how much it takes to take a project through manufacturing. I would like to believe that the majority are put up in good faith, but there’s a high likelihood of hitting a speed bump along the way. Medical devices are even harder.”

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Start-ups are notoriously secretive about their inner-workings, and founders who believe they’re sitting on revolutionary technology are even more protective. One complaint by PandoDaily’s Robinson and others is that tech journalists often can’t get their hands on crowd-funded devices until their campaigns have already been fulfilled. That means knowing whether the devices are genuine requires waiting for them to ship to consumers—which also usually means thousands of people have already opened their wallets.

Last month, Christian Brazil Bautista, a writer for Digital Trends, said he saw a live, working demonstration of the GoBe, though he was not allowed to wear the device himself:

Healbe Managing Director George Mikaberydze ingested a can of Mountain Dew, and then observed as the bracelet detected that he had ingested a lot of sugar. When he took it off on our request, we saw his glucose levels fall to zero on a companion iPhone app. He put the bracelet back on. They soared again.

In an email, HealBe told me that they are still conducting research to substantiate the legitimacy of the Flow technology, and they they plan to demonstrate the GoBe before an audience later this month.

“New ideas are often met with skepticism,” the company told me. “We anticipated critics when introducing such a groundbreaking device into the market. We understand that ‘seeing is believing’ and expect opinions to change once the device and research results are available.”

I independently contacted a number of experts who specialize in metabolism, and none could vouch for the science behind the GoBe.

“While the idea is laudatory, it seems primitive and lacks appreciation of the body complexities (not even commenting on the fact that we are all different),” said George Grunberger, an endocrinologist who runs a diabetes center in Michigan.

Yoni Freedhoff, a weight-management specialist and an assistant professor of family medicine at the University of Ottawa, said in an email:

Even were GoBe to beat the odds and truly deliver what would amount to be a world-changing technology, the leap from the measurement of blood or cellular glucose to its translation into calories consumed is about as probable as a human powered leap across the grand canyon. Simply put, not only would the algorithm required to deliver those results differ between individuals due to variations in insulin sensitivity, they would even differ within individuals depending on the composition of the foods they consumed, their activity levels and their body compositions.

Indiegogo contributions are nonrefundable, and the company advises donors to take their refund requests up with the individual start-ups. The Indiegogo rep suggested that donations should not be seen as an exchange of money for a product, per se:

There are many facets to a campaign and crowdfunding is more than just a simple purchase of a perk. What's important is that the campaigner has clear communication during and after their campaign and be in constant contact with their audience. This can help alleviate problems and questions surrounding delivery.

Then again, not all products use crowdfunding sites just to get from idea to iTunes store. Some take their Indiegogo buzz to investors or medical manufacturers in an attempt to drum up larger sums of capital, Haensly said.