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Frequently Asked Questions — FAQ's About TENS Units & Muscle Stimulators

Your Complete FAQ Guide to TENS Units & Muscle Stimulation also known as Electrotherapy

Whether you're new to TENS and EMS or just looking to get the most out of your device, we’ve got you covered. Explore answers to the most common questions about how TENS (Transcutaneous Electrical Nerve Stimulation) and EMS (Electrical Muscle Stimulation) work, when to use them, and how to do it safely and effectively.

You’ll also find helpful tips, best practices, and device-specific guidance—plus everything you need to know about electrode pad care, placement, and maximizing results with your iReliev system.

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What is a TENS Unit?

A TENS unit, is a safe and effective device designed to deliver transcutaneous electrical nerve stimulation, a pain relief treatment that uses low voltage electric current to relieve pain.


TENS current delivers gentle electrical impulses to electrode pads that are placed directly on your skin that travel to the nerves. When TENS stimulates the sensory nerve endings, it blocks the pain signal from traveling to the brain. This creates a pleasantly relieving, tingling sensation in the place of pain.

The current that a TENS treatment sends can also produce endorphins.


TENS therapy is often used to manage pain while the body is healing in situations like post-surgery recovery, athletic or other types of injuries, and chronic pain like arthritis or acute pain.

What Does the ems mode do is it a massage function?

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What does TENS Stand For?

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What is the difference between TENS and EMS?

TENS targets nerve endings to help block pain signals and release endorphins. EMS targets muscle fibers, causing them to contract and relax to help with strengthening, rehab, and recovery.

What conditions can TENS help with?

TENS is commonly used for chronic pain, arthritis, sciatica, lower back pain, neck and shoulder tension, and post-surgical discomfort. Always consult with a healthcare provider for serious or persistent conditions.

Is electrotherapy safe?

Yes—when used as directed. Always read the user manual, avoid placing electrodes over the heart, throat, or broken skin, and consult your doctor if you have a pacemaker, epilepsy, or other health concerns.

How often can I use my TENS or EMS device?

You can safely use TENS and EMS daily. Most sessions range from 15 to 30 minutes, and you should give muscles time to rest between EMS sessions, especially during strength training protocols.

Where should I place the electrodes?

Follow the electrode placement guide included with your device or visit our ProTips section for step-by-step videos. Placement varies depending on the area you're treating and whether you're using TENS or EMS.

Does TENS or EMS hurt?

No. You may feel a tingling, pulsing, or tapping sensation. It should never be painful—just adjust the intensity to a comfortable level.

Can I travel with my device?

Absolutely. TENS and EMS devices are compact, portable, and TSA-friendly. Be sure to pack electrode pads in a resealable bag, and carry your user manual for easy reference.

Can I use iReliev TENS Unit if I have a pacemaker?

No, you should not use a TENS unit if you have a pacemaker—unless approved by your physician.

Why?


TENS units send electrical impulses through the body, which may interfere with the electrical signals of your pacemaker. This can be dangerous and lead to serious complications.

Where is the serial number on my TENS Unit?

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What type of batteries are used in TENS Units?

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Will sweat prevent electrode pads from adhering?

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Can I Use iReliev in Conjunction With Topical Pain Rubs or Gels?

What Does the EMS Mode Do? Is It a Massage Function?

Why Won’t the Intensity Increase?

Do iReliev Electrode Pads Made With Gel Contain Salicylate?

Is It Necessary to Use an Electrode Gel With This Device?

Can the Intensity Selections Be Manually Adjusted During the Sessions or Do You Have to Reset It to Get It Just Right?

How Do I Remove Electrode Pads From the Skin?

What to Do if Lead Wires Are Faulty?

How Does iReliev TENS Help Reduce Pain?

Is This Product FSA/HSA Eligible?

What to Do if Pads Are Too Sticky?

Can I Use iReliev While Pregnant?

Is the Unit Health Canada Approved for TENS and EMS or Just TENS?

How Long Can iReliev TENS and/or EMS Be Used in a Day?

What’s the Difference Between the 1313 Model and the 7070 Model?

How Long Do the Wireless Pads Last?

Do iReliev Electrode Pads Contain Latex?

How Many Times Can Electrode Pads Be Used?

Where are your TENS Unit Set Up Videos?

Check out our libarary of How to set up your TENS Unit Videos on YouTube