Red Light Therapy for Circulation: What Blood Flow Studies Show
Red light therapy for circulation has a clear, measurable effect in one place: the skin and tissue under the light, where small human studies recorded blood flow rising by 27 to 54% during and shortly after a session. The rise is local and lasts minutes to hours, so regular short sessions make more sense than long ones. Below: the study numbers, how nitric oxide fits in, red versus near-infrared, cold hands, diabetic feet, leg arteries and veins, and panel settings.
Key takeaways
- In a 2020 randomised study of 20 healthy adults, 5 minutes of 830 nm near-infrared light over the wrist raised blood flow in the palm by 27% during exposure and by 54% over the next 20 minutes. Gavish, 2020
- In 24 people with type 2 diabetes, 5 minutes of light on the forefoot raised local blood flow by 41 to 47% at its peak 30 minutes later, and the rise was gone by 24 hours. Samoilova, 2008
- In a placebo-controlled study of 15 healthy adults, near-infrared light on the forearm raised nitric oxide in blood leaving the treated area, with a peak at 5 minutes. Mitchell and Mack, 2013
- A 2021 systematic review of 50 studies concluded that "PBM can modulate endothelial dysfunction, improving inflammation, angiogenesis, and vasodilatation", where PBM means red and near-infrared light. Colombo, 2021
- A randomised home trial of 670 nm red light in 32 people with leg artery disease gives 10 minutes twice daily for four months, with walking distance as the main result. LIGHT PAD trial
Does red light therapy for circulation work?
Yes, locally and for a short time: red and near-infrared light raise blood flow in the area under the light during and shortly after a session. The measured effect is in the treated area rather than the whole body, so think of it as a local boost.
Four small human studies measured flow or skin temperature directly.
| Study | Who | Light and session | What changed |
|---|---|---|---|
| Gavish, 2020 | 20 healthy adults, wrist | 830 nm, 5 minutes | Palm blood flow up 27% during, 54% over the next 20 minutes |
| Mak and Cheing, 2012 | 30 healthy adults, foot | 890 nm LED pads on the skin, 30 minutes | Faster capillary blood flow than with sham light or a warm pack |
| Samoilova, 2008 | 24 people with type 2 diabetes, forefoot | Visible light lamp, with or without near-infrared, 5 minutes | Foot blood flow up 31 to 39% at 2 minutes and 41 to 47% at 30 minutes |
| Schindl, 1998 | 30 people with diabetic small vessel disease, forefoot | Low-intensity laser, one session | Skin temperature rose; it fell slightly with sham |
Sources: Gavish, 2020; Mak and Cheing, 2012; Samoilova, 2008; Schindl, 1998.
The 890 nm pads beat a warm pack as well as sham light, so the effect is more than heat. Cleveland Clinic lists "Increase blood circulation to the tissue" among the ways red light is thought to work. Cleveland Clinic
So red light therapy for blood flow works as a local rise after each session.
How long does the blood flow boost last after a session?
Minutes to hours. In the diabetic foot study, flow peaked at 30 minutes and had returned to normal by 24 hours.
- 20 minutes: palm flow was still 54% higher over the 20 minutes after a 5-minute session. Gavish, 2020
- 5 minutes: nitric oxide in blood leaving the treated forearm peaked at 5 minutes, then slowly declined. Mitchell and Mack, 2013
- 30 minutes, in mice: "the blood flow remained elevated 30 min after termination of the light exposure". Keszler, 2022
In the same mouse study, repeated 670 nm sessions over 14 days raised flow each time in a leg with a narrowed artery, and the leg approached normal levels. Human trials of repeated sessions are running.
How does red light increase blood flow?
The leading explanation is nitric oxide, a gas that relaxes the walls of blood vessels. Light appears to release nitric oxide already stored in the vessel lining, so vessels widen within minutes.
In people, the researchers measuring the forearm wrote: "LLLT increased NO levels in venous blood draining from the treatment site." Mitchell and Mack, 2013
Lab work at 670 nm fills in the detail:
- Released, not made: in mice, a nitric oxide carrier in the blood rose about 50% straight after light, while stores in the lit thigh muscle fell from 123 to 90 pmol/g. Keszler, 2022
- Tiny parcels from the vessel lining: fluid from light-exposed vessel lining cells relaxed isolated arteries by 14.7% of their maximum, against 0.6% for fluid from unlit cells. Keszler, 2024
- A mild signal: a follow-up found that a small, light-induced oxidative signal is part of the process, and that antioxidants added in the lab reduced it. Keszler, 2024
The 2021 review counted nine human studies among its 50. Colombo, 2021 The lab findings line up with the human flow results.
Is red or near-infrared light better for blood flow?
Near-infrared has the clearer human result: in the one study that compared them, 830 nm raised palm blood flow. Red light at 670 nm has the stronger lab evidence on how vessels relax, so a panel with both covers both lines of research.
In that wrist study, 633 nm red light did not change median flow over the same 5 minutes. Gavish, 2020
Depth plays a part. Red light at 660 nm is absorbed in the first few millimetres of skin, while 850 nm reaches roughly 5 to 10 mm. Our guide to 660 nm vs 850 nm explains the difference.
Can red light help cold hands, cold feet or Raynaud's?
Near-infrared light warms the skin slightly during a session, which many people find comfortable. Responses vary: in the wrist study, 10 of 20 volunteers showed a clear response, and those whose hands started very cold or very hot changed least.
The people who responded started with skin at 33 to 37.5°C, and their palm flow rose within about 2.5 minutes. Hands at 33°C or below responded little. Gavish, 2020 So if your hands are icy, warm them the usual ways first.
The NHS self-care advice for Raynaud's: keep warm, "exercise regularly", "do not smoke" and cut down on caffeine. NHS
Fingers that turn white or blue in the cold may be Raynaud's. Two older sham-controlled laser trials reported fewer, milder attacks, and in one, finger rewarming after a cold challenge improved only with laser. al-Awami, 2004 Our article on red light therapy for hands and feet covers these trials.
During an attack, Mayo Clinic suggests running warm, not hot, water over fingers and toes. Mayo Clinic The NHS says to see a GP if symptoms are severe, worsening, one-sided, or start after age 30.
Does red light improve blood flow in numb or diabetic feet?
Two small studies in people with diabetes found warmer skin or higher foot blood flow after a single session. For numb feet, the main practical point is heat safety, because reduced feeling makes it harder to notice skin getting too warm.
In 30 people with diabetic small vessel disease, one laser session at 30 J/cm² raised forefoot skin temperature during the session and 15 minutes after, while it fell slightly with sham. Schindl, 1998 In 24 people with type 2 diabetes, foot flow peaked 41 to 47% higher at 30 minutes. Samoilova, 2008
Heat matters more than light here. Near-infrared pads placed on the calf for 30 minutes raised skin temperature about 9.5°C, to roughly 40°C, which the authors judged safe for healthy people. Mitchell, 2012 A panel at a distance, with a timer, is the gentler setup.
An NHS diabetes foot leaflet says: "Never sit with your feet in front of the fire" and "test the temperature of the water with your elbow". Royal Devon NHS It also asks you to check your feet daily.
Never shine light over an ulcer, a blister or broken skin: our precautions rule out use over open wounds. Once the skin has closed and your foot team agrees, light can be used on that area again. For nerve symptoms, see red light therapy for neuropathy.
Is red light therapy safe with leg pain on walking or peripheral arterial disease?
Leg pain on walking that eases with rest can be peripheral arterial disease, which needs a GP's assessment before any home device. Two 670 nm trials in people with the condition are under way, and their results are not yet published.
The NHS describes fatty deposits that restrict blood supply to the leg muscles. NHS NICE advises supervised exercise, for example "2 hours of supervised exercise a week for a 3-month period". NICE
- LIGHT PAD: 32 people aged 50 and over, 670 nm at home, 26.3 mW/cm², 10 minutes twice daily to the lower legs for four months, against sham light, measuring walking distance. LIGHT PAD trial
- Calf blood flow study: 40 people, one 5-minute 670 nm session 1 cm above the calf, with blood flow measured by ultrasound. University of Alabama trial
For burning leg pain at rest, cold, pale or numb skin, or wounds that do not heal, the NHS says to contact a GP immediately or call 111. If you have the condition, ask your vascular team before using any home device on your legs.
Does red light therapy help varicose veins or spider veins?
No: light on the skin does not close a vein that lets blood flow backwards. The laser treatment the NHS describes for varicose veins is a different procedure, with a fibre placed inside the vein under local anaesthetic.
The NHS calls varicose veins "not usually serious". Its self-care list includes exercise, raising your legs and not standing for long periods. NHS Compression stockings are an option, but not if you have artery problems.
See a GP if veins are painful or a sore has not healed after 2 weeks. For puffy legs, our guide to red light therapy for lymphatic drainage covers swelling.
Can you use red light with blood pressure medicine, blood thinners or a suspected clot?
Keep taking any prescribed medicine: a 2025 review rated the evidence on light and blood pressure as very low certainty. With a suspected clot, such as one warm, swollen, painful calf, do not use light and get urgent medical advice.
The review pooled four randomised trials, which reported lower blood pressure but were at high risk of bias. Espósito, 2025 Light is no substitute for blood pressure medicine.
If you take blood thinners, ask your prescriber before starting. Our precautions also rule out use with photosensitising medication, so anyone taking a medicine should check with their pharmacist or doctor first.
Cleveland Clinic notes that poor circulation "won't get better on its own". Cleveland Clinic The panel is also not for use if you are pregnant, breastfeeding or preparing for pregnancy, with a thyroid condition or thyroid medication, with light-triggered seizures, after sunburn on the body in the past 2 weeks, or with Fitzpatrick skin types V or VI. See is red light therapy safe for more.
What settings did the blood flow studies use?
Single sessions of 5 to 30 minutes at 40 to 60 mW/cm², with flow measured over the next half hour. The leg artery trial gives 10 minutes twice daily for four months.
| Study | Light | Output | Minutes | Sessions | Weeks |
|---|---|---|---|---|---|
| Gavish, 2020 | 830 nm | 55 mW/cm² | 5 | 1 | Single session |
| Mak and Cheing, 2012 | 890 nm LED pads | 60 mW/cm² | 30 | 1 | Single session |
| Samoilova, 2008 | Visible lamp, with or without near-infrared | 40 mW/cm² | 5 | 1 | Single session |
| LIGHT PAD (running) | 670 nm home device | 26.3 mW/cm² | 10 | Twice daily | About 16 |
| Keszler, 2022 (mice) | 670 nm LED | 50 mW/cm² | 5 to 10 | Repeated | 2 |
What carries over to home use is the pattern: short sessions, repeated regularly, because each one raises local flow for minutes to hours.
How do you use a Kivorla panel for circulation?
Set the panel 12 inches from broad areas such as calves, thighs or the lower back, or 6 inches from hands and feet, with goggles on. Run 10 to 15 minutes per area, two to three times a week, for 3 to 6 weeks before judging.
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%. Its 830 and 670 nm channels match the wavelengths in the studies above. At 6 inches it puts out at least 1,567 W/m².
- 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 feet and lower legs.
- Channels: 660, 670, 810, 830 and 850 nm on; 630 and 1060 nm optional; 480 and 590 nm at their lowest setting.
- Hands and feet: about 6 inches, palms then backs, soles then tops, held in front of the panel and never resting on it.
- Numb feet: start at 12 inches, check your skin by eye before and after, test warmth with a hand that has normal feeling, and stay awake.
- Feel: warm, not hot. The surface stays at or below 40°C, but if skin feels hot, stop and step back.
- Timer: 10 to 15 minutes per area. If no time is set, the panel stops at 5 minutes.
The studies used short sessions at modest output. To stay near that range:
- Shorter timer: it starts at 1 minute.
- Dimmer channels: turn near-infrared and red down from 100%.
- More distance: step back to 12 inches.
More is not better. Leave at least 6 hours between 30-minute sessions. Goggles and a controller are included.
Standard shipping to the US, UK and Germany is free. 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%.
Kivorla devices are general wellness devices, not medical devices, and are not intended to treat poor circulation, Raynaud's, peripheral arterial disease, varicose veins or any other condition. See a doctor for leg pain on walking, cold, pale feet, a wound that will not heal or one swollen, painful calf, and keep taking prescribed medicine.