If you are weighing photobiomodulation for neck pain, the honest first question is whether the clinical evidence actually holds up, and for neck pain specifically, the trial record is one of the more developed in musculoskeletal light therapy. A meta-analysis published in The Lancet, a 2025 network meta-analysis comparing six physical-therapy modalities head-to-head, condition-specific systematic reviews, and individual RCTs run across more than a dozen countries together form a multi-level evidence base. This article works through that evidence from the highest-level reviews down to the landmark individual trials, including where it is strong and where it is still thin.
For an overview of the complete neck pain evidence base, see Red Light Therapy for Neck Pain: Scientific Research Review. For the biology behind these outcomes, see Red Light Benefits for Neck Pain and Infrared Light Benefits for Neck Pain.
Key Takeaways
- Lancet-published meta-analysis: 16 RCTs, 820 participants, with pain reduction in chronic neck pain lasting up to 22 weeks after treatment ended. The acute-pain result was later shown to be statistically fragile (see below); the chronic-pain result held up.
- Network meta-analysis ranks laser therapy at the top: A 2025 study comparing six biophysical agents head-to-head ranked high-intensity laser therapy first for neck pain. Low-level laser therapy ranked fifth of six but still outperformed placebo.
- Condition-specific meta-analyses confirm efficacy: Separate meta-analyses for myofascial neck pain and upper-trapezius trigger points both found significant improvements in pain, disability, and function.
- Outperformed physiotherapy in direct comparison: An RCT comparing high-intensity laser therapy with standard ultrasound-based physiotherapy found laser significantly more effective across all measured outcomes for chronic nonspecific neck pain.
- Benefits sustained at 12 to 22 weeks: Multiple trials with follow-up of 12 to 22 weeks show effects persisting beyond the treatment course.
What convinced me was the network meta-analysis. Laser therapy didn't just outperform placebo; it outperformed every other physical modality they tested it against. That combined with the Lancet data on chronic pain lasting 22 weeks, and you have an evidence base I can actually defend to a skeptical colleague. The negative trials in the literature almost all come down to dose. Give a subtherapeutic dose, get a null result. That's not the therapy failing. That's the protocol failing.— Dr. William Carter, MD
The Lancet Meta-Analysis: Foundation of the Evidence
Chow et al. (2009) published the seminal systematic review and meta-analysis in The Lancet, analyzing 16 RCTs with 820 participants.
For acute neck pain, patients were about 1.7 times more likely to improve than with placebo (relative risk 1.69, 95% CI 1.22–2.33). For chronic neck pain, the benefit was larger: patients were about four times more likely to get relief (relative risk 4.05, 95% CI 2.74–5.98). Across 11 chronic-pain trials, pain intensity fell by an average of 19.9 mm on the 100 mm scale (95% CI 10.0–29.7), a clinically meaningful drop, and disability improved significantly too.
The review found that dose mattered: trials using adequate doses tended to show benefit, while underpowered protocols did not, which helps explain why some individual trials found no effect. The specific per-point energy values sometimes quoted from this paper could not be confirmed against the primary source, so they are not reproduced here; the reliable takeaway is the adequate-versus-subtherapeutic pattern, not a precise number. The practical wavelength-and-dose discussion lives in the LED vs. Laser for Neck Pain review.
The result has a known statistical caveat. A 2010 Lancet correspondence by Shiri and Viikari-Juntura noted that heterogeneity across the pooled trials was high (I²=89% for acute pain, I²=91% for chronic pain intensity) and that the original analysis used a fixed-effects model. Re-running the analysis under a random-effects model (generally preferred when heterogeneity is high) the acute neck pain result no longer reached significance, and the chronic-pain confidence intervals widened. The chronic-pain finding remained significant under both models, which is why the chronic-pain evidence is treated here as the firmer half of the Lancet result.
Network Meta-Analysis and Systematic Reviews
Hao et al. (2025) compared six biophysical agents head-to-head in a network meta-analysis: TENS, interferential current, extracorporeal shockwave therapy, therapeutic ultrasound, low-level laser therapy, and high-intensity laser therapy. High-intensity laser therapy ranked first for neck pain reduction, followed by shockwave therapy, interferential current, TENS, low-level laser therapy, and ultrasound. Both laser types outperformed placebo, with low-level laser fifth of six.
Tehrani et al. (2022) pooled 13 RCTs for myofascial neck pain syndrome and found low-level laser therapy produced significant improvements in pain, disability, pressure tenderness, and range of motion. Alayat et al. (2022) pooled 17 studies covering 944 patients with upper-trapezius pain and confirmed photobiomodulation reduced trigger-point pain. Cidral-Filho et al. (2024) reviewed 36 clinical studies of photobiomodulation for neck and shoulder pain and reported promising results for pain relief and function. de la Barra Ortiz et al. (2024) focused specifically on high-intensity laser therapy for neck pain and found significant pain reductions.
Landmark Individual RCTs
Kenareh et al. (2021), laser versus ultrasound-based physiotherapy. A single-blind RCT in office workers with chronic nonspecific neck pain compared high-intensity laser therapy with standard ultrasound-based physiotherapy. Kenareh et al. found laser reduced pain and neck disability significantly more than physiotherapy, with the difference holding at the two-week follow-up.
Rampazo et al. (2024), PBM versus TENS versus sham. A double-blind, sham-controlled trial compared photobiomodulation, TENS, the two combined, and sham. Rampazo et al. found both photobiomodulation and TENS reduced pain during movement more than sham; the combination did not beat either alone, suggesting photobiomodulation provides meaningful benefit on its own.
Konstantinović et al. (2010), acute radiculopathy. A double-blind, placebo-controlled RCT in patients with acute neck pain and radiculopathy found low-level laser therapy significantly reduced arm pain versus placebo, notable for targeting radicular pain specifically.
Ince et al. (2023), cervical radiculopathy. A 90-patient RCT randomized patients to high-intensity laser plus exercise, placebo plus exercise, or exercise alone. Ince et al. found the laser group improved significantly more in arm pain, neuropathic pain, neck disability, and quality of life at both 4 and 12 weeks.
Momenzadeh et al. (2022), chronic nonspecific neck pain. A sham-controlled trial found low-level laser therapy significantly reduced pain versus sham, reinforcing the Lancet findings with a more recent trial.
Jiang et al. (2025), wearable LED device. A small self-controlled pilot study with no placebo group tested a wearable 660 nm red-light LED device: pain and neck-function scores held flat during a four-week no-treatment wait, then improved after four weeks of use, and a pain-signaling chemical (substance P) decreased. It is a promising first human signal that home LED devices may help, not proof, and it sits alongside the laser evidence rather than replacing it. The device questions are covered in LED vs. Laser for Neck Pain.
Labanca et al. (2025), multi-wave locked system laser. A double-blind, placebo-controlled pilot RCT of a multi-wave locked system laser for chronic nonspecific neck pain reported significant outcomes, adding to the evidence for this condition. As a pilot, it is small, and a larger confirmatory trial would strengthen it.
Head-to-Head Comparisons with Other Modalities
The trial record includes several direct comparisons against standard physical-therapy modalities. Against ultrasound-based physiotherapy, Kenareh et al. (2021) found laser superior for chronic nonspecific neck pain. Against combined ultrasound and TENS, Venosa et al. (2019) found 1064 nm high-intensity laser superior for cervical spondylosis, and Yilmaz et al. (2020) found it superior for cervical disc-related pain. Against TENS directly, Rampazo et al. (2024) found photobiomodulation and TENS comparable, both beating sham.
Taken together with the network meta-analysis ranking, these direct comparisons show photobiomodulation performing as well as or better than every standard physical-therapy alternative it has been tested against. None of the comparison trials found laser inferior.
Why Treatment Parameters Matter
The recurring lesson across this literature is that dose and coverage determine outcomes. Trials delivering an adequate dose tended to succeed; trials using underpowered protocols, often older studies with weaker devices, tended to produce weak or null results. This adequate-versus-subtherapeutic pattern is the most common explanation for conflicting findings in the field. It is also the kind of explanation that, if overused, makes a therapy unfalsifiable, which is worth noting even though the dose-response pattern in the Lancet data is genuine.
In the Lancet trials, treatment was applied across the cervical region rather than at a single spot; laser was applied to an average of about 11 points, over a course of roughly 10 sessions. Positive trials generally used several sessions per week over a few weeks. The specific energy-per-point figures often attached to these recommendations could not be verified against the primary source and are therefore not stated here; the dependable principle is adequate dose spread across the neck, not a single precise number. The applied wavelength-and-dose detail belongs in the LED vs. Laser for Neck Pain and how red light therapy works guides.
Conclusion
The evidence for photobiomodulation in neck pain forms a coherent picture across more than two decades of research. A Lancet meta-analysis established efficacy for chronic neck pain. A 2025 network meta-analysis ranked high-intensity laser therapy first among six physical-therapy modalities. Condition-specific meta-analyses confirmed benefits for myofascial pain, and individual RCTs show consistent superiority or equivalence to standard alternatives. The therapy works across multiple neck pain conditions (chronic nonspecific pain, myofascial pain, cervical spondylosis, radiculopathy), with the strongest base in myofascial and chronic nonspecific neck pain.
The open question is how to deliver it well: an adequate dose spread across the cervical region, not a single point, and enough sessions to matter. For how that translates into a device worn on the neck, see how CuraYou's ProWave Deep Healing Pad applies red and infrared light to the cervical area.
