Green Light Therapy: Benefits, Evidence and Safety
Green light therapy uses visible light of about 500 to 565 nm, and its research follows two separate paths: green LEDs shone on the skin for tone and dark spots, and dim green room light seen by the eyes for migraine and pain. Both paths are young, with small studies and promising early results. Below: the studies, how far green reaches into skin, the settings used, eye safety, and what our devices offer.
Key takeaways
- A 2026 systematic review of 13 studies with 668 people found that most favoured green light for pain, while rating the certainty of the evidence as very low. Bain, 2026
- In a 2021 migraine study, people sat 1 to 2 metres from a 525 nm green LED strip at 4 to 100 lux in a dark room for 1 to 2 hours a day over 10 weeks. Martin, 2021
- In mice, removing the cone cells of the retina completely blocked the pain relief from green light, so the effect runs through the eyes. Tang, 2022
- In a 2025 split-face study of 15 healthy women, 505 nm green LED light for 10 minutes, 6 times a week for 8 weeks, lowered melanin readings on the treated side. Mima, 2025
- Oxyhaemoglobin absorbs 540 nm green light about 87 times more strongly than 630 nm red light, which keeps green close to the skin surface. Oregon Medical Laser Center
What is green light therapy?
Green light therapy is light of about 500 to 565 nm, placed on the skin or seen by the eyes, depending on the study. The two uses work in different ways.
Our guide to LED light therapy colours compares green with the other colours.
| Green LED on the skin | Green room light for pain | |
|---|---|---|
| Wavelength | 505 nm in the main study | 525 nm |
| Where the light goes | Onto the face from an LED mask | Into the eyes, from 1 to 2 metres away |
| Studied for | Skin tone and spots | Migraine and fibromyalgia |
The GreenLight laser shares only the name: NICE describes it as a 180 W, 532 nm laser passed through a cystoscope to treat an enlarged prostate. NICE HTG650
What are the green light therapy benefits for skin and dark spots?
The main human study found lower melanin readings and fewer visible spots on the side of the face treated with 505 nm green light. It was small and in healthy women, so it counts as early evidence.
In the 2025 study, 15 healthy women aged 45 to 57 used an LED mask on one side of the face, chosen at random. Mima, 2025 Sessions lasted 10 minutes, 6 times a week, for 8 weeks. Assessors did not know which side had been treated.
On the treated side, the melanin index fell, skin lightness rose and facial imaging counted fewer spots. The course ran "without adverse events". In skin cells, green light also suppressed tyrosinase, the enzyme that drives pigment production.
The study had no sham device, did not report skin type, and four authors worked for a device maker. It looked at healthy skin rather than melasma, so dark patches remain a question for a dermatologist. Our guide to red light therapy for hyperpigmentation covers settings for pigment-prone skin.
How deep does green light reach compared with red and near-infrared?
Green reaches about 1 mm into skin by our estimate, against 2 to 3 mm for red and 5 to 10 mm for near-infrared. The reason is blood: haemoglobin soaks up green light far more strongly than red or near-infrared.
Oregon Medical Laser Center figures for oxyhaemoglobin show the gap. Oregon Medical Laser Center
| Comparison | Green (530 to 540 nm) is absorbed more strongly by |
|---|---|
| Against 630 nm red | About 65 to 87 times |
| Against 660 nm red | About 125 to 167 times |
| Against 850 nm near-infrared | About 38 to 50 times |
These are absorption figures, not a measured depth, but they explain why green acts near the surface while red and near-infrared travel further. See infrared vs red light therapy for the deeper wavelengths.
Green vs red light: which suits wrinkles and firmness?
Red and near-infrared light have the larger body of skin trials, including sham-controlled wrinkle studies. Green light has been studied for tone and spots rather than for wrinkles or firmness.
Our colours guide describes a 76-person double-blind trial in which 633 and 830 nm light, twice a week for 4 weeks, reduced wrinkles by up to 36%.
Cleveland Clinic says red light "may reduce inflammation and stimulate the production of collagen". Cleveland Clinic
Does green light therapy help migraine, and how many hours a day did studies use?
Small studies found fewer headache days with dim green room light for 1 to 2 hours a day over 10 weeks, and a 2025 randomised trial used 1 hour a day, 5 days a week, for 4 weeks. These are studies of light seen by the eyes, not light on the skin.
The University of Arizona study enrolled 29 people with migraine who kept their usual care. Martin, 2021 Each had 10 weeks of white LED light, a 2-week break, then 10 weeks of green.
- Light: a 525 nm LED strip at 4 to 100 lux, 1 to 2 metres from the eyes, in a dark room, for 1 to 2 hours a day.
- Viewing: the strip stayed in view while participants blinked normally and avoided staring at it.
- Result: headache days fell by more than half in 6 of 7 people with episodic migraine and 12 of 19 with chronic migraine.
Pain fell from 8 to 3.2 out of 10 with green, against 8.5 to 7.9 with white. The study was not randomised, white light always came first, and no side effects were reported. One of the researchers stressed, "It's not any green light." University of Arizona
In the 2025 trial, 89 people with migraine were randomised to a 525 nm green lamp, brain stimulation (tDCS) or sham stimulation. Mahmood, 2025 Median pain fell from 4 to 1 with green light and with real stimulation, and from 4 to 3 with sham. It was not blinded.
The best intensity and type of lamp are still unknown, NeurologyLive and Healthline advises talking to a doctor first. Healthline
Why can't a green LED face mask copy the migraine and pain studies?
In animal studies, the pain relief from green light ran through the eyes: blocking the eyes or removing the cone cells of the retina stopped it. The human studies also used dim room light seen from a distance, not LEDs on the face.
In rats with nerve pain, green light raised pain thresholds for 4 days after the last exposure, but rats wearing opaque contact lenses gained no benefit. Ibrahim, 2017
In mice, green light at 10 lux eased pain through a pathway from the retina to brain cells that release enkephalin, one of the body's own opioids. Tang, 2022
In one rodent model only 200 lux worked, while 50 and 500 lux did not. Dai, 2025 The same review notes that short-wavelength light "may not penetrate skin enough" to act on deeper tissue.
During untreated migraine attacks in a 2016 lab study, green was the only colour that lowered headache ratings, by up to 15%. Noseda, 2016 At high intensity, nearly 80% reported worse headaches under every colour except green. ScienceDaily, 2016 Anyone sensitive to light during attacks is better off skipping bright device sessions on those days.
Does green light help fibromyalgia pain and sleep?
A small Arizona study found pain fell from 8.38 to 4.86 out of 10 after 10 weeks of green room light, with little change under white light. Participants also rated falling asleep as easier.
The study analysed 21 people, 20 of them women. Martin, Pain Medicine 2021 They used 525 nm LED strips 1 to 2 metres from the eyes in a dark room, at least 1 hour a day for 10 weeks.
- Pain: 8.38 to 4.86 with green, against 8.7 to 8.1 with white.
- Falling asleep: patient-rated improvement of 51.4% with green, against 11.1% with white.
The design had no randomisation or placebo, and no adverse events were reported. A separate feasibility pilot in 45 people tested green-filtering glasses, and its differences in opioid use were not statistically significant. Nelli, 2023 For light on the skin over sore areas, see red light therapy for fibromyalgia.
How strong is the evidence for green light therapy overall?
It is early and promising: a 2026 systematic review of 13 studies with 668 people found that most favoured green light for pain. It rated the certainty of the evidence as very low and called for blinded, sham-controlled trials.
The review covered 9 randomised and 4 non-randomised studies in migraine, fibromyalgia, dental anxiety, autism and discomfort during eye examinations. Bain, 2026 The authors call green light "promising" and say the evidence is not yet enough to establish that it works.
What settings did the green light studies use?
The room light studies used 525 nm green at 4 to 100 lux, 1 to 2 metres from the eyes, for 1 to 2 hours a day. The skin study used 505 nm LEDs on the face for 10 minutes, 6 times a week, for 8 weeks.
| Study | Studied for | Light | Brightness | Time per day | Sessions | Weeks | Where the light went |
|---|---|---|---|---|---|---|---|
| Martin 2021, Cephalalgia (29 people) | Migraine | 525 nm LED strip | 4 to 100 lux | 1 to 2 hours | Daily | 10 | Seen by the eyes, 1 to 2 m away, dark room |
| Martin 2021, Pain Medicine (21 people) | Fibromyalgia | 525 nm LED strip | About 4 to 100 lux | 1 to 2 hours (average 1.45) | Daily | 10 | Seen by the eyes, dark room |
| Mahmood 2025, Brain Sciences (69 analysed) | Migraine | 525 nm lamp | Not reported | 1 hour | 5 a week | 4 | Seen by the eyes |
| Mima 2025, Acta Derm Venereol (15 people) | Skin tone and spots | 505 nm LED mask | Not reported for the face | 10 minutes | 6 a week | 8 | On the skin, one side of the face |
Is green light therapy safe for your eyes and skin?
Green LEDs give visible light, not ultraviolet, and the Arizona migraine and fibromyalgia studies and the skin study reported no adverse events. The main care point is the eyes: participants did not stare at the light.
Cleveland Clinic says side effects of LED therapy are "rare" and advises eye protection at home, "such as sunglasses or goggles". Cleveland Clinic
- Eyes: never look into any LED device. With our panel, wear the supplied goggles and close your eyes. The mask has an eye opening with no diodes over the eyes; keep your eyes closed.
- Medicines: our precautions rule out use with photosensitising medication, so anyone taking a medicine should check with their pharmacist or doctor before using the device.
- Skin: never on broken skin or an open wound. The panel is also not for use after sunburn on the body in the past 2 weeks.
- Both devices: not during pregnancy, with epilepsy, or with a thyroid condition or thyroid medication.
- Panel only: not while breastfeeding or preparing for pregnancy, with seizures triggered by light, while asleep, or for Fitzpatrick skin types V and VI.
More in our guides to red light therapy goggles and whether red light therapy is safe.
What do Kivorla devices offer if you are interested in green light?
Neither Kivorla device has green light. Both combine red and near-infrared with blue, and the panel also carries a 590 nm amber band.
For the skin side of green light, red and near-infrared reach deeper and have the larger body of skin trials. The mask covers the face; the panel reaches the body, the jawline, under the chin and the neck.
The cordless 4-Wavelength Red Light Therapy Mask runs from the handheld controller or by voice.
- Red mode: 665 nm red with 850 and 1064 nm near-infrared, the mode for even tone and pigment-prone skin.
- Blue mode: 460 nm blue with 850 nm near-infrared, for breakouts, earlier in the day; at 50% if your skin marks easily, and stop if patches darken.
- Settings: brightness 50, 70 or 90%, and a 5, 10 or 15 minute timer that switches the mask off.
- First week: the red mode at 50% brightness for 5 minutes, on clean, dry skin.
- Limits: 10 minutes up to 4 times a week at high brightness, or 15 minutes up to 3 times a week, never more than 20 minutes a day, counting both modes together.
The 9-Spectrum Red Light Therapy Panel carries 480, 590, 630, 660, 670, 810, 830, 850 and 1060 nm, each adjustable from 1 to 100%. Its 590 nm amber band is one of nine wavelengths, and it can be dimmed or switched off on its own. The panel hangs on a door or wall with the included door hook and pulley, or stands upright on the floor.
- Skin tone on the body: 480 nm at its lowest and the other channels started low, 6 to 12 inches away, 10 to 15 minutes per area.
- Sore neck, shoulders or back: red and near-infrared on, 480 and 590 nm off or lowest, continuous light, about 12 inches away. Start at 5 minutes and build to 10 to 15 minutes, 2 to 3 sessions per area a week.
- Near the neck: side-on or from behind, goggles on and eyes closed, never aimed at the face.
- Timer: 1 to 30 minutes on the controller, stopping at 5 minutes if none is set.
For gentler sessions, shorten the timer, dim each channel, or step back from 6 to 12 inches. Use sunscreen after a skin session. Neither device is designed for migraine, so talk to your doctor if green light for headaches interests you.
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 for migraine, fibromyalgia, melasma or any other condition. Talk to a doctor before trying green light for migraine or pain, and see a dermatologist about dark patches or melasma.