Red Light Therapy for Injuries: Strains, Sprains and When to Start
Red light therapy for injuries has its best human support for easing pain: a 2024 review of six trials in injured athletes found less pain with light than with comparison treatments. It works as an add-on to first aid and rehab, not a replacement. Below: the reviews, when to start, pulled muscles, swelling, ice, trial settings, braces, warning signs and panel set-up.
Key takeaways
- A 2024 review of 6 randomised trials with 205 injured athletes found less pain with light than with comparison treatments. Morgan, 2024
- A 2006 review of acute soft-tissue injury trials found that people given light were 2.7 times as likely to report improvement. Bjordal, 2006
- In a trial of 40 adults with a grade II ankle sprain, a 627 nm red LED added to first aid lowered pain and swelling more than a switched-off LED. Prianti, 2018
- In rats with injured leg muscle, daily 850 nm LED light lowered inflammation by day 3 and increased new muscle fibres by day 7. de Melo, 2016
- The NHS advises protection, rest, ice, compression and elevation for the first 2 to 3 days with no heat, which is why we suggest starting light from about day 3. NHS
Does red light therapy for injuries help?
For pain, the reviews point to yes: light eased pain after soft-tissue injuries more than placebo or comparison treatments in several pooled analyses. The effect works best at an adequate dose and sits alongside first aid and exercise.
| Review | What it pooled | Main finding |
|---|---|---|
| Morgan, 2024 | 6 randomised trials, 205 injured athletes | Less pain with light (standardised mean difference 1.03) |
| Bjordal, 2006 | 9 trials in acute soft-tissue injury, 609 people | 15 of 18 outcome comparisons favoured light |
| Clijsen, 2017 | 18 studies, 1,462 adults with musculoskeletal pain | Less pain than control, with larger effects at recommended doses |
| Tripodi, 2021 | 17 tendon trials, 835 people | Light plus exercise: pain 1.06 points lower out of 10 than sham plus exercise |
| Alayat, 2024 | 6 ankle sprain trials, 598 people | Less pain on average |
The 2006 review concluded that light "can modulate inflammatory processes in a dose-dependent manner". Bjordal, 2006 The trials that worked treated three or more points with enough energy. In the 2017 review, trials that followed recommended dosing showed larger effects. Clijsen, 2017
Most trials used clinic lasers. One study closer to home use worked with LEDs: a university sports team treated 395 injuries with an 830 nm LED, a mean of 4.3 sessions per injury. Foley, 2016 Among 65 athletes with complete data, return to play averaged 9.6 days, against 19.23 days expected. The comparison was with an expected time rather than a control group. More in our guide for athletes.
Which injuries has red light been studied for: strains, sprains, bruises or tendons?
Studies cover the common soft-tissue injuries: muscle strains, ligament sprains, bruises and tendon overuse. The most human data exist for ankle sprains and tendons, while muscle healing itself has mostly been studied in animals.
- Strain: an overstretched or torn muscle, "also called a pulled muscle". NHS
- Sprain: a stretched or torn ligament, usually at the ankle, wrist, thumb or knee. Our sprained ankle article covers the ankle trials and a day by day plan.
- Bruise: a blow crushes muscle fibres without breaking the skin. AAOS OrthoInfo See red light therapy for bruises.
- Tendon overuse: irritation from repeated small stresses. See red light therapy for tendonitis.
- Broken bone: light comes only after the cast is off and the doctor agrees. See red light therapy for broken bones.
Strains come in three grades: grade I heals in a few weeks, grade II in several weeks to months, and grade III, a complete tear, may need surgery. Cleveland Clinic
How soon after an injury can you use red light therapy?
From about day 3, once first aid has done its job and red flags are ruled out. The first 48 to 72 hours belong to protection, rest, ice, compression and elevation, with no heat.
The NHS advises ice "for up to 20 minutes every 2 to 3 hours" and no heat, alcohol or massage for the first couple of days. NHS Temple Health adds that heat should wait until swelling eases, at around 48 to 72 hours. Temple Health, 2025 A panel feels warm on the skin, so day 3 is the cautious home start, even though some clinic trials began earlier alongside first aid.
| Phase | Standard care | Where light fits |
|---|---|---|
| Days 0 to 2 or 3 | Protect, rest, ice, compress, elevate; no heat, alcohol or massage | No light yet |
| Day 3 to week 2 | Gentle movement as pain allows, pain-free cardio | 10 to 15 minutes per area, 3 to 5 times a week, over intact skin |
| Weeks 2 to 6 | Strength and return-to-activity work, physio if needed | Optional add-on; review after 2 to 3 weeks |
| Still painful after 4 to 6 weeks | See a physiotherapist or doctor | Follow their advice |
This follows the PEACE and LOVE approach: protect the injury for the first few days, then load it as symptoms allow. Dubois, 2019 The NHS notes that most people feel better after about 2 weeks but should avoid running for up to 8 weeks.
Does red light therapy for pulled muscle recovery help a hamstring or calf strain?
In animal studies, light on injured muscle lowered inflammation and helped new fibres and blood vessels form. In people, the clearest benefit is less pain while you rehab, and the exercise programme is what gets you back to sport.
A 2014 review of 17 animal studies found less inflammation and more new blood vessels. Am J Phys Med Rehabil, 2014 In rats, an 850 nm LED "induced a significant reduction in inflammation". de Melo, 2016
Light and exercise together did best in a rat study that gave 780 nm laser just before treadmill training. Adabbo, 2016 After 3 days of rest, the damaged area was 4.4% with light plus exercise, against 23.9% in untreated muscle.
One small hamstring trial found return-to-sport time was similar with or without laser added to rehab. Medeiros, 2020 So the useful way to think about red light therapy for a pulled muscle is comfort during rehab, not a shortcut.
- Hamstring: grade 1 may feel better within a week; grades 2 and 3 can take up to several months. Cleveland Clinic
- Calf: a pulled calf brings sudden pain and trouble standing on tiptoe, and takes weeks to months to recover. Cleveland Clinic
Does red light reduce swelling after a sprain or strain?
It may help early swelling settle alongside first aid. In one ankle trial, a red LED plus first aid reduced swelling more than first aid with a switched-off LED by days 3 and 6.
That trial concluded the LED was "effective for pain and oedema in the initial phase of ankle sprains". Prianti, 2018 Pooled across six ankle trials, the clearest result was for pain. Alayat, 2024
In the 2006 review, 19 of 22 controlled lab studies found less inflammation or oedema with light. Bjordal, 2006 Keep compression and elevation going while swelling is visible.
Ice or red light: which comes first, and can you use both?
Ice comes first, in the first 2 to 3 days, and light comes later as an add-on. In the trials, light was added on top of first aid rather than used instead of it.
Keep ice off bare skin. The PEACE and LOVE authors describe its effect as "mostly analgesic", so its main job is comfort. Dubois, 2019
From about day 3 you can use both on separate occasions. After ice, let the skin return to its normal temperature and feeling before a light session, so you can judge warmth.
What settings and how many sessions did injury studies use?
Most studies used short courses: a few sessions over 1 to 2 weeks for fresh injuries and 2 to 4 weeks for tendons. Wavelengths ran from 627 nm red to 904 nm near-infrared, always on the skin over the injury.
| Study | Injury | Light | Dose | Schedule | Result |
|---|---|---|---|---|---|
| Prianti, 2018 | Grade II ankle sprain, 40 adults | 627 nm red LED | 10 J/cm² | Over 6 days, with first aid | Less pain and swelling than a switched-off LED |
| Foley, 2016 | 395 athlete injuries | 830 nm LED | Not given in the abstract | Mean 4.3 sessions per injury | 9.6 days to return, against 19.23 expected; no control group |
| Bjordal, 2006 | Acute soft-tissue injuries, 9 trials | Mostly 632 to 904 nm lasers | 5.0 to 19.5 J in effective trials, 3 or more points | Outcomes within 7 days | 2.7 times as likely to report improvement |
| de Melo, 2016 (rats) | Injured leg muscle | 850 nm LED | 3.2 J | Daily, up to 7 days | Less inflammation, more new fibres |
| Adabbo, 2016 (rats) | Injured leg muscle | 780 nm laser | 3.8 J/cm² | 5 days, before treadmill training | Damaged area 4.4% against 23.9% |
The pattern carries over: red and near-infrared, moderate doses, and several sessions a week alongside first aid or exercise. Clinic laser joules do not convert into a panel session, because a panel lights a broad area from a distance.
Can you use red light over a brace, bandage, cast or graze?
Light needs bare, intact skin, and a cast, splint or brace should never come off just to use light. Cuts, grazes and stitches must close fully before any light goes over them.
Bandages and tape block most light, as our article on red light through clothes explains. Use light on a braced area only when your doctor or physio agrees the brace can come off briefly.
- Cast or splint: wait until the doctor has removed it for good.
- Metal implants: ask your surgeon first.
- Broken skin: never over an open wound, graze, stitches or pin sites.
Can red light help an old or recurring strain?
Light can sit alongside the strengthening programme that prevents re-injury, but the programme does the main work. Scar tissue is stiffer than healthy muscle and makes re-tearing easier, so graded loading matters most.
PEACE and LOVE points to strong evidence that exercise cuts repeat ankle sprains. Dubois, 2019
For long-standing tendon pain, the 2021 review found the benefit when light was added to exercise. Tripodi, 2021 No side effects were reported in the five studies that checked.
Which injuries need a doctor before you try light?
Get medical help first if you heard a crack, felt a pop with sudden weakness, cannot bear weight, or the limb looks misshapen, numb, blue or cold. Light is for diagnosed, closed soft-tissue injuries that are already settling.
- A&E or 999: you heard a crack, the area has changed shape, it is numb or tingling, or the skin is blue, grey or cold. NHS
- Urgent advice: you cannot put weight on it or walk more than a few steps, or pain, swelling or bruising is severe or getting worse.
- A pop: heard or felt a pop, or you cannot move the muscle. Cleveland Clinic
- Calf swelling: up to 10% of people with a calf pull have a blood clot, which needs checking. Cleveland Clinic
If you take painkillers such as ibuprofen or naproxen, or any other medicine, note that our precautions rule out photosensitising medication, so check with your pharmacist or doctor before using the device. Ask your doctor first if you take blood thinners.
Our precautions also rule the panel out during pregnancy, breastfeeding or when preparing for pregnancy; with epilepsy or seizures triggered by light; with a thyroid condition or thyroid medication; with sunburn on the body in the past 2 weeks; for Fitzpatrick skin types V or VI; and for anyone asleep or unconscious.
How do you use a Kivorla panel on a sprain or strain?
From about day 3, over bare intact skin, set the panel about 6 inches from a joint or 12 inches from a broad muscle, with red and near-infrared channels on, for 10 to 15 minutes, 3 to 5 times a week. Wear the goggles and review after 2 to 3 weeks.
The 9-Spectrum Red Light Therapy Panel carries 480, 590, 630, 660, 670, 810, 830, 850 and 1060 nm, each dimmable from 1 to 100%. Our face mask is shaped for the face, so the panel is the device for limbs and the back.
- Position: hang it on a door or wall with the included door hook, pulley, hanging cables and screws, or stand it upright on the floor. For a shoulder or upper back, hang it at that height on a door or wall.
- Legs: for a hamstring or calf, hang it low or stand it upright and turn the back of the leg toward it; for an ankle, raise the foot with the outer side toward the panel.
- Distance: about 6 inches for an ankle, knee, wrist, elbow, Achilles or calf; about 12 inches for a thigh, hamstring or lower back.
- Channels: 630, 660, 670, 810, 830 and 850 nm on, 1060 nm optional, 480 and 590 nm off; pulse off, for continuous light.
- Timer: 10 to 15 minutes per area, set from the controller. If no time is set, the panel stops at 5 minutes.
- Comfort: goggles on, even for legs, and eyes closed; never look into the panel. Skin should feel warm, never hot, and the surface stays at or below 40°C.
- Log: pain out of 10 and what you can do, such as stairs or walking distance.
The trials used modest doses. To stay gentle, turn the channels down from 100%, use a shorter timer (it starts at 1 minute), or step back from 6 to 12 inches. With reduced feeling, for example from diabetes, start at 12 inches and check warmth with a hand that has normal feeling.
Leave at least 6 hours between 30-minute sessions, and keep up your exercise plan.
Read the precautions before ordering. Under our return and refund policy, returns are accepted within 30 days: an unopened device with its seals intact is refunded less a 10% restocking fee, and an opened device that is undamaged and complete is refunded less 20%. Standard shipping to the US, UK and Germany is free.
Kivorla devices are general wellness devices, not medical devices, and are not intended to treat injuries. See a doctor or physiotherapist for a suspected break, tear or severe swelling, and keep the first aid, brace and rehab plan they advise.