Chronic pain disorders are a global health challenge impacting hundreds of millions of individuals, often diminishing their overall well-being and interfering with their daily routines. While looking for safer non-invasive pain relief therapies, people are turning away from medications due to the risk of opioid addiction- TENS or Transcutaneous Electrical Nerve Stimulation resolves this most conveniently.
Whether someone experiences back pain, arthritis, fibromyalgia, or post-surgical pain, TENS therapy can help reduce pain both in clinical settings and at home, and most importantly, without using medication.
But how effective is it? What is TENS? How does it work? In this comprehensive guide, we answer these questions by discussing the science of TENS, its pros and cons, and the most recent studies conducted on its effectiveness for various conditions. In addition, we will provide safety measures, proper usage instructions for the TENS unit, and determine whether or not this therapy would be compatible with your pain management plan.
Let’s explore the beat of this advanced method of pain relief.
What Is TENS Therapy?
Transcutaneous electrical nerve stimulation (TENS) therapy is a form of treatment that is non-invasive, with electrical currents set at low voltages being passed through the skin via electrodes to the peripheral nerves. This form of therapy seeks to manage pain and in some cases, alter the neural mechanisms responsible for processing pain signals.
TENS units are small and portable devices that allow users to personalize their pulse settings – frequency, amplitude, and duration.
There are common stimulation modes:
- Conventional TENS employs high-frequency, low-intensity stimulation, usually over 50 Hz. It produces strong but comfortable sensations without muscle contractions.
- Hold to 10 Hz low-frequency higher intensity (acupuncture-like TENS), seeks to produce muscle contractions.
- Mixed-frequency modes combine these to reduce tolerance over repeated use.
How Does TENS Work?
TENS therapy works primarily through two physiological mechanisms. The first is the “Gate Control Theory of Pain,” which claims stimulating larger nerve fibers (Aβ fibers) with electrical pulses eases pain during surgical procedures by closing–“locking” the spinal gate to smaller peripheral nerve fibers that carry pain messages.
The second is the electrical stimulation of the body’s opioid system, effectively asking the body to release natural pain suppressors such as endorphins and enkephalins. These substances acting at the level of the central nervous system blunt pain and provide relief.
These mechanisms explain the ability of TENS to deliver swift and effective non-drug pain relief for various conditions. [1]
Conditions Treated with TENS
TENS has been used for acute and chronic pain conditions, including:
- Musculoskeletal pain: back pain, neck pain, osteoarthritis, tendinitis, bursitis. [2]
- Fibromyalgia: TENS is widely used as a low-cost, safe, self-administered option, though evidence remains uncertain. [8]
- Labor pain/dysmenorrhea: some trials suggest benefit in relieving labor and period pain and delaying analgesia requests. [2]
- Diabetic neuropathy and phantom limb pain: tentative or limited evidence in neuropathic pain. [1]
- Knee osteoarthritis: recent trials found TENS effective and safer compared to weak opioids. [6]
- Xerostomia (dry mouth): TENS showed objective increases in salivary flow as a promising non‑invasive approach. [4]
Evidence and Research
The evidence for TENS therapy is a combination of positive results alongside some gaps in the research. As highlighted in the 2019 Cochrane Review, while TENS seems beneficial for pain control, particularly in the short term, its effectiveness tends to be overshadowed by poor-quality evidence due to shortcomings in study designs.
In 2022, BMJ Open published a study that noted moderate-certainty evidence supporting TENS for pain reduction during or post-use, reporting no serious adverse effects.
From a safety perspective, TENS is generally acknowledged as having very low risk, with the only documented risk being mild skin irritation. There are still unresolved issues, particularly with chronic low-back pain and neuropathic disorders where changes in function are minimal.
More recent studies have started to focus on the use of TENS alongside other treatments such as physical therapy and exercise due to their potential for improving outcomes, particularly early-stage knee pain.
Recent Advances
Studies incorporating TENS into exercise for early-stage knee osteoarthritis have demonstrated quicker achievement of pain relief milestones and improvement in overall outcomes. As noted in [6][7], TENS has high safety ratings, potential for significant reduction in opioid use, and a low risk of infection.
Strengths And Weaknesses
Employing TENS therapy has numerous benefits for pain management. For one, TENS therapy does not require surgery or medication, which makes it especially attractive to those who want to avoid medications due to side effects. Also, TENS units are convenient self-treatment devices that can be used in the clinic or at home.
In addition, TENS therapy might help curb reliance on opioids, which is a helpful alternative in these times of opioid dependency. Nevertheless, TENS units have their downsides. The effectiveness of TENS therapy is known to differ greatly based on the condition being treated, device settings, and the patient. Some patients may develop a tolerance to its analgesic effects over time through use, so continuously changing settings may be the only way to maintain effectiveness.
Moreover, TENS is not appropriate for everyone. It cannot be used by patients with pacemakers, certain medical conditions, or during pregnancy in some regions. In general, the therapy is quite safe; however, like all treatments, it should be administered with a physician’s guidance to harness maximum benefits and minimize complications.
Practical Use: How to Use a TENS Unit
- Consult your healthcare provider to confirm suitability and technique. [2]
- Place electrodes around or near the painful area, along nerve pathways.
- Adjust settings:
* Intensity: strong but comfortable tingling.
* Frequency/mode: high frequency for sensory relief, low for more prolonged effect. - Session duration: often 20–60 minutes; can be repeated multiple times daily, monitoring skin response. [2]
- Monitor skin for irritation; discontinue if rash, dizziness, headache, or nausea occur. [2]
- Manage tolerance by varying settings and session timing. [1]
Use in Specific Scenarios
- Osteoarthritis (e.g., knee): effective alternative to opioids; safe and useful for pain control, especially in elderly patients sensitive to medications. [6][7]
- Fibromyalgia: used commonly although evidence remains limited; part of multimodal therapy. [8]
- Labor pain: offers a drug-free adjunct; may delay need for epidurals and is portable for mobility during childbirth. [2]
- Dry mouth (xerostomia): emerging use to stimulate salivation. [4]
Key Takeaway
TENS therapy is a safe, non‑invasive, and user‑controllable method to manage various types of pain. It likely works via dual mechanisms, gate control modulation and endogenous opioid release. The evidence base supports its immediate pain-relief potential with moderate certainty, though long-term benefits and functional outcomes show mixed evidence across conditions.
Settings must be individualized, and clinical guidance is essential to avoid contraindications. Emerging research confirms TENS’s value in combination therapies, and popularity remains high due to accessibility and lack of systemic risks.
That said, further large-scale, high-quality randomized controlled trials remain necessary to clarify its efficacy across specific conditions.
References:
- StatPearls: Transcutaneous electrical nerve stimulation (https://www.ncbi.nlm.nih.gov/books/NBK537188/)
- Cleveland Clinic overview (https://my.clevelandclinic.org/health/treatments/15840-transcutaneous-electrical-nerve-stimulation-tens)
- BMJ Open (2022) study (https://bmjopen.bmj.com/content/12/2/e051073)
- MDPI clinical study on xerostomia (https://www.mdpi.com/2076-3417/15/5/2723)
- Springer article on CLBP (https://link.springer.com/article/10.1007/s10926-023-10121-7)
- ScienceDirect knee pain trial (https://www.sciencedirect.com/science/article/pii/S0003999324012267)
- Review on safety and opioids (https://www.tandfonline.com/doi/full/10.1080/09638288.2025.2453640)
- Wikipedia entries on TENS and Fibromyalgia (https://en.wikipedia.org/wiki/Transcutaneous_electrical_nerve_stimulation)