Red light therapy for Achilles tendonitis and tears – Benefits and drawbacks
- Maryke Louw
- Sep 8
- 9 min read
Updated: Oct 6
One emerging option for the treatment of Achilles tendon injuries is red light therapy, also known as photobiomodulation. This treatment uses specific wavelengths of red or near-infrared light to stimulate cells and tissues. But does it actually help Achilles tendons?
Remember, if you need help with an Achilles injury, you're welcome to consult one of our team via video call.
The terms tendinitis, tendonitis, tendinosis, and tendinopathy mean the same thing for all practical purposes, and we use these interchangeably in most of our articles.
In this article:
This article contains affiliate links. We might earn a small commission on sales at no extra cost to you.
How does red light therapy work?
Red light therapy works by delivering red or near-infrared light into injured tissues. Researchers have found that the most effective ways for delivering red light therapy are by using low level laser and LED devices. Infrared lamps, despite being advertised as red light therapy, don't actually deliver the correct type of light.
This type of light stimulates the mitochondria, which energizes cells and can trigger a healing response. It also reduces excessive inflammation, improves blood flow, and is thought to reduce pain through changes in nerve activity and releasing endorphins.
🤷♀️ But do these effects benefit Achilles injuries? I mean, we know for instance that inflammation is not part of the injury process in chronic Achilles tendonitis or tendinopathy.
Can red light therapy help for Achilles tendonitis/tendinopathy?
Achilles tendinopathy (also called Achilles tendonitis or tendinosis) is an overuse injury which causes pain, stiffness, and reduced strength in the Achilles. Because tendinopathies are notoriously slow to recover, researchers have tested red or infrared light therapies to see if they can improve outcomes.
The scientific evidence so far is mixed but promising in parts. On the positive side, several studies have shown that adding photobiomodulation can lead to faster pain relief and better early-stage healing for Achilles tendinopathy when compared to rehab alone.
For example, one clinical trial combined red light treatments with an eccentric exercise program (a well-known Achilles strengthening routine) and found that the group receiving actual red light therapy had less pain and better function after 12 weeks than the group doing these exercises and receiving a placebo of “fake” red light therapy.
That sounds great – so why do we say the evidence is mixed? Because other research has been less enthusiastic. A 2020 systematic review looked specifically at Achilles tendinopathy patients across multiple trials, and concluded that the results were inconsistent, and the overall evidence quality was low. In that review, some trials showed a short-term pain decrease with red light therapy, but by 3 or 12 months the differences largely evened out.
💡 The bottom line from that review was that there isn’t enough solid evidence to recommend red light or laser therapy as a routine treatment for Achilles tendinopathy. In plain English, it might help, but it’s not a sure thing.
Overall, if you have Achilles tendinopathy, red light therapy is a reasonable adjunct to try if you have the resources – just keep your expectations realistic. You might experience reduced pain and possibly faster progress in the first few weeks of rehab with red light sessions, especially if you follow the guidelines for proper use. But don’t be discouraged if it’s not a miracle cure (see further down).
What about red light therapy for a totally or partially torn Achilles?
Achilles tendon ruptures (full or partial tears) are injuries that typically require either surgical repair or a lengthy period of immobilization and rehab if treated non-surgically.
The healing process for tears is very different from that of tendonitis. Achilles tears go through phases of bleeding, inflammation, collagen repair, and remodelling. The idea of using red light therapy in the early healing phase of an Achilles tear is appealing – in theory, it could reduce excessive inflammation and promote collagen synthesis, potentially helping the tendon heal stronger or faster.
However, clinical evidence in humans with Achilles tears is very limited so far.
A 2022 randomized controlled trial investigated adding photobiomodulation to the standard conservative (non-surgical) treatment for acute Achilles tendon ruptures. Patients in the laser group received red/infrared light treatments on their injured Achilles during the immobilization period (while they were in a boot), and then everyone did the same rehab exercises afterward.
The results? After rehab, both the red-light group and the placebo group improved a lot, but there was no significant difference between them in terms of Achilles functional scores, strength, range of motion, or overall recovery.
The only small advantage noted was that the red light group reported slightly less pain during walking at 12 and 16 weeks post-injury – but this did not translate into measurable functional superiority. The authors concluded that photobiomodulation did not significantly enhance recovery from Achilles rupture beyond the effects of good rehab alone.
This one study isn’t the final word, but it suggests that for major injuries like ruptures, red light therapy may have minimal impact on ultimate outcome. It’s possible that the standard rehab (which in these cases is quite intensive) provides such strong stimulus for healing that the added light doesn’t make a big difference.
💡 That said, if pain relief is a priority in the early weeks, red light could still serve a purpose: as noted, the treated patients had lower pain with walking during rehab, which could potentially make the rehabilitation exercises more tolerable.
Is red light therapy safe?
Red light therapy is generally considered a low-risk treatment when used properly. Unlike UV light, it doesn’t damage skin or cause burns at therapeutic doses. Most studies report no serious side effects.
The main caution is not to overdo it – delivering too high a dose or treating too often can actually slow healing (a phenomenon called the biphasic dose response).
Additionally, you should avoid shining a high-powered red light directly into your eyes (wear eye protection, since devices can be very bright).
People with certain conditions like active cancer or those on photosensitive medications should check with a doctor first, but for the average person with an Achilles injury, red light therapy is a non-invasive, drug-free option with a good safety profile.
The red light therapy devices below are all able to deliver the settings and dosages that are best for Achilles tendon treatment recommended further down.
There are also smaller, hand-held devices available on the market, but I could not find one that states its irradiance (an important aspect of the correct treatment - see below), so I can't recommend one with confidence.
Using red light therapy: best settings for the Achilles tendon
To get the most out of red light therapy for an Achilles injury, you need to use the right type of device and settings. Research and clinical experience suggest the following guidelines for treating tendons like the Achilles:
Wavelength: Use either red light (around 660 nm) or near-infrared (810–830 nm), or a combination. Red light (~660 nm) is effective for more superficial portions of the tendon (since red light penetrates a few millimetres into tissue). Near-infrared (which is invisible but deeper penetrating) can reach thicker or deeper areas of the Achilles. The Achilles tendon, being just under the skin at the back of your ankle, can likely be reached by red light; however, near-infrared might ensure the dose gets right through a thicker tendon. Many modern devices actually emit dual wavelengths (e.g. 660 nm + 850 nm) to cover both bases.
Light intensity (irradiance): Aim for a moderate power output at the skin, roughly in the range of 10 to 30 mW/cm² if possible. This information isn’t always easy to find from device manufacturers, but essentially you don’t need extreme power for therapeutic benefit. Avoid intensities much higher than 50 mW/cm² on the skin, as very high intensity can lead to overtreatment and diminishing returns.
Energy dose: The typical energy dose that has benefited tendon tissue is about 4–10 Joules per square centimetre (J/cm²) per session. Delivering this dose is a function of your device’s irradiance and the exposure time. For example, if your device provides 20 mW/cm² to the Achilles area, using it for about 5-7 minutes will give roughly 6-8 J/cm² (since 20 mW/cm² is 0.02 W/cm², and 0.02 W × 300 seconds = 6 J/cm²).
Frequency of treatment: Tendons heal slowly, so you need repeated treatments over weeks. Clinical protocols that showed positive effects often used 2–3 sessions per week (with at least a day gap between sessions to avoid daily overuse). A typical regimen might last for about 4 to 6 weeks, totalling around 8 to 15 sessions on the injured Achilles.
Device choice: For Achilles tendon use, an LED panel or pad is usually the most practical. Early studies often used medical-grade lasers, but newer research confirms that LEDs can produce comparable benefits for tendon healing. LED devices can cover the Achilles and even some of the calf muscle area at once. Infrared heat lamps, on the other hand, are not true photobiomodulation devices and are not recommended (they just heat the skin rather than providing the specific wavelengths for cellular effects).
🚨 During sessions, you should feel no pain or significant heat. If your device is causing discomfort, something is wrong (either it’s an infrared heat lamp or the intensity is too high).
How we can help
Dealing with an Achilles injury can be frustrating and confusing, especially with so many treatment options out there. At Treat My Achilles, our experienced physiotherapists are here to guide you. We specialize in online consultation for Achilles tendon injuries, which means we can assess your condition via video call and create a personalised rehab plan tailored to your needs.
We’ll help you figure out the right balance of rest and exercise, and advise you on adjuncts like red light therapy if you’re considering them. Our goal is to get you back on your feet as safely and quickly as possible, using evidence-based methods that actually work.
If you’re unsure about what to do next for your Achilles tendinopathy or recovery from a tendon tear, book a video consultation with one of our physios. We’ll gladly assist with a structured program and answer any questions you have – whether it’s about exercise progressions, pain management, or therapies like photobiomodulation. Remember, you don’t have to go it alone. With the right guidance and consistent effort, your Achilles can heal, and you’ll be back to doing what you love.
We're all UK Chartered Physiotherapists with Master’s Degrees related to Sports & Exercise Medicine or at least 10 years' experience in the field. All of us have a wealth of experience working with athletes across a broad variety of sports and ranging from recreationally active people to professional athletes. You can meet the team here.
About the Author
Maryke Louw is a chartered physiotherapist with more than 20 years' experience and a Master’s Degree in Sports Injury Management. Follow her on LinkedIn and ResearchGate.