Red Light Therapy for Scalp: Thinning Hair, Psoriasis and Dandruff
Red light therapy for scalp thinning has its clearest support in pattern hair loss: sham-controlled trials of home caps, helmets and combs at 630 to 660 nm found more hairs per square centimetre after 16 to 26 weeks. For scalp psoriasis and dandruff, the light treatment a dermatologist gives is UV, and red light fits as an add-on to that care. Below: the trials, hair as a barrier, psoriasis, dandruff, itch, transplants, safety and panel set-up.
Key takeaways
- In four sham-controlled laser comb trials of men and women, men gained 18.4 to 25.7 terminal hairs/cm² over 26 weeks, against 1.6 to 9.4 with sham. Jimenez, 2014
- A 2022 network meta-analysis found laser combs gave 18.75 more terminal hairs/cm² than placebo in men and 16.62 more in women at 24 weeks. Feldman, 2022
- Between 52 and 80 percent of people with psoriasis have had psoriasis on the scalp. National Psoriasis Foundation
- The light treatment dermatologists use for stubborn scalp psoriasis is UV, such as an excimer laser given in clinic two or three times a week. AAD
- In one comparison, 2 mm of hair cut the light reaching the scalp by 32 to 37%. ISHRS, 2026
Does red light therapy for scalp hair loss work?
For pattern hair loss, the trials point to yes: home caps, helmets and combs produced more and thicker hairs than sham devices after about six months. It thickens thinning areas rather than restoring lost hair, and the AAD says it "won't regrow a full head of hair".
| Study | Who | Device and light | Result against sham |
|---|---|---|---|
| Jimenez, 2014 | 4 trials, 225 people | Laser comb, 655 nm or 635 + 655 nm | Women +20.2 and +20.6 hairs/cm² vs +2.8 and +3.0 at 26 weeks |
| Suchonwanit, 2019 | 40 adults | Laser helmet, 660 nm | +10.21 vs +3.95 hairs/cm² at 24 weeks |
| Kim, 2013 | 40 adults | Helmet, 630, 650 and 660 nm | Greater density and diameter at 24 weeks |
| Lueangarun, 2021 | 7 double-blind trials | Helmets, caps, headbands, combs | Pooled hair density favoured the devices |
The 660 nm helmet also made hair shafts 6.11 micrometres thicker, against 3.76 with sham. Suchonwanit, 2019 A review of 10 randomised trials found every sham-controlled study reported significant gains in hair density or diameter. Egger, 2020 The seven-trial meta-analysis found pooled density clearly favoured the home devices. Lueangarun, 2021
A Stanford dermatologist says consistent use over months "has been shown to regrow thinning hair". Stanford Medicine, 2025 Responses vary from person to person. ISHRS Our guide to red light therapy for hair growth covers the full trial list and pairing light with minoxidil.
Does red light get through hair to reach the scalp?
Partly: hair absorbs and scatters light, so less reaches the skin under a full head of hair. Thinning areas let more light through, and those are the areas that need it most.
A 2019 review calls thick, dark hair "a considerable barrier", and notes that combs help because their teeth part the hair. Hamblin, 2019 A hair surgeon writing for the ISHRS reports that, in one comparison, 2 mm of hair reduced light transmission by 32 to 37%. ISHRS, 2026
- Part the hair: one or two partings along the thinning area so the scalp shows.
- Keep it short: shorter hair leaves less in the way.
- Start clean and dry: no oils, styling products, creams or minoxidil on the scalp during the session.
Can a panel do the job of a cap or comb on the scalp?
The closest evidence comes from caps, helmets and combs worn on or moved over the head, not from panels at a distance. A panel uses the same red and near-infrared bands, and lowering it to head level with the hair parted brings the set-up close to those trials.
A panel covers a broad area from a few inches away, so it lights the crown and one side of the head together, hands free. A face mask cannot stand in: ours is a full-face shell with an eye opening, so it does not reach the scalp. Our mask vs panel comparison explains which device suits which area.
What settings did scalp light trials use, and how long do results take?
Hair trials used 630 to 660 nm red, some adding 808 nm near-infrared, for 8 to 30 minutes, two to seven times a week, over 16 to 26 weeks. Results were judged at four to six months, and they last only while use continues.
| Study | Wavelength | Minutes | Sessions a week | Weeks |
|---|---|---|---|---|
| Jimenez, 2014 (comb) | 655 nm, or 635 + 655 nm | 8, 11 or 15 | 3 | 26 |
| Suchonwanit, 2019 (helmet) | 660 nm | 20 | 3 | 24 |
| Kim, 2013 (helmet) | 630, 650, 660 nm | 18 | 7 | 24 |
| Hamblin, 2019 (review) | 630 to 660 nm, some 808 nm | 15 to 25 | 2 to 7 | 16 to 26 |
| Martinez-Pizarro, 2021 (review) | 630 to 808 nm | 20 to 30 | 2 to 3 | 17 to 24 |
The trial devices sat on the head or moved through the hair. The 2019 review gives about 4 J/cm² as a frequently quoted dose. Hamblin, 2019 A 2021 review reports that schedules under 60 minutes a week appeared more effective than longer ones. Martinez-Pizarro, 2021
The ISHRS writer says scalp hair takes 11 to 12 months to fully respond.
Does red light therapy for scalp psoriasis help?
Red light is an add-on here, not a first treatment: the closest evidence comes from body plaques, where red and near-infrared LEDs cleared 60 to 100% of treated sites in a small pilot. Scalp psoriasis care starts with prescribed treatments, and red light therapy for scalp psoriasis belongs alongside them, with your dermatologist's agreement.
The pilot treated 9 people with stubborn body psoriasis, using 830 nm and then 633 nm LED light for 20 minutes, twice a week for 4 to 5 weeks, with no control group. Ablon, 2018 NICE sets out the usual order of scalp treatment: NICE CG153
- First: a potent corticosteroid once a day for up to 4 weeks.
- Next: a medicated shampoo or mousse, and descaling agents such as salicylic acid, emollients and oils.
- Then: a calcipotriol and betamethasone combination, or vitamin D.
- If still active: a very potent corticosteroid, coal tar, or a specialist.
Hair blocks much of the light, so a panel reaches plaques best on bare skin: the hairline, behind the ears, the nape of the neck and along a parting. See red light therapy for psoriasis for plaques on the body.
Never shine light on cracked, bleeding, picked or scratched plaques: "scratching or wounding of the skin can worsen psoriasis". National Psoriasis Foundation
Coal tar can make skin more sensitive to sunlight, and psoralen makes skin and eyes sensitive to light for 12 hours. Newcastle Hospitals NHS Leeds Teaching Hospitals NHS Our precautions rule out use with photosensitising medication, so if you use any medicated scalp treatment, check with your pharmacist or doctor before using the panel. If you already have UV treatment, tell the phototherapy team before adding a home light. Psoriasis UK, 2018
Is red light the same as the light dermatologists use for scalp psoriasis?
No: the light treatment dermatologists prescribe for scalp psoriasis is ultraviolet, such as narrowband UVB, a 308 nm excimer laser or a handheld UV comb. Red and near-infrared LEDs give out no UV, so they work by a different route.
The AAD describes excimer sessions of about 10 minutes, two or three times a week, for several weeks.
In a 2021 trial of 30 people with scalp psoriasis, a 308 nm excimer lamp was given twice a week, alone or with a coal tar solution. Rattanakaemakorn, 2021 A 75% improvement was reached by 28.6% with the lamp alone and 69.2% with tar added. That result belongs to UV; red light sits beside prescribed care rather than in place of it.
Can red light help dandruff or seborrheic dermatitis on the scalp?
The evidence is early and indirect: in the lab, red and blue light slowed Malassezia, the yeast group linked to dandruff, and on the face, red light added to a prescription cream improved seborrheic dermatitis. Medicated shampoo stays the first step, with light as an add-on.
- Lab work: 625 nm red and 465 nm blue light each slowed Malassezia yeast taken from dogs, with blue the stronger. Kim, 2018
- Face trial: in 201 people, red light added to tacrolimus cream for 8 weeks improved signs and symptoms. Fang, 2023
The AAD advises dandruff shampoo 2 to 3 times a week for straight or wavy hair, and once a week for curly or coily hair. AAD Some shampoos need to stay on for 5 to 10 minutes, and the coal tar note above applies to tar shampoos too. AAD, dandruff
Heat can trigger seborrheic dermatitis, so keep sessions warm, never hot. See red light therapy for seborrheic dermatitis for the face and eyebrows.
What should you rule out before using light on an itchy scalp?
Find the cause first, because scalp itch can come from dandruff, a reaction to hair dye, lice, scabies, ringworm, psoriasis, eczema, nerve problems or, rarely, skin cancer. Lice, scabies and ringworm need their own treatment, and a dermatologist can help when the cause is unclear.
The AAD notes that "Scalp psoriasis is often itchy, with the itch ranging from mild to intense." AAD, itchy scalp A Cleveland Clinic hair specialist names seborrheic dermatitis as the most common cause, and advises a dermatologist if itch keeps returning or comes with hair loss, a rash or pain. Cleveland Clinic
If a session leaves your scalp itchy, shorten it and step back.
Can you use red light on the scalp after a hair transplant?
Only once your surgeon agrees and the grafted and donor areas have healed, and never over open grafts, scabs, stitches or the donor wound. Some hair surgeons use light in their own clinics after surgery, so ask yours what fits your recovery plan.
The ISHRS notes that some physicians report light may enhance growth and reduce inflammation after transplantation. ISHRS Research is early: one small 2016 study shone light on grafts before implanting, not on the healing scalp. Tabaie, 2016
Who should see a doctor first, and who should not use the panel?
See a GP or dermatologist first for sudden, patchy, scarring or painful hair loss, or hair loss with a rash. Do not use the panel if you are pregnant, take photosensitising medication or have Fitzpatrick skin type V or VI, among the other precautions below.
Losing 50 to 100 hairs a day is normal, and illness, stress, weight loss and iron deficiency can cause temporary loss. NHS People with scarring or inflammatory hair loss "will not see benefits from these devices". Nebraska Medicine, 2026 Fully bald areas are also unlikely to respond.
- Pregnancy: while pregnant, breastfeeding or preparing for pregnancy.
- Seizures: epilepsy or seizures triggered by light.
- Thyroid: a thyroid condition or thyroid medication.
- Skin: broken skin on the area, sunburn on the body in the past 2 weeks, or Fitzpatrick skin type V or VI.
- Sleep: not for use while asleep or by anyone unconscious.
Side effects in the comb trials were mild: dry skin in 5.1%, and tenderness, irritation and warmth in 1.3% each. Jimenez, 2014 In the helmet trial, one woman had extra shedding at 2 weeks that settled within 6 weeks.
How do you use a Kivorla panel on your scalp?
Hang the panel at head level, put the goggles on, close your eyes and turn the side or back of your head toward it at about 6 inches, with the hair parted. Run the red and near-infrared channels for 10 to 15 minutes per area, about three times a week or every other day, and judge thinning hair at four to six months.
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 red and near-infrared channels sit close to the bands in the hair trials.
- Position: hang it on a door or wall with the included door hook, pulley, hanging cables and screws, lowered to head height as you sit, or stand it upright on the floor.
- Aim: turn the crown, the side or the back of your head toward the panel. For the hairline, tilt your chin down so the top of your head faces it. Your face never faces the panel.
- Eyes: goggles on before the panel switches on until the timer stops, eyes closed, never looking into the panel. See red light therapy goggles.
- Distance: about 6 inches for a small thinning patch, up to 12 inches for a broader area or if it feels warm.
- Channels: red and near-infrared on; 480, 590 and 1060 nm at their lowest; continuous light, as in the trials.
- Timer: 10 to 15 minutes per area. If no time is set, the panel stops at 5 minutes. The surface stays at or below 40°C.
- Order: light first on a clean scalp, then minoxidil or your prescribed treatment; your prescriber has the final say.
- Log: photos at the start, month 3 and month 6, in the same light and parting. For psoriasis or dandruff, keep settings the same for 8 weeks and compare.
The hair trials used low-power caps and combs. To stay near that range, start with a short timer (it starts at 1 minute) and the channels turned down from 100%, or step back to 12 inches, then build up. One area at 10 to 15 minutes three times a week stays under 60 minutes a week. If your scalp feels hot, lower the near-infrared first.
Leave at least 6 hours between 30-minute sessions. Our guide to setting up a red light panel at home covers hanging height.
Read the precautions before ordering. Standard shipping to the US, UK and Germany is free. 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 hair loss, psoriasis or any scalp condition. See a GP or dermatologist for sudden or patchy hair loss, a scalp rash that will not settle, or before adding light to prescribed scalp treatment.