Red Light Therapy for Myofascial Pain: Scientific Evidence

43 women took part in a 2021 randomized clinical trial testing whether photobiomodulation (PBM) added meaningful benefit to dry needling for myofascial pain in the upper trapezius, across 3 groups: dry needling plus PBM, dry needling only, and dry needling outside the trigger point. Each group received 1 dry needling session followed by PBM at 640, 875, and 905 nm with the machine on or off, with pain, disability, pain pressure threshold, and muscle activity tracked before, at 10 and 30 minutes, at 1 week, and at 1 month. The study concluded that adding PBM to dry needling produced similar results to dry needling alone, while dry needling outside the trigger point showed better pain and disability outcomes than direct trigger point needling.

Polarized low-level laser therapy and standard low-level laser therapy (LLLT) were compared for myofascial pain in the trapezius muscles in a 2020 observational study of 64 patients randomly divided into 2 equal groups. Both groups received polarized low-level laser therapy (PLLLT) or LLLT at 755 nm, 160 mW, and 6 J/cm² for 5 sessions per week over 14 days, applied to trigger points in the trapezius, with pain, referred pain, neck movement, and muscular taut band measures assessed at sessions 1, 5, and 10. Both treatments significantly reduced all measures by the 10th session, but LLLT showed significantly greater pain reduction than PLLLT, leading researchers to recommend LLLT as the more effective option for trapezius myofascial pain.

In 2018, a randomized controlled trial of 61 adults compared soft laser therapy against shockwave therapy for trapezius myofascial pain and found shockwave may have come out ahead on most measures. 31 patients received soft laser at 780 to 830 nm, 100 mW to 4 W, and 3 to 9 J/cm² for 2 minutes per session once daily over 3 weeks, while 30 received shockwave therapy once weekly for 3 weeks, with resting pain, pain tolerance, neck disability, and quality of life assessed at baseline, week 3, and week 15. While both groups improved significantly, shockwave showed greater gains in pain tolerance, neck function, and all SF-36 domains, while laser showed a larger resting pain reduction at week 15 only, and no side effects were observed in either group.

When laser therapy and shock wave therapy were put side by side for upper trapezius myofascial pain in a 2016 observational study of 46 patients, laser appeared to deliver quicker results, but both treatments ended up equally effective at 1 month. 20 patients (1 man and 19 women, mean age 45.3) received laser at 780 to 830 nm, 100 mW, 6 J/cm², and 10 Hz for 3 minutes per session, 3 to 10 times weekly over 14 days alongside exercise and medication, while 26 (2 men and 24 women, mean age 42.3) received shock wave therapy with the same additions, with pain, neck disability, and shoulder disability assessed before, after, and at 1 month. The study found the advantage for laser on pain and neck disability scores at 2 weeks did not carry through to the 1-month follow-up.

2 different laser approaches were tested against placebo for shoulder myofascial pain in a 2016 observational study of 30 patients: intravenous laser therapy (IVL) at 810 nm and 60 mW, and percutaneous low-level laser (PLLL) at 632.8 nm and 2 mW, both delivered at 20.35 J/cm² for 5 to 20 minutes per session, 12 times weekly over 28 days. All patients also received posture training, trigger point massage, stretching, and 10 mg nightly nortriptyline for 3 months. Both IVL and PLLL significantly reduced pain intensity and disability and improved quality of life compared with placebo, with no side effects recorded and no significant difference found between the 2 active treatments.

A 2015 double-blind randomized controlled trial evaluated the effect of high-intensity laser therapy (HILT) on chronic myofascial pain in the trapezius muscle in female patients, with one group assigned to HILT plus exercise and another to sham therapy plus exercise. HILT was delivered at 1064 nm with a total energy of 1060 J over 21 days, applied to the trapezius muscle, with pain, cervical range of motion, neck disability, and quality of life assessed at baseline, week 4, and week 12. Both groups improved significantly on all measures, but researchers found the HILT group showed significantly greater improvements in pain scores, the Neck Disability Index, and multiple quality of life domains at both week 4 and week 12.

Both LLLT and electrical stimulation added to stretching were associated with significantly lower pain scores than stretching alone at 1 month in a 2015 observational study of 47 patients with myofascial pain in the upper trapezius. The LLLT group received 670 nm light at 5 mW, 4 J/cm², and 10 Hz for 10 minutes per session, 10 times weekly over 10 to 14 days combined with stretching, while the IMS group received electrical stimulation plus stretching and the control group stretched only. Researchers also found that pain threshold was significantly higher in the IMS group than in the stretching-only group at 1 month.

5 groups were compared in a 2014 double-blind randomized placebo-controlled trial testing low-level laser therapy (LLLT) and ultrasound as stand-alone treatments for myofascial pain in the upper trapezius in 60 participants (28 women and 32 men, mean age 24.5 years). The active LLLT group of 11 received 904 nm light at 30 mW, 22.5 mW/cm², and 18 J for 10 minutes per session, 5 times weekly over 10 treatments, applied to trigger points in the upper trapezius, alongside 11 placebo LLLT, 12 active ultrasound, 12 placebo ultrasound, and 14 no-therapy control participants. All groups improved significantly in pressure pain threshold, pain scores, and cervical lateral flexion at 2 weeks and at 12-week follow-up, but no significant difference was found between active therapies and their respective placebos, while both outperformed the no-therapy control.

A 2004 randomized controlled trial evaluated the effect of gallium arsenide (GaAs) low-level laser therapy (LLLT) on pain, functional ability, and quality of life in 60 patients with chronic myofascial pain in the neck, randomly assigned to 30 active laser and 30 placebo laser. The active group received GaAs LLLT at 904 nm, 2 J/cm², 11.2 mW, and 2800 Hz for 3 minutes per session, 10 times weekly over 14 days to trapezius trigger points in the neck, with follow-up assessed at baseline, 2, 3, and 12 weeks. All outcome measures improved significantly in the active laser group (p < .01), and 63% of laser patients rated themselves improved versus only 19% in the placebo group.

Placebo laser, dry needling, and helium-neon (He-Ne) laser were compared head-to-head for myofascial pain in the upper trapezius in a 2004 placebo-controlled randomized controlled trial of 60 patients, all of whom were also taught stretching exercises. The He-Ne laser group received 632.8 nm light at 2 J applied to 3 trigger points on both sides of the upper trapezius, 12 times weekly over 28 days, while the dry needling and placebo laser groups followed the same stretching program with their respective treatments. The study reported significant short-term reductions in pain at rest and on activity, and better functional scores in the laser group compared with both other groups, but those differences were not observed at 6-month follow-up.

Individuals receiving infrared laser showed greater pain relief and higher serotonin levels than the sham group in a 2004 double-blind randomized controlled trial testing infrared (IR) laser on myofascial pain in 46 patients, all of whom also received medical treatment. The IR laser group received 904 nm light at 1.44 J/cm² applied to trigger points for 3 minutes once daily over 10 days, while the control group received sham laser with the same medical treatment. The study reported a statistically significant difference in pain scores between groups and concluded that IR laser may be an effective treatment for myofascial pain that also raises serotonin, an important mediator of pain inhibition.

Pain scores dropped more than twice as much in the laser group as in the stretching-only group in a 2003 randomized controlled trial testing low-level laser therapy (LLLT) plus stretching against stretching alone in 62 patients with myofascial pain involving active trigger points in the neck and upper back. The LLLT group received 780 nm light at 5 J/cm² and 5 to 10 mW for 3.27 minutes per session, 10 times weekly over 10 days, applied to the trapezius and levator scapulae. Mean pain fell from 7.54 to 3.06 in the LLLT group versus 7.03 to 5.19 in the stretching-only group, and significant favorable differences were found for the LLLT group across all other measures at both follow-up points.

A clinical trial in 1996 assessed the effect of low-level laser therapy (LLLT) on myofascial pain in 243 patients aged 16 to 80, covering conditions ranging from neck and shoulder pain to epicondylitis, low back pain, and Achilles tendinitis. Patients received active LLLT at 632.8, 820 to 830, or 904 nm at 120 mW with energy doses of 2.5 to 60 J per point in 30-second contact sessions, while the opposite side of each patient received sham irradiation as a control. Researchers reported that acute pain reduced by more than 70% and chronic pain by more than 60% at 3 months, with stiffness decreasing and mobility improving, and no negative effects were observed.

Treatment and placebo groups were compared in a 1989 double-blind randomized controlled trial testing helium-neon (He-Ne) laser irradiation on skin resistance and pain at trigger points in the neck and low back in 24 patients with myofascial pain. Each participant received 3 twenty-second applications of the He-Ne laser at 632.8 nm and 0.95 mW, delivering 0.014 to 0.029 J per session at a near-contact distance, 3 times weekly, while the control group received sham stimulation using the same procedure. Results reported a statistically significant increase in skin resistance (p < .001) and a decrease in pain scores (p < .005) in the laser group, and researchers suggested the He-Ne laser as an effective adjunct to conventional physical therapy for myofascial pain.

18 patients (11 men and 7 women) with myofascial pain involving 31 active trigger points in the neck, shoulder, arm, and leg muscles took part in a 1989 observational study comparing infrared laser therapy (ILT) against placebo at trigger points. Trigger points were randomized to receive either ILT at 904 nm, 1.5 J per point, and 1400 Hz for 3 minutes twice weekly, or placebo laser, with pain threshold measured before, immediately after, and 15 minutes after treatment. In the end, the study reported a significant increase in pain threshold in the ILT group immediately after treatment and a greater increase at 15 minutes, with non-treated points on the opposite side also showing a significant rise at 15 minutes.

A 1989 double-blind randomized controlled trial tested pulsed infrared laser (PIL) against placebo for myofascial pain in the cervical region and found significantly greater pain reduction in the PIL group at both the end of therapy and at 3-month follow-up. Patients received 12 sessions on alternate days, with 5 J applied per session at 780 to 1400 nm to the 4 most painful trigger points and 5 bilateral acupuncture points, while the placebo group underwent the same procedure with a nonoperational device. Pain was monitored using the McGill pain questionnaire and the visual analog scale, and the study reported the PIL group showed significantly greater pain reduction than the placebo group at both time points.

No statistical difference between laser and placebo was found in a 1988 crossover, double-blind, clinical trial. It tested low-output helium-neon laser therapy (He-Ne laser) at 633 nm for chronic myofascial pain in 62 patients. Patients received 2 sessions of 5 treatments each, given 6 weeks apart, applied to acupuncture points and trigger points, with clinical responses assessed using the McGill Pain Questionnaire. The study concluded that the He-Ne laser showed no advantage over placebo under this treatment regimen.

Laser and placebo groups were compared in a 1986 randomized controlled trial examining the effect of helium-neon (He-Ne) laser on skin resistance at musculoskeletal trigger points associated with myofascial pain in the upper back, lower back, and neck in 30 patients. Both groups received standard physical therapy, with the laser group additionally receiving 3 fifteen-second applications at 632.8 nm, 0.95 mW, and 0.0143 to 0.029 J/cm² per session, 3 times weekly. Researchers noted a statistically significant increase in skin resistance in the laser group (p < .007), and suggested this change can accompany resolution of the underlying condition.

64 patients with chronic myofascial pain in the neck, aged 20 to 60 (55 females and 9 males across both groups), were randomly assigned to active or placebo gallium arsenide aluminum (Ga-As-Al) laser in a 2007 prospective double-blind randomized controlled trial. The active group received 830 nm laser at 450 mW, 58 mW/cm², and 1000 Hz for 2 minutes per point applied to 3 trigger points bilaterally in the neck, once daily over 15 sessions, while both groups also performed daily isometric and stretching exercises. Both groups improved from baseline on pain, cervical range of motion, and neck disability, but no significant difference between the laser and placebo groups was found on any measure.

When a gallium arsenide (GaAs) laser and placebo were tested head-to-head for myofascial pain in the neck in a 2005 double-blind randomized controlled trial of 53 patients (35 females and 18 males), neither treatment came out ahead. Of the 48 analyzed (32 females and 16 males), 23 received GaAs laser at 904 nm and 1000 Hz for 2 minutes per point once daily over 14 days to 3 trigger points and 1 taut band point in the trapezius on each side, while 25 received the device switched off, with all patients also performing daily isometric exercises and stretching. Pain, pressure pain threshold, and neck range of motion improved in both groups by weeks 2 and 14, but no significant between-group difference was found.

47 female laboratory technicians (out of 52 volunteers enrolled) with myofascial pain in the neck and shoulder girdle took part in a 1992 double-blind, cross-over randomized controlled trial evaluating the effect of low-level laser therapy (LLLT) on tender points. Each participant received 6 active LLLT sessions and 6 placebo sessions applied at 830 nm and 30 mW, delivering 0.9 and 9 J per session in 60 seconds, 6 times weekly over 35 days, with tender points in the neck and shoulder girdle as the treated area. Participants rated the placebo as significantly more beneficial than the active laser (p = .04), and it was reported that there was no reduction in analgesic use and no difference in pain scores between the laser and placebo conditions. The study suggested that the positive placebo response may have been driven by therapist influence rather than any effect of the laser itself.