TENS Safety: Who Shouldn't Use a TENS Unit?

Before deciding on a TENS unit, you should be aware of potential risks and safety measures you should take.

In general, TENS units are considered a very safe treatment option and are nearly side effect free. Side effects from using TENS units are not very common; however, those with certain conditions should not use them.

Contraindications For Electric Therapy

Those with a Pacemaker or Heart Disease

Heart Disease

One of the potential TENS therapy side effects is that it interferes with implanted medical devices. If you have a pacemaker or have heart disease, you should avoid using a TENS unit.

The electrical current from the TENS unit could disrupt the functionality your pacemaker, potentially ruining the pacemaker and putting yourself at risk.

Certain pacemakers are able to be used with a TENS unit, but it's best to talk to your health care professional about that first.

If You Are Pregnant

Pregnant Woman

Another one of the dangers of using electrical muscle stimulation is that pregnant women shouldn't use it.

To clarify, there is actually no risk to the pregnant woman using electrotherapy. However, the effects of electrotherapy on the unborn child are unknown and should be avoided.

It's still possible to use electrotherapy while pregnant under the supervision of a health care professional. But even then, it should never be used before the third trimester and the electrodes should never be placed above the uterus.


It's possible that the electrical current could trigger and epileptic episode. However, the research around electrotherapy for those with epilepsy is still inconclusive.

Some sources say it's ok, and others say to practice caution. Regardless, most TENS units come with a warning that says it should not be used by epileptics.

To be on the safe side, if you have epilepsy, you should practice caution while using a TENS unit or consider not using it at all.

Pain in Head and Neck

Many people use electrical stimulation to relieve neck pain, but there are some who should never use electrotherapy on their neck. Those are people who suffer from seizures, convulsion’s or blood clots.

Regardless of those conditions, you should never place the electrodes anywhere on your head unless the device is specifically intended for that purpose. If you are suffering from migraine, check out the Cefaly TENS unit which is specially designed for headaches and migraine pain


Those suffering from Lymphedema should not use a TENS unit.

TENS treatment affects the circulatory system and potentially cause problems for the lymphatic system and cause even more fluid retention.

Additionally, Lymphedema can cause skin swelling and compromise the skin's integrity. TENS units should only be used on healthy skin.


If you aren't dealing with any of the above conditions, TENS units can be a great way to get safe and effective pain relief.

Buying your first TENS unit can be tricky, especially if you're unfamiliar with electrotherapy. There are many models with many different features out there.

We recommend checking out our reviews page for information on the best and most popular TENS units. Your experience with TENS units will be much better if you have one that matches your particular needs.

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