Some experts recommend using a transcutaneous electrical nerve stimulation (TENS) unit with four electrodes placed on your lower abdomen and back for constipation relief. But research has revealed other successful setups.

TENS units are small, battery-operated devices you can use to treat various conditions, including constipation.

TENS units transmit low voltage electrical current into the skin through sticky pads called electrodes that you place strategically on various body areas. The electrode placement determines the path of the electrical impulses.

TENS machines are designed to reduce or block pain signal transmissions to the spinal cord and brain. This temporarily relieves muscle spasms and pain in targeted body parts.

Physical therapists often use TENS units to treat various conditions, including back pain and injuries.

This article explains how to use a TENS unit to treat constipation at home.

To treat constipation, you can place TENS electrode pads in several ways. You can experiment to see what works best for you. If working with a healthcare professional, they may have input on where to place the sticky pads.

Some therapists recommend placing two sticky pads on either side of the lower abdomen and two on either side of the lower back.

For example, in a small 2016 study involving children with treatment-resistant, slow-transit constipation, participants used four TENS electrode pads so currents crossed the lower abdomen. Using this setup for 1 hour daily for 3 months reduced constipation in more than 50% of study participants.

placement of TENS unit electrodes for constipation reliefShare on Pinterest
Illustrated by Jason Hoffman

Some studies indicate that alternate electrode pad placements may also help relieve constipation.

For example, a small 2022 study analyzed the effects of transcutaneous electrical acustimulation (TEA) in people with irritable bowel syndrome with constipation. Participants used four TENS electrode pads — two on the inside of each wrist, about 1.5 inches beneath the wrist crease, and two on the front of the shin muscle of each lower leg.

The researchers found that TEA helped stimulate the vagus nerve, accelerate bowel movements, and reduce constipation and pain.

To use a TENS unit for constipation, follow these tips:

  • Ensure you turn the TENS unit off when you attach the electrodes to your bare skin.
  • Do not position the sticky pads on broken or irritated skin patches.
  • Avoid mucous membranes such as the urethra, rectum, and vagina.
  • To protect your skin from pulling, you can shave it first if you have hair in the area.
  • After placing the electrodes, turn the unit on. You should feel a slight tingling sensation.
  • You can adjust the electrical stimulation level by turning a dial on the unit.
  • Maintain a comfortable level that feels tingly but not painful.

People typically use TENS machines for 20–30 minutes at a time. You can use your machine several times daily if you choose. Talk with a healthcare professional about the intensity level and treatment duration that makes sense for you.

Who should not use TENS?

TENS machines are not safe for everyone. Talk with a healthcare professional before using if you:

  • are pregnant, breastfeeding, or chestfeeding
  • plan to become pregnant
  • use an electrical or metal implant, such as a pacemaker
  • have epilepsy or heart disease
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What nerves stimulate bowel movements?

The enteric nervous system (ENS) in the walls of the gastrointestinal tract controls your bowel movements. The ENS regulates the contractions that move food through your bowels. It also regulates sphincter control using signals the brain and spinal cord generate.

Other nerves that support bowel movement function are the cauda equina at the bottom of your spinal cord and the pudendal nerve in the back of your pelvis.

Does TENS have FDA approval to treat constipation?

TENS units still need Food and Drug Administration (FDA) approval for treating constipation. This doesn’t mean you can’t use them for this purpose.

TENS units are Class II medical devices, which require manufacturers to prove to the FDA that their devices are as safe and effective as other similar devices. They don’t need to prove that the devices are effective for treating a specific condition.

Several manufacturers have received clearance to sell TENS devices. Before you buy, check to see whether the FDA has cleared the device you’re interested in for sale.

Do I need a prescription to use a TENS device?

Manufacturers can sell TENS units with and without a prescription. Some prescription-only devices deliver higher electrical current levels than over-the-counter devices for at-home use.

Some insurance plans may cover prescription-only devices.

You can use your accounts for health savings and flexible spending to pay for nonprescription units.

Studies have shown TENS units may help relieve constipation. The most recommended placement of TENS electrodes for this purpose is to use two on the lower abdomen and two on your lower back. But there are other arrangements you can try, including using only two electrodes.

Before using a TENS unit for constipation or any other condition, discuss its use with a healthcare professional. They can help you determine whether a TENS unit is a good choice for you and provide input on how to use it effectively. They can also help you decide whether additional treatments would be helpful.