10 TENS Unit Side Effects to Consider

TENS therapy is a drug-free, affordable and effective way to manage and treat pain when needed. Although it is regarded to be very safe for most people, for some rare occasion accidents can happen. Here are some possible TENS Unit side effects. The cause and remedy are also discussed with the idea of resolving it.

Side Effects of Using TENS Unit

Skin Irritation

The patients may experience skin irritation as a side effect when using TENS. Before Placing the pads on the skin, it is important to clean the skin and make it absolutely dry. The Electrode pad comes with a sticky surface, and after use, it should be stuck back to its own sheet. These pads are supposed to be used for the same patients a number of times. If two or more persons are using the same TENS unit, it is advised to buy a separate set of electrode pads for each individual. This avoids the possibility of cross-infection.

The electrode pad being sticky tends to get contaminated after some time. On visual inspection, if found dirty, replace it with a new one. After every session, carefully check your skin for any irritation. If found, apply some skin ointment. Aloe Vera based creams are found to be effective.

In case your skin is very sensitive, you can try using hypoallergenic pads. These pads though a little expensive, are very suitable for sensitive skins.

Burn Mark

In some very rare cases, where the skin is very sensitive, or the TENS settings have been set high, the skin may burn or become red. In case you suffer such burns, discontinue the use of TENS on that part of the body and treat the skin first. If the burn is severe consult a doctor, in case it is mild, apply some burn ointment and let the skin heal, before you use TENS again.

Very closely placed pads may also lead to skin burns. Remember to place the pad at least one inch apart. Increase the distance between the pads, if a burning sensation is felt.

Next time when you use TENS, keep the setting at the lowest and gradually increase it, till comfortable. After 10-15 mins check your skin.

Muscle Twitches

In case of a very high setting in the TENS machine, the muscles may twitch hard. This may lead to discomfort. Never set the machine on high settings directly, however severe the pain may be. Always start with a low setting and gradually increase it up to a comfortable level.

Muscle Pain

This is a very rare side effect of the TENS unit, where the patient experiences muscle pain after using the TENS unit. The cause of this is the high setting of the unit. If in spite of the muscle twitch, the setting is kept high for a prolonged period, there are chances of muscle fatigue and muscle pain.

Suspend the therapy immediately and treat the muscle with some good relaxation.

Never use the TENS unit on a high setting, if you are not comfortable.

The tolerance of every individual is different, and settings should be done as per your tolerance. Using the unit at the highest setting does not mean a quick recovery. On the contrary, if it does not suit you, it might lead to complications.

Open wound aggravation.

Despite the warning not to use TENS on an open wound, sometimes due to carelessness or oversight, it may be used on an open wound.

This may aggravate the condition of the wound. Stop the therapy immediately and get your self checked by a doctor.

Facial Nerve Damage

The use of TENS on the face is not at all advised. The facial skin is very thin and delicate. The electrical impulses may impinge on the nerve with great force, and this may result in facial nerve damage.

In case the damage is done, please consult a doctor immediately.

Never use electrode pads on the face, neck, and chest.

Loss of muscle control

This can happen in the rarest of the cases. Since the muscles twitch because of the electrical impulses, sometimes it may go out of control for some time. Driving and operating any heavy machinery as you undergo the TENS therapy is strictly not advisable.


Sometimes in young patients, a feeling of nausea could be experienced. This is very temporary and will go off, on its own. One may experience this for the first time, and as the body gets used to it, it may not repeat.

In some cases, electrical impulses from the TENS unit may interfere with the autonomic nervous system. This interference may manifest itself as a feeling of nausea or giddiness.

If giddiness accompanies, nausea, then you should discontinue the use of TENS unit and consult a doctor.


It is an abnormal sensation on the skin. Sometimes it can be painful too, but generally, it is not. It is just abnormal. This is a result of the malfunction of the nervous system.

The Transcutaneous electrical impulses from the TENS unit stimulates the peripheral nerves, and this stimulation may interfere with the normal working of the nervous system. This could trigger some malfunction of the nervous system. This is a very rare occurrence.

Mild electrical shocks

The TENS unit works on very low voltage, and it is absolutely safe. However, if the skin is wet and the electrodes are stuck on it, there is a possibility of mild shock, which is definitely not fatal. But it can be uncomfortable. The pads need to be secured firmly to the skin. Loose contact may also give a feeling of electrical shock.

Dry the skin completely before placing the electrode pads on them.

Most of the above side effects are a result of a wrong setting or wrong placement of the pads. If the user exercises caution and follows the user instructions and manual carefully, most of the side effects can be avoided.

In case of any confusion, it is better to contact your doctor or the manufacturer of the unit to clarify.

The TENS unit is a very effective pain management device and if carefully used, has almost no side effects.

Why use a TENS unit?

The physical pain of some sort or the other is a common phenomenon these days. The pain could be associated with some ailment, or it could be just on its own.

A lot of people suffer from long term chronic pains of various types, like knee pain, back pain, etc.

Of all other medicines sold over the counter, the sale of pain reliever is the highest.

Many resort to some home/self-treatment and the pain subsides. Seek medical advice in case of severe pain. The treatment may be medication or surgery.

Despite all these treatments available, we still find a vast number of people afflicted by pain. They either start ignoring the pain or try to live with it. Either of this is not a healthy choice.

Pharmacological treatment and invasive procedures have their own risk.

In the year 1974, a technology-based, non-pharmacological, non-invasive, highly effective pain management therapy got introduced. This therapy named “Transcutaneous Electrical Nerve Stimulation” (TENS) is approved by USFDA as alternative pain management therapy and is very prevalent in the USA and Europe.

Highly controlled and modulated electrical impulses are applied to the affected area, and this impulse stimulates the peripheral nerves underneath the skin. And hence the name Transcutaneous Electrical Nerve Stimulation.

The TENS machine is safe and authorized for over the counter sales.

The primary reasons for the popularity of this therapy

  1. It is a compact portable device, the size of the cellular phone and can carry easily.
  2. It is straightforward to operate, and the patient himself can self-administer the therapy, without the need for any professional or assistance.
  3. It is useful in different kinds of pain, both chronic pain as well as acute pain.
  4. You can use TENS along with your routine medical treatment.
  5. It is economical too.

The TENS UNIT is handy in different types of pains

  1. Back Pain
  2. Knee joint pain
  3. Sciatica
  4. Post-operative pains
  5. Labor pains
  6. Sports injuries
  7. Migraine

And many more.

How does TENS Unit Manage Pain?

The TENS therapy machine mainly consists of a base unit, electrode pads (2 or 4 pads) and connecting wires. The base unit sends controlled and modulated small electrical impulses to the electrode pads and these travels subcutaneously to the peripheral nerves. The stimulation of the peripheral nerves relieves pain based on the following two theories.


Whenever any mild or dull stimulus reaches the peripheral nerves, it results in blockage of the prevalent pain signal in reaching the brain. The brain does not felt severe pain, it registers the tingling sensation or twitching of the muscles, which happens because of TENS.


The theory states that the stimulation of the nerves induces the secretion of endorphins in the body. Endorphin is a natural pain reliever, and because of this, the pain subsides.

TENS therapy have little side effects for anyone except

Persons with a pacemaker or any other electronic implants in their bodies.

TENS machine emits electrical pulses, and there is always a probability and danger that these impulses may hamper the working of electronic implants.

It can be dangerous sometimes hence it is not advised for persons carrying implants in their body.

Persons suffering from epilepsy

Due to the electrical impulse, not only the nerves get stimulated, but the adjoining muscles also get stimulated, and they begin to twitch. The twitch is very prominent sometimes. Epilepsy is a sensory and nervous system disorder, and TENS also works on the sensory system. This may aggravate the situation. Hence TENS is not advised in epilepsy.

Pregnant women

Any kind of radiation or electrical impulse poses a danger to the fetus. The development stage of the fetus is very sensitive, and any external radiation or impulse may result in some long-term disorder.

Pregnant women should avoid TENS therapy.

People diagnosed with cancer

Strong evidence is in favor of the fact that the tumor tends to grow because of the electrical stimulation. TENS also delivers an electrical impulse to the body.

Keeping this in mind, cancer patients are advised not to use TENS.

Should not be used on open wounds or broken skin

The wound gets aggravated on exposure to the electrical impulses. So care must be taken to avoid usage of TENs on open wounds or cut skin.

Diabetic patients should consult their doctor and take medical advice before resorting to TENS therapy

For most of the patients, TENS therapy turns out to be very a safe option with no side effects.