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Having just reviewed Slendertone, checking out The Flex Belt was like déjà vu. Seeing Flex Belt claim it was the first US Food and Drug Administration (FDA)-approved electronic muscle stimulation (EMS) belt for direct consumer sales—the exact same claim as Slendertone—my radar went off. A quick dive into the Flex Belt website confirmed my suspicions : Slendertone makes the Flex Belt, but doesn’t sell it. It’s that simple. 
Slendertone Distribution, Inc opened in 2006. It’s headquartered in Hoboken, New Jersey, and has an A-minus rating from the Better Business Bureau (no reviews, 1 complaint not responded to). The Flex Belt distribution itself is out of Malibu, California, and their customer service contact is 855-353-9432.  
Like all medical-grade EMS devices, The Flex Belt stimulates the nerves that make your muscles contract and relax; an abdominal workout without working out. The FDA cleared it for sale to everyday folks because it actually works to strengthen, tone and tighten the abdominals. And it can benefit people who suffer with low back pain and other conditions that prevent them from working their abs. So that’s all good.
What an ab belt is not is a weight-loss device. Yes, you can have a little extra—I repeat, a little extra—around the middle and find success with the Flex Belt. But if that subcutaneous fat layer is too thick, it doesn’t matter that it’s stronger, more powerful—penetrating thick layers of fat is a task and a half. Just look at the before and after images on the Flex Belt website; virtually no user has a blubbery belly. So, if you’re interested in getting ripped abs—which some claim they get with the Flex Belt—lose some tummy fat first and then strap it on.
From The Flex Belt itself: “It is important to note that people who have several inches of stomach fat do not feel the intensity near as much as those who have less stomach fat because the extra fat makes the muscles harder to reach.” 
The Flex Belt costs $150; the Slendertone $100. The “intensity level” difference depends on the user.
The Flex Belt Claims
The Flex Belt says it itself: it and Slendertone are the same thing, just The Flex Belt is a better version. The only other difference is you cannot buy The Flex Belt on the Slendertone website.
So what’s better? The Flex Belt says it’s 50 percent stronger than Slendertone, since its intensity can be adjusted to 150, not just 99 like Slendertone. The Flex Belt has three more training programs, a different label, and costs more because “it is a more expensive belt to produce.” And it comes with other extras, including a one-year subscription to either Elle or Maxim magazine and a meal-planning app The Flex Belt claims “goes far beyond basic food journaling.”
The Flex Belt Meal Planner uses artificial intelligence (inspired by NASA robotic technology) to allow users to see deficiencies and weaknesses in their nutrition, and learn how to correct them. 
The Science Behind The Flex Belt
The science behind EMS devices is pretty solid. Despite being commissioned by Slendertone, an apparently unbiased study conducted by the University of Wisconsin-LaCrosse and then published in the Journal of Sports Science and Medicine shows conclusively that the technology in Slendertone and The Flex Belt does work, and that the more intense the electrically-induced contractions, the more effective the results. Hence the FDA clearance.
The study found that the ab belt “…as used in the current study, resulted in significant improvements in the muscular strength and endurance of the abdominal region, as well as subject’s perceived shape and satisfaction of the mid-section.” 
It works to tone muscle and improve muscle strength and health. But what it does not do is help people lose any weight—though neither The Flex Belt nor Slendertone ever claim that it does.
In fact, as The Flex Belt points out, muscles are pretty hard to get to behind a thick coating of stomach flab, be it level 1 or level 150. The belt must have access to the muscle to do any good, and with pounds and pounds of belly fat—as is often the case with people trying to lose weight, especially around the middle—it just won’t cut it. The Flex Belt admits as much.
Also…it’s not a perfect science. From an article on MedicineNet.com which refers to a number of FDA concerns regarding EMS devices (The Flex Belt and Slendertone are never mentioned—and if they didn’t have FDA clearance, they’d be in trouble for claiming so on their website):
While an EMS device may be able to temporarily strengthen, tone or firm a muscle, no EMS devices have been cleared at this time for weight loss, girth reduction, or for obtaining “rock hard” abs. 
FDA has received reports of shocks, burns, bruising, skin irritation, and pain associated with the use of some of these devices. There have been a few recent reports of interference with implanted devices such as pacemakers and defibrillators. Some injuries required hospital treatment. It is very important that these devices be properly designed, manufactured, and labeled with clear and complete instructions for use and that anyone using them follows the instructions carefully. 
Word on the Street About The Flex Belt
So here’s the thing about The Flex Belt’s reviews: when you have endorsements by B-list celebrities, disc jockeys, men’s and women’s magazines and the like (surely some, if not all, paid) plus a dynamic website, lots of great infographics, facts, science, testimonials, how-to videos, before/after pictures, and more—it’s clear the product has been pretty well hyped and marketed.
But what do actual users say?
First, although The Flex Belt’s website sells the belt for $150, it sells for $200 on Amazon.com. Reviewers are somewhere between ‘Meh’ and ‘Yeah!’ Nearly 1,000 users gave the Flex Belt an average rating of 3.5 stars out of 5. 
Starting with the 1-star reviews, most of the complaints had to do with belt function or malfunction, with a few complaining that if you have a belly or a “muffin top” the current doesn’t reach the abs through the fat—which The Flex Belt already admits.
We’ll look at a 1-star, a 3-star and a 5-star for perspective, keeping in mind more than 60 percent of Amazon reviewers gave The Flex Belt 5 stars.
Reviewer “Steven” warns (2017, 1-star), “Do not buy. Does not hit all abs like commercial says. Have gone through all settings. Within a week I had it maxed out at 150. Do not purchase.” 
“David W. Hatchett” makes a good point (2014, 3-star): “Ok…I guess. Product works…just not sure it does much. Crunches are harder, but clearly work better. I guess if 6-packs were easy, everyone would have them.” 
“Shahar Zoleha” raves in a very recent review (2017, 5-star): “It’s absolutely amazing. Strengthens my core without exercising. This is not a diet gadget nor a weight loss program. It doesn’t burn fat and it doesn’t tell jokes. It only strengthens my core.. which is all i need it to do. I burn fat with muscle movement and that’s enough to get me a six pack.” 
Heads-up—The Flex Belt isn’t sold at Wal-Mart but first cousin Slendertone is, and the reviews are just okay.
“Alisha86” gave it 4 stars (2017): “I dont know yet if it works to build abs but I have noticed that I have less pain in my back (I alternate stomach and back). It works relatively the same as a tensing unit at the dr office for musle pain.” 
“runtell” gave another Slendertone model (there are several similar) 5 stars (2016): “Being older I have not been rushing my progress…its only been 10 days but I have noticed a difference..enough of a difference that I have already ordered 2 sets of replacement pads as they are presently on sale. To say I am pleased with the results so far would be an understatement…Being able to adjust to levels that are comfortable to me makes all the difference in the world..it does work and have already recommended and bragged about to friends.” 
The Bottom Line: Is The Flex Belt Worth a Try?
Depends.If you have a belly that’s not too flabby, go for it. The test seems fairly simple, based on reviews and The Flex Belt itself: if you can’t feel the contractions in your abdominals, The Flex Belt is really not for you. The $150 to $200 would be better spent on running shoes or a gym membership.
Best advice? If it’s strong and toned abs you want (and who doesn’t?), lose the belly fat first then maybe go for it. Otherwise, steer clear. You’ll be wasting your money. But you people with little tummies? Belt up.
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