TENS Unit Buyer’s Guide: How to Choose a TENS Machine

Trying to decide on what TENS machine to buy?

We've got your back.

This article breaks down the key factors to consider before purchasing, including intensity levels, customizable settings, trustworthiness, and more.

Continue reading to find the ideal TENS unit based on your needs!


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If you’ve found yourself in pain and in search of drug-free methods of escaping it, chances are you’ve come across the miracle machines that are TENS units. These devices offer a safe, effective, drug-free alternative to prescription pain medications. While how these devices work is simple, selecting the right one can be complex if you’re new to this type of therapy.

Not only that but not every machine is the same. Depending on the brand, each device is built with different quality, features, uses, and more. Some promise TENS therapy but only deliver a massage-like sensation. In this guide, we’ll direct you through the essentials of TENS units, including what they are, how they work, and critical aspects to consider when buying.

What is TENS Therapy?

TENS (transcutaneous electrical nerve stimulation) therapy is a drug-free method of pain relief. This method of pain management uses a small device called a TENS unit which delivers mild electric shocks to the target area through electrodes. TENS units achieve pain relief in two ways: endorphin release and pain gaiting.

When a TENS unit stimulates nerves, it causes the body to activate and release endorphins. When endorphins are released, they reduce pain and make us feel happier. This is commonly achieved with pain medication. However, TENS units accomplish the same effect without the risk of addiction or dependence.

Have you ever started rubbing an area in pain? This is your body's way of pain gaiting. The sensation of pain works in the following ways:

  • An impact happens to cause physical pain (a bump, scratch, etc.).
  • The body’s small nerve fibers in the body part send sensory signals to the spinal cord.
  • Those signals are then sent to the brain to perceive the pain, and pain is felt.
What is TENS Therapy?

Pain gating, also known as gate control theory, prevents pain from being felt by blocking pain signals from reaching the brain. This is achieved by some sensation method, such as rubbing or massaging. TENS units perform pain gating by activating the large nerve fibers through a tingling or massaging sensation. This blocks the pain and minimizes the brain’s perception of the pain.

TENS units are excellent for pain relief, not only because of their safety and effectiveness but because of how universal and targeted they are for pain management. TENS devices effectively eliminate pain for a large variety of conditions, including:

Users can place the electrodes over the area in pain, select their treatment settings, and continuously use their TENS device whenever needed. If you’re interested in learning more about how these devices work, we recommend reading our Ultimate Guide to TENS Units. In it, we go further in-depth into how TENS therapy works, what it treats, and more.

What to Look for in a TENS Machine

No TENS unit is the same. While they may look, feel, and act the same, differences may make or break their effectiveness. Not only that, but the suitable TENS machine will need to meet your needs depending on your pain type, level, and specific features you need. This section will cover key features to look for before buying.

Acute or Chronic Pain for TENS therapy

Your condition (acute/chronic)

Your condition is the first thing to consider as it is going to overhaul any other factor to consider. Acute pain occurs quickly and goes away when the cause has eased up. Chronic pain is a more severe and intense form of pain that lasts longer than six months. Unlike acute pain, it continues when the condition has been treated.

With acute pain, almost any genuine TENS unit will suffice. However, a decent quality TENS unit that delivers a moderate-high intensity is essential with chronic pain. Chronic pain will require more TENS sessions, given it lasts longer. This requires a device that can provide consistent pain relief for numerous sessions.

Target Area for TENS Therapy

Your target area

Most TENS units are full-body TENS machines for universal treatment on any (safe to use) area. However, there are a few which target specific areas. Some are foot electrotherapy machines (foot TENS units), while others are for the lower back. If you only need to target a particular body part, this might be worth considering. However, these specialized devices limit where you can target.

Another aspect to consider is the target area’s size. Larger areas, to be entirely targeted at once, will need to have the capacity to use more electrodes at once. We’ll go further into this feature in the “channels” section.

Lifestyle for TENS therapy

Lifestyle (on the go, in an office, etc.)

Where will you primarily be using your TENS device?

If you’re on the go often, then a compact unit (and even with a belt clip) that offers portable electrotherapy might be ideal. Additionally, you’ll want one that comes with a carrying case for easy storage. If your sessions are primarily at home, these features may not matter as much.


Electrodes (stickiness, wired/wireless)

Electrodes also called TENS pads, are essential to factor in. How sticky are the electrodes, and how long do they last? Pads that aren’t sticky will struggle to adhere to the target area and be a hassle during sessions.

Types of TENS Unit Pads: Pig-tail and Snap-on

A key question frequently asked is, "are TENS pads universal?" While most TENS units use the same fitting, some are not. This depends on the manufacturer/brand. However, there are two standard types of TENS pads: pig-tail and snap-on.

Pig-tail style pads feature a slim end piece attachment. Their matching lead wires have a small piece of metal that slips right into the connecting element. Snap-on electrodes feature a button-style connecting portion that you press together to attach.

Sizes of TENS Unit Pads: 2" x 2", 2"x 4", and Round 3"

When it comes to size, you have a few options:

  • 2" x 2" - These are the industry standard and are what most devices come with. They're great for universal treatment but may not be ideal for larger target areas.
  • 2" x 4" - These rectangular shaped pads are ideal for larger target areas. However, they are not ideal to target joints as their larger size tends to cause them to bunch up or lift from the skin.
  • 3" Round - These are the smallest type of electrode. They're great for targeting smaller areas such as joints, fingers, and toes. Their shape and size keeps them pressed even when used over joints.

The electrode type chosen is entirely up to preference. Before deciding, consider the area you'll be primarily targeting and its size.

Wired vs. Wireless

Some TENS units feature wireless TENS pads. These are convenient as they eliminate the risk of becoming tangled and are less noticeable (great for public use). However, these can be more expensive and heavier than traditional pads.

TENS Unit Garments: A Great Alternative

Another option to consider is TENS unit garments. These specially lined gloves, knee sleeves, and socks connect to lead wires. They typically require being wetted to transfer the electric current. They can be a great alternative to traditional electrodes as they don't have a stickiness to lose. However, they need to be wetted, which may not be convenient when on the go.

Do I need gel for a TENS unit?

No, most devices use pre-gelled electrodes. However, you can purchase additional gel to apply, which will extend the life of the pads.

TENS Unit Channels - Single Channel: one lead wire and can run two electrodes at once - Dual: two lead wires and can run four electrodes at once. - Quad: four lead wires can run eight electrodes at once.


A TENS unit’s channels refer to the number of lead wires that can be plugged in simultaneously. More lead wires equate to more TENS pads to target a larger surface area at once. Most TENS units feature single, dual, or quad channels.

  • Single: Has one lead wire and can run two electrodes at once.
  • Dual: Has two lead wires and can run four electrodes at once.
  • Quad: Has four lead wires can run eight electrodes at once.

Most TENS units feature dual channels, which suffice for most users.

TENS Unit Pulse Duration

Pulse duration

The TENS unit’s pulse duration is the length of the pulse it administers. Longer durations allow the device to stimulate longer. Standard TENS units feature an adjustable range for customizability. Pulse duration is measured in microseconds uS (1,000th of a second). 

TENS Unit Pulse Rate

Pulse rate

The unit’s pulse rate refers to the number of electrical pulses felt in one second. The frequency is measured in Hertz (Hz). Pain relief can be achieved at various frequencies, making this feature important. For acute pain, the most effective range lies between 80 and 120 Hz. Meanwhile, a high-frequency TENS setting of 2 to 10 Hz is best for chronic pain to stimulate endorphin release. A range of 25-50 Hz is best for muscle stimulation.

Pain TypeBest Pulse Rate
Acute80-120 Hz
Chronic2-10 Hz
Muscle Stimulation25-50 Hz
TENS Unit Timer


Most TENS units feature a preset timer that shuts off the device after a specific period. This can add convenience or place limitations on sessions. Some feature a flexible timer or auto-shutoff, requiring you to restart the machine for extended treatments.

TENS Unit Intensity Levels

Intensity level

A device's intensity level delegates how powerful the treatment is. A higher intensity level from a professional grade TENS unit delivers a more robust electrical current to the target area. Intensity levels are measured in microamperes (mA). Most TENS units provide up to 80 mA, which is more than enough for most users. Some units deliver up to 100 mA, but most are prescription units. The more severe the pain, the stronger the intensity needed to block it.

TENS Unit Modes


Most TENS devices come with a set of predefined modes. These can make getting started easier as they have a set pulse duration, pulse rate, timer, and intensity. More expensive devices typically have more modes and let you select various modes for each channel. However, this may not matter if you’d prefer to customize your TENS unit settings.

TENS Unit Portability - Belt Clip and Size


As mentioned earlier, your lifestyle may dictate which device is your best bet. TENS units come in all shapes and sizes and sometimes feature belt clips for hands-free use. Ask yourself, “how often will I be using my TENS unit outside of my home?” If your answer is often, then you’ll want a portable device. 

TENS Unit Accessories


The suitable TENS unit accessories can add a lot of value to your purchase. Some TENS unit kits include a:

  • Carrying case
  • Additional electrodes
  • Lead wires
  • And more.

While this can bump the price up, it can be well worth the added bang for your buck.


More advanced units feature TENS and EMS settings and capabilities. These capabilities allow them to relieve pain and strengthen muscles. A combination unit is an excellent feature if you’re looking to build and tone muscles and ease the pain. However, if pain relief is your only mission, a standard more easy-to-use TENS unit will suffice.

Uses low-frequency electrical impulses to stimulate sensory nerves and reduce pain
- Can be used for chronic or acute pain management, including back pain, arthritis, and menstrual cramps
- Does not cause muscle contractions
- Can be used by anyone seeking pain relief, including athletes, pregnant women, and individuals with chronic pain conditions
- Uses higher-frequency electrical impulses to stimulate motor nerves and cause muscle contractions
- Can be used for muscle strengthening and rehabilitation, including after injury or surgery
- Does not provide pain relief directly, but can indirectly by reducing muscle tension and increasing blood flow to the affected area
TENS Unit Battery Type

Battery type (pros and cons of each)

The type of batteries these devices use varies. Some use rechargeable lithium batteries, meanwhile single-use batteries like AAA or 9V power more traditional units. Rechargeable batteries can save you time and money in the long run, while non-rechargeable batteries quickly swap out without having to wait for charging.

Rechargeable BatteriesSingle Use Batteries
- Less expensive for those using their device frequently
- Convenient, never have to be replaced
- Environmentally friendly
- Easy to use and charge with a simple charging port
- The longer battery life ensures you don't have to worry about frequently recharging your device
- Non-rechargeable batteries can be easily replaced with new ones
- Non-rechargeable batteries are more portable and convenient for on-the-go use
- Non-rechargeable devices have a lower up-front cost
- Need to be recharged frequently
- If the battery fails, the entire device may need to be replaced (if it's built in)
- Will be more expensive in the long-run as batteries need to be replaced
- Have a more significant impact on the environment as they contribute to waste and pollution
- If you run out of batteries, finding replacements can be challenging if you don't have them on hand
- Risk of leakage: Non-rechargeable batteries can leak over time and damage the device if they are not removed promptly.
TENS Unit Brands


Reliable TENS brands have been making TENS devices for years; meanwhile, others are relatively new. Established brands are typically more trustworthy, make proper TENS devices, and don’t just massage your target area. It’s also important to look into the price of their electrodes and if they’re compatible with pads that aren’t their brand. You don’t want to get stuck with a brand whose pads are expensive or not compatible with off-brand electrodes.

Reviews from customers

As with any purchase, you’ll want to look at the reviews. Look for in-depth reviews where users express their:

  • Experience with the device
  • Its features
  • And even the type of pain they’re treating. 

Paying attention to the last can give you a good idea of the device’s capabilities for treating specific pain types.

Reviews from experts (physical therapists, chiropractors)

TENS units are a ubiquitous device that professional physical therapists and chiropractors use. If you find a device you like, research what experts say about it. Their recommendations can provide more comfort with your decision as they are familiar with these devices. Many chiropractor TENS machines are readily available for purchase without a prescription.

Over the Counter vs Prescription TENS Units Comparison

Prescription or over the counter?

Does a TENS unit require a prescription?

Did you know TENS units were initially available only with a prescription? However, they’ve become more readily available over the counter over the years. Prescription-strength TENS units typically feature a higher intensity setting (often up to 100 mA) and have more treatment modes but are often more expensive. Over-the-counter units are usually more compact and not as robust. It’s best to talk to your doctor to see if a prescription TENS unit is necessary.

FSA/HSA Approved

Insurance Eligibility

One of the many perks of using TENS therapy is the devices are often eligible to be covered by insurance policies, making them ideal for those on a tight budget. This might be worth considering when choosing a machine, as it can save money. There are a few things that may make a device eligible, including:

  • Medical necessity: The device must be prescribed as a medical necessity by a professional for a specific condition.
  • FDA approval: The device must be FDA-approved for the particular condition being treated.
  • Cost: The cost of the device must be reasonable and necessary for treatment
  • Coverage policy: Your policy must cover TENS units or other durable medical equipment.
  • Documentation: A healthcare provider must provide documentation of the medical necessity of the device and any other documentation required by the insurance company.

If getting insurance to cover your device is essential, check the TENS unit's eligibility with your insurance company before purchasing.

For more detailed instructions, read our guide on getting your device covered by insurance.

Are you on an FSA/HSA account? Shop our full line-up of devices that have been approved for FSA/HSA reimbursement.

Product Warranty


Purchasing a device with a good warranty can be great should it malfunction. It’s the nature of electronics sometimes to underperform or have issues. This makes having a decent warranty an excellent idea to have the device replaced should anything happen to it.

Comparing TENS Units

Below, you'll find our comparison chart of all the current TENS devices we currently carry. We've included all the essentials, including the size, intensity levels, modes, and more, to help guide you in the right direction.

TENS Unit Quiz

Take our TENS unit quiz to get the best recommendation based on your needs.

Frequently Asked Questions

What is a True TENS Unit?

As the popularity of TENS units continues to grow, it's essential to understand what a genuine TENS unit is. Many devices on the market are labeled as true TENS but only deliver a massage-like sensation. These devices should be avoided.

A proper TENS device relieves pain through electrical impulses delivered via electrodes placed on the skin. These devices have multiple settings for intensity, frequency, and pulse duration. They feature different modes of stimulation for specific pain types.

Before purchasing any TENS device, look at the reviews for feedback. Reviews will show you if it delivers true TENS and effective pain relief. It can also be helpful to look for medical expert reviews. If you're in doubt, consult your doctor to see if they recommend the specific device you're interested in.

How Much Does a Medical TENS Unit Cost?

As the popularity and availability of TENS units have grown, their cost has gone down. The most powerful TENS devices can be affordable in the $30 to $100 range. For prescription devices, these can be upwards of $500. The price will vary depending on features such as multiple channels, programmable settings, and wireless connectivity.

Insurance coverage eligibility is essential to know when looking for a device. Some insurance plans will cover the cost of a device that a healthcare provider prescribes as part of a treatment plan. For more information, we recommend reading our guide, "How to Get a TENS Unit Covered by Insurance."

How Often Should a TENS Unit be Replaced?

The lifespan of a TENS unit can vary depending on the brand and model, as well as how frequently it is used and how well it is maintained. Generally, a well-maintained TENS unit can last for several years before needing to be replaced.

However, the lifespan of electrodes used with a TENS unit is limited. These will need to be replaced more frequently than the device itself. Electrode replacement frequency will depend on a few factors, including the brand, how often they're used, how well they're cared for, and if the skin is adequately washed before use. Electrodes can last anywhere between two to four weeks with regular use.

If you notice signs of wear and tear on your device or it's no longer effective, it might be time for a replacement. You may also want to check with the manufacturer's warranty to see if it can be replaced for free. Many brands offer warranties that will replace the device should it malfunction within a given period.


TENS therapy offers an affordable solution to pain management, allowing you to go about your daily activities pain-free without the use of addictive medications. When selecting the correct TENS unit, be sure to keep the features we’ve highlighted in mind to ensure you make the right choice. The ideal TENS unit will meet your lifestyle needs, deliver an adequate intensity level, and allow you to target your area(s) in pain.

About the Author

Brandon Landgraf is the Digital Marketing Manager for Carex Health Brands. He finds passion and fulfillment in creating content that enhances, improves, and enlivens others' quality of life. All of his written work is formulated to not only offer essential advice and tips but back it with proven studies and experts. His mission is to connect with readers and provide steps to make their lives better.

You can connect with him on LinkedIn here.

About Carex Health Brands

Carex is your one-stop shop for home medical equipment and for products that assist caregivers with providing the best possible support and care for their loved ones. Carex Health Brands has been the branded leader in in-home, self-care medical products for over 35 years. Our goal is to improve the lives of our customers by bring them quality products that bring dignity back to their lives. With our three nationally distributed brands, Carex Health Brands serves national, regional and independent food, drug and mass retailers along with wholesalers, distributors and medical dealers.


  • Felipa VaughanFeb 10, 2023

    Hello carex.com owner, Your posts are always well-received and appreciated.

  • Margaret Sheridan Apr 17, 2023

    I have severe scoliosis with pain in &around left hip,I have used a small (two wire, 3 A battery) Tens machine that pulsed & massaged that seemed to temporarily help the pain. It had stick on pads & easy to use. That’s what I’d be interested in.

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