What should you know about an FDA-approved TENS unit?

FDA clearance indicates that the device has been reviewed for its stated intended use and labeling. It does not mean the unit treats every cause of pain, works for everyone, or replaces a diagnosis. TENS sends mild electrical impulses through adhesive electrodes on the skin. People may feel tingling, tapping, or pulsing rather than a strong contraction. Relief can vary and may last only while the unit is operating or for a period afterward.

Do not place electrodes over broken, infected, or numb skin, the front or side of the neck, the head, or across the chest. A person with an implanted electrical device, a seizure disorder, reduced sensation, pregnancy, or unexplained pain should obtain individualized advice before using TENS.

Read the specific device instructions, clean and dry the skin, and begin with the lowest comfortable setting. Keep electrodes on the areas shown by a clinician or the instructions; never use the unit while driving, bathing, sleeping, or near water. Stop if it causes burning, skin irritation, dizziness, worsening pain, or unusual symptoms. Check the skin after removal and replace worn electrodes as directed.

Use TENS as one part of a plan that may include movement, rehabilitation, or treatment of the underlying problem. The [TENS Unit](/technology/tens-unit/) page explains the technology in more detail.

Arrange medical assessment for new, severe, unexplained, or persistent pain, especially when it follows an injury or comes with weakness, numbness, fever, swelling, or loss of function. Seek emergency help for chest pressure, trouble breathing, fainting, sudden one-sided weakness, or a rapidly worsening symptom. Do not use TENS to delay urgent assessment.

Ask which diagnosis the device is intended to support, where the electrodes should go, what setting and session length are suitable, and whether your medicines, skin condition, pregnancy, or implanted device changes the advice.