The Flex Belt is has been approved by the FDA for use as an abdominal muscle toning product. The Flex Belt Report and the Flex Belt website suggest that the Flex Belt is safe for use by people of all ages and fitness levels.
This device is intended to help tone the abdominal muscles by sending electrical impulses to the nerves around the abdomen, making the muscles contract and relax even while the wearer is not otherwise active. It is not intended as a weight loss aid.
Most of the user reviews on Amazon suggest that the Flex Belt is effective at toning the abdominal muscles provided the user already maintains a healthy lifestyle and body weight.