Red Light Therapy for Plantar Fasciitis: The Evidence

The evidence for red and near-infrared light on plantar fasciitis (heel and arch pain from the band of tissue under the foot) is graded Limited. One 2022 meta-analysis of randomized trials includes 11 plantar fasciitis trials and reported less pain after low-level laser than after control, but every trial used a clinical laser on small spots, the plantar results are not reported separately in the sources reviewed here, and no trial tested a home LED panel (PMID 36171024).

Choosing a panel? Our ranking of the best red light therapy panels is computed from published, method-labeled specs across 188 devices. For heel pain, the spec that matters is method-labeled near-infrared irradiance at the distance you would actually use, because the trials turned on delivered dose.

How the grade was reached

The site's evidence grades run from Strong to Insufficient. Plantar fasciitis lands at Limited for four reasons:

• The clinical signal comes from one pooled source, and that source combines plantar fasciitis with Achilles and patellar tendinopathy.
• The text reviewed here does not give a plantar-only effect size, so the condition is graded on the pooled lower-limb result.
• The trials used lasers delivering joules per point, not panels delivering light over an area.
• Follow-up in the pooled analyses ran 4 to 12 weeks, so durability is unknown.

The wider tendon grade on our tendinopathy evidence page is Moderate, because it rests on two meta-analyses and a mechanism trial. A single condition within that group, with one source behind it, is held lower.

The study behind the grade

The 2022 BMJ Open meta-analysis

Naterstad and colleagues pooled 18 randomized trial reports with 784 participants and a mean age of 43.6 years, covering plantar fasciitis (11 trials), Achilles tendinopathy (5) and patellar tendinopathy (2) (PMID 36171024). Ten trials compared laser with placebo, five with other interventions, and three tested laser as an add-on to another treatment. Searches ran to August 2020 and the review was registered in advance.

The trial devices were lasers. Across the included trials the paper reports wavelengths from 635 to 904 nm, mean output power of 7 to 200 mW, 30 to 600 seconds per spot, 0.21 to 8.4 J per spot where reported, and 6 to 24 sessions. Six trials described their dose inadequately.

The pooled results, on a 100 mm pain scale:

Disability also improved against any control, with a standardized mean difference of 0.39 at the end of therapy (95% CI 0.09 to 0.70), which is a small effect. The one trial with a non-recommended dose reported -3.0 mm, not a significant difference. No adverse events were reported in the review. The full breakdown, including the exercise add-on analysis, is in our study review of the Naterstad meta-analysis.

Supporting sources for the tendon group

Two older sources sit beside it. A 2010 review pooled 25 controlled laser trials and reported that the 12 positive ones used doses close to guideline ranges (PMID 19708800); see the Tumilty review. A small 2006 trial measured an inflammatory mediator in the Achilles after 904 nm laser (PMID 16371497); see the Bjordal review. Neither studied the plantar fascia, so they support the dose logic rather than the heel result.

Reading the size of the effect

A difference of about 13 mm on a 100 mm scale is modest. Around 10 mm is often used as a rough point where a patient might notice a change, but that threshold varies, and the intervals here are wide: the recommended-dose placebo comparison ran from 3.74 to 26.22 mm. The honest reading is that the average effect in these trials was probably real but small to moderate, and individual results will vary. Pain scores are also self-reported, which makes them sensitive to expectation.

What was not studied

• Home LED panels. No trial in the 2022 review used a multi-wavelength LED panel on the sole of the foot.
• Plantar-only effect size. The sources reviewed here pool plantar fasciitis with tendinopathy, so a heel-specific estimate is not stated.
• Long-term outcomes. Follow-up ended at 4 to 12 weeks. Whether pain stays lower, or the fascia recovers faster, is not established.
• Comparison with standard care. Five trials compared laser with other interventions, but this page does not draw a conclusion about laser against stretching, footwear changes, orthotics or injections.
• Panel doses. No source defines a dose for a panel at a distance, which spreads light over a large area at lower irradiance than a laser spot.
• Chronic nerve causes. Foot pain from nerve damage is a different question, covered on the chemotherapy neuropathy page and in the best panels for neuropathy and foot pain.

A practical section for panel owners

The sole of the foot is awkward for a panel. Light has to reach the heel and arch from below or from the side, so positioning matters more than for a back or a shoulder.

1. Work out the dose, not the minutes. Take the method-labeled irradiance at your treatment distance, multiply by time, and check the result with the dose calculator. Trial doses are written per point, and our page on WALT dosing recommendations explains why they do not convert directly into panel minutes.
2. Set a repeatable distance. Irradiance falls quickly as you move away, as the distance guide and the inverse square law explainer show. Resting the foot at the same marked spot each session keeps the dose the same.
3. Check the near-infrared share. The trial wavelengths were mostly 810 to 904 nm. Our 810nm page and the wavelengths overview show which bands panels offer, and the irradiance explainer shows how to read the measurement method on a label.
4. Skip the depth worry. The plantar fascia lies close to the skin, so penetration is a smaller concern than for a hip. Coverage and position are the bigger factors, and the targeted versus full panel guide explains the trade-off.
5. Compare like with like. The best panels for joint pain page ranks models on database fields; see how rankings work for the criteria.

For a related tendon with a similar evidence base, see the tennis elbow evidence page, which is also graded Limited.

Cautions

• Heel pain has several causes. A sudden injury, a swollen, hot or very painful heel, numbness, or pain that is not improving should be assessed by a clinician before light is tried.
• Light was studied alone or as an add-on in controlled trials. It was not shown to replace stretching, loading programs or medical care.
• People who are pregnant, have a history of skin cancer over the site, or take photosensitizing medication should speak with a clinician first; see the list of photosensitizing medications.
• Eye protection matters with bright near-infrared sources, even though the band is invisible; see the eye protection guide.
• A few millimeters of change on a 100 mm pain scale should be read as modest.