TENS units have increased dramatically in popularity over the years. At-home solutions to pain relief are becoming even more prevalent with the current state of the world and the COVID-19 pandemic. Many telemedicine doctors, chiropractors, and physical therapists are telling their patients to get a TENS unit to help them relieve pain at home without having to risk exposure coming into the office. 

With all of this buzz surrounding the TENS unit, very few people sit down to truly explain what a TENS unit is and how it works to relieve pain since they believe it to be common knowledge. 

Below is a discussion of what a TENS unit is, how it works, who can benefit from the device, the limitations, and the best way to get good results with the device. 

What is a TENS unit?

A TENS unit is a Transcutaneous Electrical Nerve Stimulation unit. This mouthful of a name attempts to describe the function of the device. In simpler terms, the TENS device is a nerve stimulating device that works along the surface of the skin. This stimulation is delivered through a pulsing of electricity across electrodes. 

A typical TENS unit contains a hub device, two electrical leads, and an adjustment dial to adjust the intensity of the stimulation. 

A less conventional but more portable TENS pen takes a different approach to what a TENS unit should look like. The Hempvana Rocket is a rocket ship-inspired, pen-sized TENS unit that can provide muscle stimulation in seconds. 

Where traditional TENS units need to strategically place leads to get the pain relief they need, The Hempvana Rocket provides targeted pain relief easily. Simply place the electrodes onto the site causing pain and watch as the electrical pulses go to work to temporarily melt away pain. 

How do TENS units work?

The TENS unit works by delivering electricity across the skin’s surface which stimulates the nerves for sensation and other nerves such as neuromuscular neurons. While this part of how a TENS unit seems simple enough, how does this stimulus result in pain relief? This question is actually not fully proven but there are two main theories as to why TENS unit therapy works to alleviate pain.

Gate Control Theory

The gate control theory is a theory utilized to explain the sensation of pain and the ways in which it is altered. In the theory, it is proposed that there is a figurative gate that allows the sending of pain signals to the brain. When other firing neurons outbid the number of pain signals being sent, the gate closes for the pain and opens for the other neuron. 

When applied to TENS therapy, this makes a lot of sense. When the TENS unit is being utilized it creates a sensation across the skin and around the point of contact. When using a TENS unit, pain may still be felt. When this occurs the user can increase the intensity of the unit which increases the frequency that electricity is sent across the skin. The more frequently the nerves are stimulated, the more signals are sent to the brain. This is the reasoning as to how changing intensity on the TENS unit impacts the physiology of pain perception. 

Release of Endorphins

Another theory is that the stimulation of nerves somehow releases the body’s natural pain killers and endorphins. This theory is popular because the pain relief for TENS unit therapy tends to linger well beyond when the TENS unit is turned off. 

Both explanations are generally accepted as to how the TENS unit functions within the body.

What kinds of pain can benefit from a TENS unit?

Many different forms of pain can be temporarily alleviated through the use of a TENS unit. This includes the following pains:

  • Back
  • Shoulder
  • Neck
  • Knee
  • Hip

The reason the TENS unit is effective for pain management for so many different kinds of pain is that it works by drowning out pain signals to the brain with a flood of other signals from the nerves stimulated through the TENS unit. 

Who shouldn’t use a TENS unit?

While a TENS unit seems like a fits-all solution for pain, it can be dangerous for some populations. These include the following:

  • Pacemaker – Those who have a pacemaker installed should avoid utilizing the TENS unit. The electrical pulse sent through the TENS machine could incidentally impact the ability of the pacemaker. If the rhythm is disrupted within the pacemaker it could quickly become a serious health concern. 
  • Spinal Cord Stimulator – A spinal cord stimulator is an implanted device that works similarly to the tens unit. It sends electrical pulses directly to the spinal cord to alleviate pain. A TENS unit should not be used alongside one of these devices because it could interfere with the embedded device or cause malfunction.  
  • Insulin Pumps – While TENS could generally be used with individuals with an insulin pump, it is probably wise to forgo this method of pain relief just in case. An insulin pump is responsible for properly administering a substance known as insulin. Insulin is the hormone that regulates blood sugar levels in the body. For those with diabetes, have a lack of insulin or lack of response to insulin and need supplemental insulin daily. Insulin pumps are designed to administer the precise amount of insulin necessary. Since a TENS unit utilizes electrical pulses, these could potentially interfere with the electronics in the pump and potentially cause an issue. 
  • Pregnant – Those that are pregnant can utilize TENS but it is advised to not place leads around a pregnant belly as it could impact the baby in some capacity. 
  • Organ Associated Pain – Those who are hoping to gain pain relief from organ associated pain should look for alternative options. TENS units are exclusively utilized on the surface of the skin and the leads themselves are nowhere near penetrating enough to assist with pain originating from deep within the body.
  • Metal Implants – Another group that should be cautious when utilizing a TENS unit are those with metal implants. While it is perfectly okay for an individual to utilize a TENS with metal internal hardware, they need to be careful to not place the TENS leads directly over or near the hardware. 

Where shouldn’t you use a TENS unit?

While the TENS unit is a great way to achieve pain relief, it has its limitations to where you can utilize it. Since the TENS unit utilizes electrical pulses to stimulate nerves, it can interfere with the normal functioning of important neurological components. Here are two main places to avoid when utilizing a TENS unit:

Head – The face is a highly compact region of muscles that allows us to display emotions, talk, and eat. Muscle tightness in the face is common and there are many solutions like massaging or vibration therapy that can help with stiff facial muscles. A TENS unit should not be used on the head or face because of its close proximity to the brain. 

Throat – The throat can also be a spot of tension but a TENS unit should not be utilized in this region. The throat is a critical airway that needs to stay open and free of spasms. The TENS machine typically causes muscle spasms and makes it not a very good fit as a treatment option. 

What can you do in addition to TENS unit treatment?

Whether you are looking to improve your pain management routine or are looking for TENS alternatives because you are ineligible; other pain management tools are out there and can also provide lasting relief. 

  • Compression: Compression is a great addition to a pain management routine. Compression works by putting pressure on the affected area for the purpose of promoting better circulation. After a TENS unit session, consider picking up a pair of compression socks to keep the relief going.  
  • Pain Relief Cream: Hempvana Pain Relief Cream is an amazing way to achieve targeted temporary pain relief while also treating your skin to hydration and protection. The ingredient Trolamine Salicylate acts to relieve pain while the hemp seed extract acts to provide lasting moisture. 

Both of the treatments can be done in addition to TENS unit stimulation. The best order to follow would be to perform the nerve stimulation, apply the pain relief cream, and finish off with putting on compression. This trifecta is a great method to give you the max benefit of each individual component. 


In summary, a TENS unit can be as little as a handheld device that stimulates nerves in the skin and muscle to help alleviate pain. Pain relief is achieved through this method by drowning out the pain nerve impulses with a flood of other impulses as well as releasing the body’s endorphins.