TENS Machine Side Effects & Warnings - You Should Know

Intensity at Home TENS Unit If you are the person who wants to purchase a TENS machine, or who have already a TENS machine but still unaware of a TENS machine side effects, this article may appear highly conducive for you.

The TENS unit machine is very suitable for a variety of pain reduction with some negligence side effects.

A tens unit is a small electric device that transmits the electrical pulses through the nerves to soothe your pain.

As a non-invasive & inexpensive tool, a TENS machine actively accomplishes its duty to stimulate the central nervous system for the blockage of pain signals to relieve pain.

Compared to other electronic devices, TENS unit side effects are relatively low in number. The TENS machine side effects involve skin irritation underpads, muscle soreness, tingling sensation & muscle twitching. The appropriate usage techniques of the TENS unit, proper pads replacement & cleanliness of your skin can ensure minimization of the TENS unit side effects. 

Here we will elucidate the TENS Unit side effects precisely.

 What is a TENS Machine?

Transcutaneous Electrical Nerve Stimulation (TENS) is a small battery-operated device that stimulates nerves with the help of a low-voltage electrical pulse for relieving pain. This machine is run by a remote that is attached to cables or wires to pads or electrodes.

With the advancement of modern technology, many manufacturers have marketed wireless TENS machines to use it anywhere secretly. For finding the best wireless TENS machine, you may check our review article on the best wireless tens unit.

In which condition TENS unit is used?

Health specialists and pain victims use TENS machines or TENS Therapy for the treatment of severe chronic pain from a series of health conditions containing: Tens Unit Electric Muscle Stimulator Machine

  • Sciatic nerve pain       
  • Headaches (tension and migraine)
  • Muscle tension
  • Neuropathy & Diabetic Neuropathy
  • Fibromyalgia
  • Back pain(hip, neck & shoulder)
  • Joint Pain & Arthritis
  • Tendonitis and bursitis
  • Post-surgical pain
  • Foot & ankle pain
  • Sports injuries
  • Menstrual cramps
  • Plantar Fasciitis

How Do TENS Machines Work?

These machines are safe & can be the alternative to non-addictive painkillers.

TENS Therapy or a TENS machine works based on two theories through which it relaxes the muscles.

  1. Gate Control Theory: The spinal cord looks like some sort of a gate that closes and opens up the current of electrical stimulation from the brain. This process takes place when the brain sends signals through the nerves. The supply of the electrical frequencies restricts the transmission of the communication while using the TENS machine; as a result, the pain signals are blocked.
  2. Endorphin Release Theory: The electrical impulses are stimulated to generate the production of encephalin and endorphins. These natural pain releasing chemicals block pain signals by acting like morphine. The process acts similar to drug therapy but does not have drug-related side effects.

The combination of the two theories provides great relief from pain. The easily adjustable settings of the TENS machine helps you to place electrodes or pads at your specified painful area & to control it according to your preference. 

TENS Machine Side Effects

Is the TENS machine out of side effects? No. Like other devices, it has some side effects, although TENS machine side effects are minimal.

The TENS unit side effects mostly reveal its nature because of some specific causes, including the overuse, inappropriate pads set up, the high-intensity level of pulse transmission, uncleanliness of skin & frequent use of it at the same place for a long time.

We are going to discuss the TENS unit side effects in the following manner:

  • Skin Irritation under Pads:

You may feel skin irritation or burning sensation in some parts of your body while using the TENS unit machine.

People who have allergic skin may experience red and irritated skin underpads. However, special pads are available for people with allergies.

This skin irritation may occur due to the improper use of it, or not cleaning the skin, or not using the gel. The long term use of it at the same place is also responsible for skin irritation.

To avoid this skin irritation, always clean your skin before applying a TENS machine & change the position of pads.

  •  Muscle Soreness:

Overuse of the TENS machine may feel your muscle soreness. The long term effect makes you feel muscle soreness as an additional condition.

Massage therapists or physicians often suggest not using it for more than a few hours at a time. If you feel sore on your muscle, use your TENS machine for several hours with regular intervals.

  • Tingling Sensation & Muscle Twitching:

Muscle twitching may arise during the use of a TENS unit device. As a result, you may have an unpleasant situation. This can occur if you set the TENS machine too high. Excessive intensity renders extreme tingling sensation that causes muscle twitching.

The high-intensity level of the machine may deteriorate the condition by creating muscle pain, or increasing pain and muscle soreness as well.

 To solve this problem, try to set your TENS device not too high & make sure you are starting at zero. Raise your intensity level until you get a moderate, tingling sensation. This gentle tingling sensation helps you releasing pain. And if you experience twitching on your muscle, you may put it off, or you may stop the machine.

  • Allergic Sensation:

You may experience an allergic sensation under the pads of your TENS machine. This can happen if you have sensitive skin with allergy, or if you do not change the conductive gel for several times.

As a remedy for this, you need to change your conductive gel and keep the skin clean. Various manufacturers have fabricated special pads for allergic people.

Is it true that the TENS unit causing muscle spasms?

Dual Channel TENS EMS Unit Physicians and physical therapists often recommend their patients use a TENS machine for muscle spasms.

Researchers have found that TENS can help ease muscle spasms caused by illnesses such as arthritis, back pain, knee pain, period pain, and sports injuries.

A study used the TENS unit for treating patients with muscle spasm after the lesion of upper motor neurons.

The study finds a statistically noteworthy shrinkage of muscle spasm in patients treated by TENS.

According to a review conducted by the Center for Psychiatric Rehabilitation, spasticity has behaved after spinal cord injury (SCI). The review refers to a study that used nerve stimulation in the leg which aids in a diminution in muscle spasms; however, it may need a further experiment. 

The cause of muscle spasms depends on your device, intensity level of your TENS machine & appropriate use of it. Hence you need to learn how to use the TENS machine.

Here are some articles on TENS usage for different parts of the body.

For the neck, read the article on how to use a TENS unit for neck pain.

For Shoulder, read the article on how to use a TENS unit for shoulder pain.


TENS may not be safe for everyone. So, please take advice from an expert physician if you have the following medical conditions:

  • if you have a pacemaker or metal implant in your body
  • if you're pregnant
  • if you have epilepsy or a heart problem

Avoid all these:

  • Avoid insertion of the electrodes on irritated or broken skin.
  • Avoid using TENS while you are asleep.
  • Avoid using the TENS machine while driving.
  • Avoid using high current while electrical signals are applied to the skin.

Don’t do these:

  • Do not place pads or electrodes over the eyes, head, spinal column, tumors & on the chest.
  • Do not put the electrode in place for a long time without cleaning.
  • Do not use the TENS unit while taking a shower.
  • Do not use it along with heating pads and ice pads.

Although using a TENS machine is considered to be safe & comfortable, you must be conscious of its incorrect & overuse.



  • What is the perfect wireless TENS device for me?

It depends on every person’s requirements. You can check the detail of a device to decide which one is perfect for you, or you can consult with an expert.

  • Can I move around easily while using wireless TENS?

Yes. You can move around easily at the time of using a TENS unit.

  • What is the duration of using a TENS Machine?
    • For severe ache- 20/60 minutes up to 4 times each day.
    • For chronic ache – 20/30 minutes up to 5 times weekly.
  • Can the TENS unit cause any damage to my body?

No. But you may feel skin irritation.

Concluding Remark:

Researchers have found that TENS machines have the proficiency of releasing pain, decreasing muscle spasms, swelling tissue oxygenation, and improving circulation. The arrival of wireless TENS machines adds a new dimension with all these advantages.

The extreme popularity, simplicity in usage & portability will encourage you to purchase a wireless TENS machine for comforting your painful life. To identify a perfect piece of a wireless TENS unit, you may take the assistance of our ultimate  buying guide on the best wireless TENS unit.

Skin irritation, muscle twitching & soreness are the common side effects of the TENS machine. These side effects can be reduced to a great extent by applying the device accurately.

In this discourse, we have tried to assist you in learning about the TENS machine side effects as well as adequate precautions before using the device. We strongly believe that this will be very supportive of you.

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