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5 Clinical Studies that Demonstrate the Pain-Relieving Benefits of Red Light Therapy

In a recent post on the Joovv blog, we listed 6 different clinical studies that support the anti-aging benefits of red light therapy.  

Red light therapy really does work. Not only can it help to rejuvenate your skin, but it can also help to reduce joint pain and inflammation.

In this article, we'd like to point you to 5 different clinical studies that demonstrate the pain-relieving benefits of red light therapy.  So if you're feeling studious, let's dive in...

The efficacy of low-power lasers in tissue repair and pain control: a meta-analysis study

SOURCE: Photomed Laser Surg. 2004 Aug;22(4):323-9

BACKGROUND: Low-power laser devices were first used as a form of therapy more than 30 years ago. However, their efficacy in reducing pain or promoting tissue repair remains questionable.

METHODS: Following a literature search, studies meeting our inclusion criteria were identified and coded. Then, the effect size of laser treatment, that is, Cohen's d, was calculated from each study using standard meta-analysis procedures.

RESULTS: 34 peer-reviewed papers on tissue repair met our inclusion criteria and were used to calculate 46 treatment effect sizes. 9 peer-reviewed papers on pain control met the inclusion criteria and were used to calculate 9 effect sizes. Meta-analysis revealed a positive effect of laser phototherapy on tissue repair (d = +1.81; n = 46) and pain control (d = +1.11; n = 9). The positive effect of treatment on specific indices of tissue repair was evident in the treatment effect sizes determined as follows: collagen formation (d = +2.78), rate of healing (d = +1.57), tensile strength (d = +2.13), time needed for wound closure (d = +0.76), tensile stress (d = +2.65), number and rate of degranulation of mast cells (d = +1.87), and flap survival (d = +1.95). Further, analysis revealed the positive effects of various wavelengths of laser light on tissue repair, with 632.8 nm having the highest treatment effect (d = +2.44) and 780 nm the least (d = 0.60). The overall treatment effect for pain control was positive as well (d = +1.11). The fail-safe number-that is, the number of studies in which laser phototherapy has negative or no effect-needed to nullify the overall outcome of this analysis was 370 for tissue repair and 41 for pain control.

CONCLUSION: These findings mandate the conclusion that laser phototherapy is a highly effective therapeutic armamentarium for tissue repair and pain relief.

Healthy Pain-Free Woman

Efficacy of low-level laser therapy in the management of neck pain: a systematic review and meta-analysis of randomized placebo or active-treatment controlled trials

SOURCE: The Lancet. 2009 Dec 5;374(9705):1897-1908. Epub 2009 Nov 13

BACKGROUND: Neck pain is a common and costly condition for which pharmacological management has limited evidence of efficacy and side-effects. Low-level laser therapy (LLLT) is a relatively uncommon, non-invasive treatment for neck pain, in which non-thermal laser irradiation is applied to sites of pain. We did a systematic review and meta-analysis of randomized controlled trials to assess the efficacy of LLLT in neck pain.

METHODS: We searched computerized databases comparing efficacy of LLLT using any wavelength with placebo or with active control in acute or chronic neck pain. Effect size for the primary outcome, pain intensity, was defined as a pooled estimate of mean difference in change in mm on 100 mm visual analogue scale.

RESULTS: We identified 16 randomized controlled trials including a total of 820 patients. In acute neck pain, results of two trials showed a relative risk (RR) of 1·69 (95% CI 1·22–2·33) for pain improvement of LLLT versus placebo. Five trials of chronic neck pain reporting categorical data showed an RR for pain improvement of 4·05 (2·74–5·98) of LLLT. Patients in 11 trials reporting changes in visual analogue scale had pain intensity reduced by 19·86 mm (10·04–29·68). Seven trials provided follow-up data for 1–22 weeks after completion of treatment, with short-term pain relief persisting in the medium term with a reduction of 22·07 mm (17·42–26·72). Side-effects from LLLT were mild and not different from those of placebo.

CONCLUSION: We show that LLLT reduces pain immediately after treatment in acute neck pain and up to 22 weeks after completion of treatment in patients with chronic neck pain.

In chronic low back pain, low level laser therapy combined with exercise is more beneficial than exercise alone in the long term: a randomized trial

SOURCE: Aust J Physiother. 2007;53(3):155-60

BACKGROUND: Is low level laser therapy an effective adjuvant intervention for chronic low back pain?  

OBJECTIVE: Randomized trial with concealed allocation, blinded assessors and intention-to-treat analysis.

METHODS: Sixty-one patients who had low back pain for at least 12 weeks.  One group received laser therapy alone, one received laser therapy and exercise, and the third group received placebo laser therapy and exercise. Laser therapy was performed twice a week for 6 weeks.  Outcomes were pain severity measured using a 10-cm visual analogue scale, lumbar range of motion measured by the Schober Test and maximum active flexion, extension and lateral flexion, and disability measured with the Oswestry Disability Index on admission to the study, after 6 weeks of intervention, and after another 6 weeks of no intervention.

RESULTS: There was no greater effect of laser therapy compared with exercise for any outcome, at either 6 or 12 weeks. There was also no greater effect of laser therapy plus exercise compared with exercise for any outcome at 6 weeks. However, in the laser therapy plus exercise group pain had reduced by 1.8 cm (95% CI 0.1 to 3.3, p = 0.03), lumbar range of movement increased by 0.9 cm (95% CI 0.2 to 1.8, p < 0.01) on the Schober Test and by 15 deg (95% CI 5 to 25, p < 0.01) of active flexion, and disability reduced by 9.4 points (95% CI 2.7 to 16.0, p = 0.03) more than in the exercise group at 12 weeks.

CONCLUSION: In chronic low back pain, low level laser therapy combined with exercise is more beneficial than exercise alone in the long term.

The effect of two phototherapy protocols on pain control in orthodontic procedure: a preliminary clinical study

SOURCE: Lasers Med Sci. 2011 Sep;26(5):657-63. Epub 2011 May 31

BACKGROUND: Phototherapy with low-level coherent light (laser) has been reported as an analgesic and anti-inflammatory as well as having a positive effect in tissue repair in orthodontics. However, there are few clinical studies using low-level LED therapy (non-coherent light). 

OBJECTIVE: The aim of the present study was to analyze the pain symptoms after orthodontic tooth movement associated with and not associated with coherent and non-coherent phototherapy.

METHODS: Fifty-five volunteers (mean age = 24.1 ± 8.1 years) were randomly divided into four groups: G1 (control), G2 (placebo), G3 (protocol 1: laser, InGaAlP, 660 nm, 4 J/cm(2), 0.03 W, 25 s), G4 (protocol 2: LED, GaAlAs, 640 nm with 40 nm full-bandwidth at half-maximum, 4 J/cm(2), 0.10 W, 70 s). Separators were used to induce orthodontic pain and the volunteers pain levels were scored with the visual analog scale (VAS) after the separator placement, after the therapy (placebo, laser, or LED), and after 2, 24, 48, 72, 96, and 120 h.

RESULTS: The laser group did not have statistically significant results in the reduction of pain level compared to the LED group. The LED group had a significant reduction in pain levels between 2 and 120 h compared to the control and the laser groups. 

CONCLUSION: The LED therapy showed a significant reduction in pain sensitivity (an average of 56%), after the orthodontic tooth movement when compared to the control group.

Healthy Pain-Free Runner

Efficacy of low level laser therapy associated with exercises in knee osteoarthritis: a randomized double-blind study

SOURCE: Clin Rehabil. 2012 Jun;26(6):523-33. Epub 2011 Dec 14

OBJECTIVE: To estimate the effects of low level laser therapy in combination with a program of exercises on pain, functionality, range of motion, muscular strength and quality of life in patients with osteoarthritis of the knee.

BACKGROUND: A randomized double-blind placebo-controlled trial with sequential allocation of patients to different treatment groups.

METHODS: 40 participants with knee osteoarthritis, 2-4 osteoarthritis degree, aged between 50 and 75 years and both genders.  Participants were randomized into one of two groups: the laser group (low level laser therapy dose of 3 J and exercises) or placebo group (placebo laser and exercises).  Pain was assessed using a visual analogue scale (VAS), functionality using the Lequesne questionnaire, range of motion with a universal goniometer, muscular strength using a dynamometer, and activity using the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) questionnaire at three time points: (T1) baseline, (T2) after the end of laser therapy (three weeks) and (T3) the end of the exercises (11 weeks).

RESULTS: When comparing groups, significant differences in the activity were also found (P = 0.03). No other significant differences (P > 0.05) were observed in other variables. In the intragroup analysis, participants in the laser group had significant improvement, relative to baseline, on pain (P = 0.001), range of motion (P = 0.01), functionality (P = 0.001) and activity (P < 0.001). No significant improvement was seen in the placebo group.

CONCLUSION: Our findings suggest that low level laser therapy, when associated with exercises, is effective in yielding pain relief, function and activity on patients with osteoarthritis of the knees.

Summary: There is strong clinical evidence that shows red light therapy can reduce pain and enhance recovery.

We've pointed out 5 different clinical studies that demonstrate the pain-relieving benefits of red light therapy.  This is certainly not an exhaustive list.  If you're anxious to learn more, feel free to search PubMed.   

But remember, when it comes to red light therapy, wavelength and intensity are incredibly important.  Make sure you choose a device that delivers red light with the correct wavelength and an optimal amount of power .