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

Jump to a Section:

• Introduction
• What is TENS therapy?
• What to look for in a TENS machine
• Comparing TENS units
• TENS unit quiz (+20% off)
• Conclusion

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.

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:

• Back pain
• Neck pain
• Joint pain
• Arthritis
• Fibromyalgia
• Cancer pain
• And more

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.

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.

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 (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

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.

When it comes to size, you have a few options. The industry standard is 2"x2". However, there are a few sizes/shapes, including 2"x4" and round 3". This is entirely up to the user's preference. However, larger pads will cover a more significant surface area.

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.

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.

Channels

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.

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). 

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.

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.

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.

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.

Portability

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. 

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.

TENS + EMS

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.

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.

Brand

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.

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.

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.

Conclusion

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.

Helpful Pain Management Resources

The Ultimate Guide to TENS Units

Product Quiz: Selecting the Right TENS Unit

The Ultimate guide to Pain Management

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.