Are TENS Units Safe to Use?




Are TENS units Safe to Use?

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A TENS (Transcutaneous electrical nerve stimulation) unit is often given to patients by doctors or physical therapists to treat pain at home. You can also purchase them online on Amazon and other retailers, which means you can use them without the guidance of a medical professional.

So, are TENS units safe to use? Yes, they are safe to use with or without supervision. However, as with any medical device, there are side effects and risks if you don’t use the unit correctly. As long as you follow the directions and only use the machine as intended, it shouldn’t be dangerous.

Most side effects that users have are due to using the unit incorrectly. This article will take a look at how to use a TENS unit correctly, possible risks and side effects you may experience, and who should and shouldn’t use the device.

Understand Your TENS Unit

Before you use a TENS unit, you should have a thorough understanding of how it works and how it’s supposed to help you. The unit uses electrical currents to treat pain, which can cause some users to be wary of the treatment. Understanding the basic functions will help alleviate any worries you might have about the unit and the treatment.

Any questions or concerns you may have can be directed to a medical professional like a doctor or a physical therapist. They can also help you determine if this therapy is the right treatment for the type of pain you’re experiencing.

What Does a TENS Unit Do?

A TENS unit sends small electrical currents to your body to treat pain. The treatment doesn’t appear to be effective enough to make the pain go away completely, so it’s often used as a temporary pain reliever by doctors and physical therapists. It can relieve both chronic and acute pain.

The types of pain the TENS unit can relieve includes:

  • Joint
  • Neck and back
  • Menstrual
  • Post-operative
  • Labor
  • Arthritis
  • Fibromyalgia
  • Injuries
  • Multiple sclerosis

TENS units are available over the counter, no prescription needed. However, for more powerful machines that will have better results, you will need to talk to your doctor to receive a prescription.

Want to know where else a TENS unit can be placed?  Check out my TENS placement guide here

How Does It Work?

The TENS unit connects to your skin with sticky pads called electrodes. The electrodes are connected to the unit with wires. Electrical currents are delivered from the unit to your body through the electrodes.

The electrical current goes to your nervous system and prevents pain signals from being delivered to your brain. While using this treatment, you will still have pain, but you won’t feel it as bad, or maybe you won’t feel it at all, because your brain isn’t receiving any pain signals.

This treatment can also cause your body to release endorphins. Endorphins are hormones that are essentially natural pain killers. When endorphins are released, they also block pain signals from going to your brain. This can cause you to feel relaxed or happy when receiving treatment.

How Do You Use It?

A TENS unit is simple to use. Your doctor or physical therapist will apply the electrodes for you if your treatment is on-site, but you can easily do it at home by yourself.

If you can’t reach the area you need to place the electrodes, find someone to help you. You need to apply the electrodes to specific areas where the pain is located, so it is better to get help from someone than to have them misplaced.

To use a TENS unit:

  1. Clean and dry the skin where you will put the electrodes. You can use soap and water or rubbing alcohol to clean the skin. Be sure to allow the area to dry completely. You could get shocked if the electrodes come into contact with water.
  2. Apply conductive gel on the bottom of the electrodes. This will allow the electrical currents to conduct smoothly, resulting in more effective treatment. If you don’t have conductive gel, you can skip this step.
  3. Place the electrodes on your skin and apply adhesive. Some TENS units have electrodes that already have adhesive on them. If you have to apply the adhesive yourself, you can use medical tape or a sticky patch. Be sure the entire electrode is covered, so it doesn’t move around.
  4. Connect the wires to the electrodes. The wires should simply plug into the electrodes. Consult the TENS unit manual or a medical professional for directions if you have any questions.
  5. Turn on the unit and adjust the settings as needed. Your doctor will most likely give you their recommended settings that they think will work for you.

What Settings Should I Use?

Different TENS unit models might vary slightly, but they typically let you change the settings of intensity, pulse, and frequency.

High frequencies of 80 – 120 Hz are generally used for acute pain. Low frequencies of 1 – 20 Hz are better suited for chronic pain. 

You can change the intensity of the stimulation, as well. You shouldn’t feel any discomfort while using this device. You will feel a tingling sensation while the unit is on. If the tingling is uncomfortable, painful, or unpleasant, lower the intensity. If you can’t feel any tingling, you need to increase the intensity.

Wondering how high can you set a TENS Unit? Learn more here.

What About EMS?

If you’re looking into a TENS unit because you want to try the therapy, you may have heard about the EMS unit. EMS, or electrical muscle stimulation, is another type of e-stim that’s very similar to TENS. 

EMS focuses on muscle stimulation, while TENS focuses on the nerves. The electrical current in the EMS is a little stronger than what a TENS unit uses. These stronger currents cause the muscles to contract. The EMS user can increase their muscle strength if they contract (flex) their muscles while using the EMS unit.

Some machines provide both TENS and EMS therapy. Make sure you know which electrodes and settings to use for TENS therapy if you choose to buy a dual unit.

Get TENS and EMS all in one.

iReliev TENS Unit

This is the exact TENS unit that I use. It is perfect for alleviating many common types of pain. The iReliev is a great little device and has a lot going for it. It is under $80 and has several programs to choose from and is small enough to fit in your pocket.

You do not need to spend hundreds of dollars to get a quality TENS unit and iReliev gives you a ton of value for the price being paid. Best part is they are based in Dallas, Texas and have phenomenal customer service FREE shipping and delivery in less than 5 days.

Get yours today on the iReliev website by clicking here

Possible Risks

TENS units are safe to use and don’t require the supervision of a medical professional. However, there are some potential risks and side effects to take note of. Most side effects and injuries are a result of using the unit incorrectly, whether it’s the application of electrodes, the intensity of the currents, or the duration of a session. 

The risks and side effects typically don’t require medical care because they are minor. However, if you experience any major negative effects from the treatment or unit, seek medical attention. Consult a doctor to receive guidance on how to properly use the TENS unit or to adjust a previous recommendation.

Possible Dangers

Certain circumstances can make TENS therapy potentially harmful to the user. It’s important that you know what the dangers are so you can prevent a harmful situation. Electrical currents can be dangerous, even when they are small.

Getting Shocked

TENS units conduct electricity, so it’s possible to get shocked while using it; however, getting shocked is usually a result of using the unit incorrectly. Because the unit only handles a small amount of electricity, if you do get shocked, it should be small and shouldn’t be enough to cause significant pain or damage to your body. However, you should remain cautious and only use the device as instructed.

You might get shocked if any part of the unit gets wet while you’re using it. Do not submerge yourself in water or get the unit wet. A small splash might be enough to shock you.

Can you overuse a TENS Unit? Learn more here

You could also get shocked if you remove the electrodes while the unit is turned on. If you need to remove the electrode or reposition it during your treatment, turn off the unit before you do so.

If a wire is damaged on the machine and cords are exposed, you could get shocked if you touch them. Replace the wire if you’re able to do so or use electrical tape to cover up the broken portion. It’s always best to replace your TENS unit if it’s broken since it could cause you to get shocked.

TENS Electrode Pad Placement

Electrodes should be placed on or near the site of the pain. Avoid placing them directly over joints, as they are difficult to keep in place. They might fall off, and if you don’t have extra adhesive, you might not be able to use that electrode again.

Check out my comprehensive TENS placement guide here

Some electrode placements can cause more problems than annoyances, however. Electrodes should never be placed directly on the following areas:

  • Spine
  • Eyes
  • Head, neck, and face
  • Heart
  • Pacemaker or other implanted devices

Placing the electrodes directly on your spine could cause your blood pressure to become low. This is especially dangerous to those who have pre-existing issues with blood pressure or blood vessels.

Never place the electrodes on your eyes because pressure can build up and cause pain or injury.

For those with epilepsy, placing electrodes on your head, neck, or face can induce a seizure, especially if the epilepsy is uncontrolled. Even if you don’t have epilepsy, you should still avoid placing electrodes in these areas. They can cause a drop in blood pressure and can cause pain and injury.

The electrical currents can interfere with pacemakers and other devices, which can cause the devices to malfunction. This could cause your heart rate to become irregular and can be a great danger to your health. You should also avoid putting the electrodes over your heart for similar reasons.

Do not attempt to use electrodes internally. They are only to be placed outside of the body.

Sleeping or Driving

You should never use a TENS unit while you’re sleeping because you can’t monitor how you’re responding to the treatment. It’s possible for the current to be too strong or the frequency to be too high, which can result in your skin getting burned. If you’re asleep, the burn could get worse because you’re unable to remove the electrodes.

Since you must monitor yourself while using the machine, you shouldn’t use it while driving. You might have to adjust the settings or remove electrodes. This can be dangerous to do while driving since you’d have to take your eyes off of the road, so it’s best to wait until you can give the treatment your undivided attention.

Increased Tolerance

Some users who use a TENS unit frequently might find that they have built a tolerance to the treatment. Once you build a tolerance, the settings you typically use no longer feel effective, so you will want to increase the intensity so you can feel the tingling sensation once again.

Just because you can’t feel the tingling doesn’t mean it’s not working on your muscles. Muscle soreness is a side effect of using too strong of an intensity. Your muscles can twitch during the treatment and will feel sore afterward.

If you have decreased feeling in parts of your body, you shouldn’t place the electrodes in that area for similar reasons. You won’t be able to feel the tingling, so you might feel inclined to crank up the settings.

TENS Unit Side Effects

There are very few side effects from the TENS treatment, and they are usually caused by using the unit incorrectly. They shouldn’t be severe enough to warrant immediate medical attention, but you should talk to your doctor if you experience any pain or if the side effects stick around for a prolonged period of time.

Side effects you might experience are:

  • Allergic reaction: This is often caused by the adhesive on the electrodes. If you have an allergic reaction, hypoallergenic options are available. There are also electrodes that don’t have adhesive on them already, so you can choose which adhesive you use that you know will be safe for you.
  • Pain: You might feel pain if the intensity is too high. It could also cause your muscles to twitch. Turn down the intensity if this happens. While the unit is on, you should feel a tingling sensation. The tingling should be strong, but not uncomfortable.
  • Soreness: Using the unit for too long could result in muscle soreness. Using a frequency that’s too high can also leave you feeling sore. Don’t use the unit for prolonged periods of time, and be sure that you only feel tingling, not pain, when you’re using it.
  • Skin irritation: If the electrodes are on your skin for too long, your skin might get red, and you might feel a little pain. You can avoid this by regularly removing the electrodes, only using the machine for short periods of time, and alternating electrode placements each time you use the unit.

These side effects should stop once you turn off the unit and remove the electrodes. Allow your skin and muscles to rest between uses, so they don’t become more irritated. Speak with your doctor about the side effects if they happen frequently or become severe. They can help you find adhesive you can use and appropriate settings that won’t cause muscle soreness.

If you experience skin irritation and you need to use the unit frequently, try alternating where the electrodes are placed every time you use the device. This will prevent your skin and muscles from tiring out because they aren’t used repeatedly in the same areas. Overexposure can cause irritation, even if you aren’t allergic to the adhesive or use too high of an intensity.

TENS Unit Possible Benefits

There are many reasons people consider TENS therapy as an option for pain relief. It can be an inexpensive treatment for many. TENS units are noninvasive. They don’t require needles, so the therapy can be used by almost anyone. The therapy is common among those who prefer to avoid using drugs.

Affordable Treatment

TENS units are an affordable painkiller option. You can purchase a unit online without a prescription from a doctor or without breaking the bank. There are several models you can choose from. The more expensive options might work better than the budget-friendly options, but each one should be able to bring you some level of pain relief. Stronger, more effective units will require a prescription and will cost more, however.

As previously mentioned, some TENS units are dual machines, meaning they are also EMS units, which focus on muscle stimulation. These machines are also affordable, even though they offer two different types of therapies. If you need both nerve and muscle stimulation, this can be an inexpensive way to receive the treatment you need. 


Some units are small enough that you can carry them in your pocket. So, you can use the unit while you’re working or doing chores around the house. 

Remember that you shouldn’t sleep or drive while using the unit, so if your job or daily activities require driving or machine operation, you probably shouldn’t use it during those activities.

Pain Relief

Pain relief is the main reason why people try TENS therapy. Physical therapists, doctors, and chiropractors might recommend TENS therapy to patients who have frequent pain.

The type of pain relief seems to vary from person to person. Some people only experience pain relief while the unit is on and actively stimulating the nerves. Other users have reported that pain relief lasted even once the unit was turned off. 

In some cases, users might be able to reduce the amount of pain medication they take because TENS therapy reduces their pain. This can be greatly beneficial for users whose pain medications have several side effects.

Reduce Inflammation

Although it hasn’t been proven with certainty, there is evidence that TENS therapy can reduce inflammation. If you have both pain and inflammation, the therapy will be able to treat your pain and possibly reduce your inflammation, as well. However, you shouldn’t seek out TENS therapy for the sole purpose of reducing inflammation since it’s not yet proven to be effective.

Chronic Pain Management

More studies need to be conducted to determine if TENS therapy is truly an effective pain management option for chronic pain. However, one study has shown that it was effective for treating osteoarthritis in several participants.

Many people with chronic pain from fibromyalgia or arthritis may find TENS therapy to be a great way to get some relief from their pain. Since it can only be temporary relief, it might be most effective if it’s used when the pain is at its worst. 

You Are in Control

Many medications don’t allow you to control your treatment. Sometimes you aren’t able to simply stop taking a medication if you decide you don’t want to use it any longer. Other medications have side effects that you no longer want to deal with, but you have to ween yourself off of it, which could cause a new set of side effects.

TENS therapy doesn’t have this kind of issue. If you no longer want to use it, you can stop it anytime. During the treatment, if you are uncomfortable, you can adjust the settings, so the frequency isn’t as strong, or you can turn the unit off and adjust the electrodes.

TENS therapy allows you to choose a drug-free method of pain relief. Many people want to choose drug-free alternatives because they don’t like how medications can cause side effects that can’t be controlled. Choosing a natural method over drugs can be beneficial to your health and overall well-being.

Positive Effects on Your Nervous System

TENS therapy stimulates the nervous system and prevents pain signals from going to your brain. Some chiropractors believe that continual treatment can train the nerves to stop sending pain signals to your brain. There isn’t much information to back this claim up, but if true, it means that TENS therapy can be a life-changing rehabilitation method after a serious injury.

Who Shouldn’t Use a TENS Unit?

TENS units aren’t recommended for everyone. Here are a few groups of people that shouldn’t use a TENS unit without consulting a doctor first.

Pregnant Women

The long-term effects of electrical currents on unborn babies are not yet known. Some sources will say pregnant women should not use TENS units at all. Other sources will say that women shouldn’t use them around their abdomen or pelvis. 

TENS units are sometimes used during labor to alleviate pain. This is okay because the baby isn’t exposed to the electrical currents for long, and the woman is being monitored closely by the doctor.

If you’re pregnant and want to use a TENS unit to treat pain, you should speak with your doctor before you purchase a unit. They will be able to help you determine if it is safe or not, and where to place the electrodes if they say it will be safe for you.

Medical Conditions

If you have a medical condition such as pre-existing lymphedema, psoriasis, or eczema, TENS therapy could make your conditions worse.

Lymphedema is swelling in the arms and legs due to poor drainage of fluids. TENS therapy affects the circulatory system and might cause more fluid retention and cause the lymphedema to worsen.

The adhesive on the electrodes or the electrical currents could irritate skin conditions like psoriasis or eczema. Speak to a doctor before you use a TENS unit so they can give you direction on how to use a unit in a way that won’t make your condition worse.


TENS therapy is safe for children to use, but should only be used if prescribed by their doctor. There are units especially made for children. These units shouldn’t be used by adults, so if you shop online for a TENS unit for an adult to use, do not buy a children’s TENS unit.

Much like adults, children with the previously mentioned conditions or implants shouldn’t use a TENS unit at all. 

Children may be more sensitive to the treatment, so you should only use the normal mode on the unit. Use the frequency that your child’s doctor recommends. Be sure to monitor your child the entire time and turn down the frequency if they complain about being uncomfortable.

Medical Implants

Those with medical implants should not use TENS units because the electrical currents can cause the devices to malfunction. If you have a pacemaker, this could result in your heart beating irregularly, which could potentially be lethal to your health.

You shouldn’t use TENS units if you have other implants such as wires, screws, or metal plates. The metal can interfere with the electrical currents, which is quite dangerous. 


If you have any concerns or questions about using a TENS unit, consult a medical professional such as your doctor or a physical therapist before you use one on your own. You should be able to find a physical therapist, doctor, or chiropractor in your area that offers TENS therapy sessions. So, if you’re uncomfortable using a unit yourself, you can pay for a session that is monitored by a professional.

Remember to contact a pediatrician if you’re interested in using this therapy to treat your child. While the machines are safe to use at home, children often require extra medical care and supervision. 


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One response to “Are TENS Units Safe to Use?”

  1. […] You can adjust the intensity of the current by pressing the minus sign on the TENS unit. You can safely use a tens unit for 20-30 mins 3 times per […]

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