What to Know About Ab Stimulators

Ab stimulators, a type of electronic muscle stimulator, are devices that can make your abdominal muscles appear firmer and more toned by electronically stimulating them.

However, they won’t help you lose weight, or get “rock hard” abs without diet and exercise. And ab stimulators, especially those that aren't approved by the FDA, have some risks.

What Are Electronic Muscle Stimulators?

Electronic muscle stimulators work by sending electrical signals to contract your muscles. They’re often used for physical therapy or rehab.

Physical therapists have used this type of training since the 1960s to improve and maintain muscle strength after surgery. In the former Soviet Union, elite athletes saw 30% to 40% improvements in strength, which suggests this form of stimulation may be more effective than exercise alone.

Doctors can prescribe them to help people recover muscle strength after:

  • A stroke
  • Major surgery
  • Serious injury

Doctors may also prescribe medical muscle stimulators to prevent muscle atrophy and relax muscle spasms.

What Are Ab Stimulators?

Ab stimulators are electronic muscle stimulators that focus on your core.

The FDA has approved one over-the-counter ab stimulator, the Slendertone Flex, sold by BMR neuroTech Inc. It’s approved for toning, firming, and strengthening ab muscles.

Benefits of Using Ab Stimulators

Research has shown that electrical stimulation training can boost muscle endurance as well as strength. In one small study, people using ab stimulators also saw small decreases in waist size, even when their weight stayed the same.

In the 2005 study, 24 adults were separated into two groups. One group used ab stimulators five days a week for eight weeks, while the other did not. Neither group did any abdominal exercises. 

Those who used ab stimulators had improved posture and a 58% increase in abdominal strength. They also saw a 100% increase in abdominal endurance and reduced their waists by an average of 3.5 centimeters (about 1 ⅓ inch). All the people who used ab stimulators said their posture had improved and that their abdominal muscles were firmer and more toned.

Because this study was small, it’s not conclusive. A more recent study, which was also small, found that electronic muscle stimulation didn’t significantly change trained athletes’ abdominal muscles.

Unless you eat healthfully and exercise regularly, there’s no evidence that using an ab stimulator will make a big change in your appearance.

Risks of Using Ab Stimulators

Using ab stimulators carries several risks, particularly if you use a device that hasn’t been approved by the FDA.

Unregulated ab stimulators. You can buy many ab stimulators on the internet that aren’t FDA-approved. They may or may not be safe. They could be improperly manufactured, designed, or labeled.

Unregulated ab stimulators carry a risk of:

  • Burns
  • Bruises
  • Skin irritation
  • Electrical shock
  • Problems when you use them with other medical devices, like pacemakers

Regulated ab stimulators. There are risks even if you use an approved stimulator. They include interference with other medical devices such as implanted defibrillators and pacemakers.

If you have a problem with your ab stimulator, report it to the manufacturer. You should also report it to the FDA’s reporting program, MedWatch, by calling 1-800-FDA-1088, faxing the agency at 1-800-FDA-0178, or filing a complaint through its website.

Show Sources


Journal of Rehabilitation and Assistive Technologies Engineering: “The safety of electrical stimulation in patients with pacemakers and implantable cardioverter defibrillators: A systematic review.”

Journal of Sports Science & Medicine: “The Effects of Neuromuscular Electrical Stimulation Training on Abdominal Strength, Endurance, and Selected Anthropometric Measures.”

Physiological Reviews: “Regulation of Increased Blood Flow (Hyperemia) to Muscles During Exercise: A Hierarchy of Competing Physiological Needs.”

PLOS One: “Effects of neuromuscular electrical stimulation training on muscle size in collegiate track and field athletes.”

‌FDA: “Electronic Muscle Stimulators.”

© 2020 WebMD, LLC. All rights reserved. View privacy policy and trust info