Taddeucci P.D.C. et al. - Photobiomodulation in Trigeminal Neuralgia: A Systematic Review and Meta-Analysis

A systematic review with a meta-analysis published in 2026 included nine randomized controlled trials involving 387 patients with trigeminal neuralgia. Laser photobiomodulation was associated with an average reduction in pain scores of 2.17 points, but there was a very high degree of heterogeneity among the studies.

What this study measured

Trigeminal neuralgia is a severe facial pain that is often difficult to relieve long-term with medication alone. The authors, affiliated with the Division of Oral Medicine at the Pontifical Catholic University of Rio Grande do Sul, sought to determine whether laser photobiomodulation reduces pain in this condition and in postherpetic neuralgia.

The search covered PubMed, Web of Science, LILACS, EMBASE, Scopus, and the Cochrane Library, and included only randomized controlled trials. No studies on postherpetic neuralgia met the inclusion criteria; this subgroup was therefore excluded. Nine trials were included, involving a total of 387 patients. In seven of these trials, patients also received drug therapy, which was initiated before or during photobiomodulation. Six trials used a sham laser as the comparator. The abstract does not mention a PROSPERO registration.

Key Findings

Qualitative analysis and quantitative analysis point in the same direction, but with different levels of confidence.

• Eight out of nine trials reported a significantly greater reduction in pain scores in the photobiomodulation groups than in the control groups.
• Meta-analysis of five trials: mean difference of -2.17 points (95% CI: -3.30 to -1.04; p = 0.0002).
• Statistical heterogeneity: I² = 92%, a value considered very high.
• Low to moderate risk of bias in two-thirds of the included studies.

The authors conclude that photobiomodulation appears to be an effective adjunctive therapy, with a favorable safety profile and the potential to reduce dependence on medication. The term “adjunctive” is important: in most trials, it was added to the treatment without replacing it.

How photobiomodulation works for this indication

The mechanism remains hypothetical and has not been explored in this review. Red and near-infrared light is thought to be absorbed by mitochondrial cytochrome c oxidase, which would increase ATP production in the irradiated nervous tissue. With regard to neuropathic pain, effects such as modulation of local inflammation, a reduction in oxidative stress, and an effect on nerve conduction are also suggested. These hypotheses have yet to be confirmed for this indication.

Limits You Should Know

These issues are significant, and the authors do not downplay them. A 92% heterogeneity indicates that results vary considerably from one trial to another, which weakens the average estimate of 2.17 points. Photobiomodulation parameters varied widely and were often incompletely reported, preventing any rigorous comparison between protocols. The meta-analysis is based on only five of the nine trials, and one-third of the studies had a risk of bias rated as moderate or higher. Long-term follow-up data are limited. Finally, the specific effect of photobiomodulation is difficult to isolate, as most patients were receiving concurrent treatment. No GRADE assessment is reported.

What This Means in Practice

The evidence is consistent, with eight out of nine studies pointing in the same direction, but the quality of the evidence does not support a firm recommendation. Photobiomodulation is presented here as a possible adjunct to drug therapy, not as an alternative. This summary does not specify a reference wavelength, power level, or number of sessions, precisely because these parameters were too variable and poorly documented.

Frequently Asked Questions

Is photobiomodulation effective against trigeminal neuralgia?

In this meta-analysis, it was associated with an average reduction in pain scores of 2.17 points compared with the control group—a statistically significant result—and eight out of nine trials showed similar findings. However, the very high heterogeneity means this figure should be interpreted with caution.

How many sessions are needed?

This review does not provide an answer. The authors note that the parameters—including the number and frequency of sessions—varied widely from one trial to another and were often incompletely reported. To date, no standardized protocol has emerged.

Can it replace medication?

No, and the study does not suggest that. In seven of the nine included trials, patients received medication in addition to photobiomodulation. The authors describe it as an adjunctive therapy. Any changes to your treatment should be discussed with your doctor.

Reference

Taddeucci PDC, Louzeiro GC, Cherubini K, Spanemberg JC, Salum FG. Effectiveness of laser photobiomodulation in the management of trigeminal neuralgia: a systematic review and meta-analysis. Lasers in Medical Science, 2026. PMID 41629512. View the study on PubMed

This summary is provided for informational purposes only and does not constitute medical advice. Photobiomodulation is not a substitute for prescribed treatment. Consult a healthcare professional.