Does Red Light Therapy Work for Lower Back Pain?

A little, at best, and only for a few weeks. Some reviews found that red and near-infrared light eased chronic back pain slightly more than a fake treatment, but the largest placebo trial found no difference at all. No review found that it helps people move or function better.

In research papers, red light therapy goes by two names: low-level laser therapy (LLLT) and photobiomodulation. Both mean shining low-power red or near-infrared light on the skin. Near-infrared light sits just past visible red, so you cannot see most of it.

Almost all of these trials studied nonspecific low back pain. That means back pain with no single cause found, such as a fracture, infection or pinched nerve. It is the most common kind.

What the Data Show

The best-known summary is the Cochrane review. Cochrane is a group that pools trials using strict methods. Its 2007 review of six randomized trials found some evidence that laser therapy relieved pain more than sham (fake) therapy in subacute and chronic low back pain. The relief showed up only in short-term and intermediate-term follow-up, and no trial reported long-term results. There was no difference in pain-related disability. Two trials found fewer relapses with laser at six months, and no side effects were reported. The authors concluded the data were too thin for firm conclusions.

The 2008 update of that review, covering seven trials, was more blunt. Three small studies with 168 people showed pain relief that was statistically significant but clinically unimportant, meaning too small for most people to notice. Two small trials with 151 people again found a lower relapse rate at six months.

Later reviews split.

A 2015 meta-analysis of seven trials with 394 patients found that laser lowered pain scores by about 13.6 points more than placebo, on a scale usually scored 0 to 100. It found no effect on disability or how far people could bend.
A 2016 meta-analysis of 15 trials with 1,039 people found pain fell up to 1.4 points more on a 10-point scale with laser. People in those trials were about twice as likely to rate themselves improved right after treatment.
A 2020 review of 12 trials with 1,046 people judged the effect on pain and disability clinically unimportant compared with sham. It concluded the evidence does not support using light therapy for nonspecific back pain.

The best single trial points the same way as that last review. In a randomized trial of 148 people with chronic back pain, with patients, therapists and assessors all blinded, 12 sessions over 4 weeks did no better than placebo for pain or disability. The difference in pain between groups was 0.01 points.

Why Do the Studies Disagree?

Dose is the biggest reason. In the 15-trial meta-analysis, the benefit appeared only in trials that delivered at least 3 joules (a unit of light energy) per treatment point. It also appeared only in people whose pain had lasted less than 30 months, and only when the light was not applied to acupuncture points.

Light also has a “sweet spot.” A review of how this therapy works describes a two-sided dose response: low levels of light stimulate cells, while high levels inhibit them. Too little does nothing, and too much may work against you.

The Cochrane authors flagged the same problem back in 2007. They wrote that comparing laser treatments will make more sense once dose calculation methods are harmonized. That still has not happened, so two trials that look alike may deliver very different treatments.

How Is Red Light Supposed to Help Back Pain?

The theory is about cell energy and inflammation. According to that mechanisms review, red and near-infrared light is absorbed by an enzyme called cytochrome c oxidase inside mitochondria, the parts of the cell that make energy. That leads to more ATP, the cell’s fuel, along with a rise in nitric oxide. The review calls lower inflammation one of the most reproducible effects of this therapy.

The same review draws much of that evidence from animal models of disease. Nonspecific back pain often has no single inflamed spot to aim at, which may be one reason the results in people are so mixed.

Does Red Light Therapy Help a Herniated Disc or Degenerative Disc Disease?

The evidence here is thin, and it is not encouraging. In a double-blind trial of 80 people with back pain from a herniated disc, half with recent pain and half with long-term pain, everyone got a hot pack plus either real or placebo laser for 15 sessions over 3 weeks. All four groups improved, and real laser did no better than placebo laser for pain or function.

No trial in people has tested red light therapy for degenerative disc disease, the age-related wear of the discs between the bones of the spine. Lab studies on disc cells exist, but a dish of cells is not a back.

Leg pain that runs below the knee, numbness, or weakness in a foot points to a pinched nerve. That needs an exam, not a light panel.

Do Home Red Light and Infrared Devices Work for Back Pain?

Two small home-use trials disagree.

In a trial of 39 people with chronic back pain lasting over six years, a battery-powered infrared waistband (800 to 1200 nanometers) was compared with an identical unit that was switched off. Over seven weekly sessions, average pain fell from 6.9 to 3 out of 10 with the real device and from 7.4 to 6 with the placebo. That is a big gap, but the trial was small and came from one pain clinic.

A newer double-blind home trial of 30 people used a portable multi-wavelength laser for 20 minutes a day, 5 days a week, for 3 weeks. Pain dropped by the same 1.13 points in both groups. The sham device gave off red light with no laser output, so the comparison was laser against plain red light, and they came out even.

Neither trial is large enough to settle the question.

Does Red Light Therapy Work Better With Exercise?

Light on its own does not beat exercise. The 2020 review found no clinically important difference between light therapy and exercise for pain or disability in chronic back pain.

As an add-on, the short-term results are flat. In the Cochrane update, three studies with 102 people found laser plus exercise was no better than exercise in the short term.

One trial found a later payoff. In a randomized trial of 61 people with chronic back pain, laser twice a week for 6 weeks added nothing at the end of treatment. But 6 weeks after treatment ended, the laser plus exercise group had 1.8 points less pain on a 10-point scale and 9.4 points less disability than exercise alone.

Is Red Light Therapy Safe for Your Back?

In the trials, yes. Both Cochrane reviews reported no side effects, the 148-person trial had no adverse events, and neither home-device trial reported any. The main practical risk is to the eyes, so never look into a laser or bright panel and wear the goggles that come with the device.

What Do Doctors’ Guidelines Say?

The American College of Physicians guideline lists low-level laser therapy as one of many first-choice non-drug options for chronic low back pain, alongside exercise, yoga, tai chi, acupuncture and others. It rates the evidence for laser as low quality. Laser is not on the guideline’s list for back pain of recent onset, where heat, massage, acupuncture or spinal manipulation are the options.

Dr. Kumar’s Take

I spend much of my working life on the spine, and I would be glad to see a painless, side-effect-free treatment for back pain prove itself. Red light therapy has not done that yet. The careful, well-blinded trials found little or no difference from a fake device, and none of the reviews found better function, which is what matters for getting back to work and daily life.

That said, it does not appear to cause harm. If a clinic offers it alongside an exercise program, the downside is mostly cost and time. Exercise is what has the stronger record, and the trials suggest light is, at most, a small extra on top of it.

Practical Takeaways

Expect a small effect, if any. The best trials found little or no difference from placebo.
Do not let light replace exercise. Exercise did as well or better in every head-to-head comparison.
Dose matters. Trials that helped delivered at least 3 joules per point, so check a device’s power output, not just its color.
It may suit newer pain better. The benefit showed up mostly in people whose pain had lasted under 30 months.
A herniated disc is not a good target. Laser did no better than placebo in that trial.
Protect your eyes during every session.
See a doctor for leg weakness, numbness, fever, weight loss or trouble controlling your bladder or bowels.

FAQs

What did the Cochrane review find about laser therapy for low back pain?

It found some short-term pain relief compared with sham treatment, but no difference in disability. The 2008 update called the pain relief clinically unimportant. Two small trials found fewer relapses at six months, and the authors said the data were too limited for firm conclusions.

Can red light therapy help degenerative disc disease?

No trial has tested it for degenerative disc disease in people. In a placebo-controlled trial of people with a herniated disc, real laser did no better than a placebo laser.

Is infrared or red light better for back pain?

The infrared waistband trial used 800 to 1200 nanometer light and found a large benefit. In one home laser trial, a laser device did no better than a sham device that gave off plain red light. No trial has compared the two colors head to head for back pain.

How long does it take red light therapy to work on back pain?

Trials ran from 3 to 7 weeks, often with 12 to 15 sessions. Where relief appeared, it was in the short and intermediate term. No trial tested longer courses.

Is red light therapy safe to use on my back at home?

No side effects were reported in the back pain trials, including two home-device trials. Protect your eyes, follow the device instructions, and keep it moving or timed so you do not overheat the skin.

Bottom Line

Red light therapy for lower back pain has a mixed record. Some reviews found a small, short-term drop in pain compared with fake treatment, but the largest well-blinded trial found none, and no review found better function. It appears safe, and a doctors’ guideline lists it as one low-evidence option for chronic back pain. Exercise has the stronger evidence, and light is at most a small extra on top of it.

Does Red Light Therapy Work for Lower Back Pain?