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Fitness websites and social media serve up a steady helping of advertisements for ab stimulators. These devices promise to strengthen the abdominal muscles via electrical stimulation. While ab stimulators can force the abdominal muscles to contract, they will not burn fat or cause significant weight loss.
Very little research has assessed how well ab stimulators work for toning muscles. We look at the evidence to support their use and explain alternative ways to strengthen the abdominal muscles.
Doctors and physical therapists have used electrical devices to treat injured or paralyzed muscles for decades. Functional electrical stimulation (FES) uses an electrical pulse to force muscles to contract. By doing this, it prevents muscle wasting and encourages blood flow to the muscles. It may also help repair damage.
More recently, ab stimulator manufacturers have begun selling these devices to the general public. Some companies claim that their devices support weight loss or build strong ab muscles without requiring exercise. However, there is no evidence that a muscle stimulator can substantially change a person’s body.
The Food and Drug Administration (FDA) regulate these devices as medical devices, but some manufacturers — especially outside the United States — now sell unregulated devices.
FES works well as a physical therapy tool for people with serious muscle injuries.
For example, a doctor might recommend ab stimulation following a spinal cord injury to restore some abdominal muscle function and help a person breathe on their own. A 2016 review of 14 previous studies found that, following FES, people with spinal cord injuries were better able to breathe on their own than those acting as controls.
There is less evidence that abdominal stimulators can train the abs in people seeking increased muscle strength, better posture, or a slimmer waistline. The limited research that has looked at these devices has reported very small changes that were insufficient to change a person’s appearance significantly.
For example, a 2005 study followed 24 adults who did no exercise but used ab stimulators 5 days per week for 8 weeks. Each session lasted for 20–40 minutes. The researchers compared them with 16 adults who neither used ab stimulators nor did any ab exercises for the study period.
The study group had a 58% increase in ab strength, which the team measured using an isokinetic dynamometer. A curl-up test showed that these individuals had a 100% increase in abdominal endurance, compared with a 28% increase in the control group.
The study group also had an average 3.5-centimeter (1.4-inch) decrease in waist circumference. All 24 people in the stimulation group said that their abs were more toned, and 54% reported that their posture had improved. The control group did not report similar outcomes and had no reduction in waist circumference.
These findings suggest that ab stimulators might improve strength and posture while offering a very small change in waist size. However, the study was very small, and researchers have not replicated it. Therefore, it is impossible to draw strong scientific conclusions about the effectiveness of ab stimulators.
A more recent study involving trained athletes found that 12 weeks of FES did not increase the size of the abdominal muscles.
Although the evidence that ab stimulators work well for toning the muscles is weak, FDA-regulated stimulators are safe to try.
Ab stimulators cannot burn fat. To burn fat, a person must create a calorie deficit, using more calories through exercise and movement than they eat each day. Even when ab stimulators do slightly strengthen muscles, therefore, a person will not notice a difference in their appearance if they are not also burning fat.
Some of the most popular ab stimulators are available online, with reviewers promising rapid results and significant changes in body shape.
However, many of these reviews are fake. People should be especially mindful of short reviews, reviews that make extreme claims, and reviewers who have not reviewed other products or leave five stars for every product. Fakespot and ReviewMeta are examples of sites that can help with detecting fake online reviews.
Most ab stimulators are adhesive pieces of cloth that a person sticks to their abs. Each portion of the cloth delivers an electric current to the abdominal muscles, causing contractions that a person might not even feel.
Some stimulators are belts that require no adhesive and wrap around the body. These may stimulate only the abs, or they might also stimulate the back.
A few stimulators offer apps to track progress, and most allow a user to adjust the intensity of muscle contractions. The stimulator should not hurt, sting, or burn, and it should not cause muscle spasms.
Unregulated ab stimulators present the most significant risk. These devices may burn the skin, contain toxic chemicals or adhesives, or deliver a shock that is too intense to be safe.
Even FDA-regulated stimulators, however, present some dangers. These devices may interfere with other electrical devices, such as pacemakers. They may also cause a person to believe that they are getting exercise or doing something healthful, deterring them from more beneficial exercise and lifestyle changes.
People who wish to improve their posture or address muscle injuries should consider physical therapy. A physical therapist offers targeted exercises and massage. They may also recommend electrical stimulation to improve muscle health.
People seeking a more muscular core or a trimmer waistline should focus on two goals:
Burning fat by creating a caloric deficit
A person must use more calories than they eat to create a deficit. Increasing their activity level — with both intense exercise and more overall movement, such as by walking each day — can help a person gradually burn fat, including on the stomach.
Strengthening the abdominal muscles with targeted exercises
These exercises will not burn fat, but they can improve posture and core strength while making the muscles more visible as a person loses body fat. According to an American Council on Exercise study, the three most effective ab exercises are the bicycle, the crunch on an exercise ball, and the captain’s chair.
Ab stimulators offer a promise that is too good to be true: toned abs and a trim waistline without any additional work.
While an electrical current can contract the abs and slightly improve muscle health, it will not dramatically change a person’s body.
People seeking stronger abs and better overall health should talk to a doctor, physical therapist, or dietitian.