Red Light Therapy for Hair Growth and Hair Loss: What the Trials Show
Red light therapy can help hair grow in pattern hair loss, the common inherited thinning seen in men and women. In sham-controlled trials, 16 to 26 weeks of red light on the scalp added roughly 15 to 19 more hairs per square centimetre than a look-alike device, and the hairs grew thicker. Below: the trials, the schedules they used, panel vs cap, minoxidil, and beards.
Does red light therapy work for hair growth?
Yes, for pattern hair loss at an early to moderate stage. Across sham-controlled trials in men and women, red light on the scalp increased both the number of hairs and their thickness.
A 2022 network meta-analysis of 17 placebo-controlled trials found that after 24 weeks, light users had 18.75 more hairs per cm² than placebo in men and 16.62 more in women. Frontiers in Medicine, 2022 Four multicentre trials of laser combs, with 225 people analysed, found a pooled difference of about 15 hairs per cm² over sham. Am J Clin Dermatol, 2014 A 2026 meta-analysis of 37 studies put the gain at 18.56 hairs per cm², with hair shafts 10.62 µm thicker. Skin Appendage Disorders, 2026
| Trial | People | Light and device | Schedule | Result, light vs sham |
|---|---|---|---|---|
| Jimenez 2014, four trials | Men and women | 655 nm (or 635 + 655 nm) laser combs | 8 to 15 min, 3 times a week, 26 weeks | +18.4 to +25.7 vs +1.6 to +9.4 hairs/cm² |
| Kim 2013 | 40 men and women | 630, 650 and 660 nm LED and laser helmet | 18 min daily, 24 weeks | +17.2 hairs/cm² vs a loss of 2.1 |
| Suchonwanit 2019 | 40 men and women | 660 nm laser helmet | 20 min, 3 times a week, 24 weeks | +10.21 vs +3.95 hairs/cm² |
| Lanzafame 2013 | 44 men | 655 nm laser and LED helmet | 25 min every other day, 16 weeks | Hair count +67.2% vs +28.4% |
| Lanzafame 2014 | 47 women | 655 nm laser and LED helmet | 25 min every other day, 16 weeks | Hair count +48.07% vs +11.05% |
Sources: Dermatol Surg, 2013, with its figures as reported by Hamblin, 2019; Lasers Med Sci, 2019; Lasers Surg Med, 2013; Lasers Surg Med, 2014. A Stanford Medicine dermatologist sums it up: "Used over multiple months consistently, red light has been shown to regrow thinning hair." Stanford Medicine, 2025 The American Academy of Dermatology sets the scale: red light can "regrow some hair over time" but "won't regrow a full head of hair". AAD These results come from devices built for the scalp, which is why our overview of red light therapy benefits lists combs and helmets for hair.
How does red light help hair grow?
It acts on the follicle's energy supply and growth cycle. An enzyme in the mitochondria, cytochrome c oxidase, absorbs the light, energy production rises, and more follicles move into anagen, the growing phase.
That mechanism is set out in a 2019 review. Hamblin, 2019 An earlier review adds that the light stimulates stem cells in the follicle bulge, and notes that inherited thinning affects about half of men over 40 and up to 75% of women over 65. Lasers Surg Med, 2014
Which types of hair loss can red light therapy help?
The evidence for red light therapy for hair loss is in androgenetic alopecia, also called male or female pattern hair loss. Other kinds of hair loss have different causes, so see a doctor or dermatologist first to find out which one you have.
The trials enrolled adults of about 18 to 60 with mild to moderate thinning (Norwood IIa to V in men, Ludwig I to II in women) and Fitzpatrick skin types I to IV. Lasers Surg Med, 2014 Starting early, at the first signs of thinning, gives the best chance; a completely bald, shiny scalp has lost its follicles and will not regrow. Hamblin, 2019 A Nebraska Medicine dermatologist says laser caps work on follicles "that are still active". Nebraska Medicine, 2026
- Pattern hair loss: the main body of evidence, in men and women.
- Alopecia areata: autoimmune round patches. Light studies are small, with 50 patients across a 2025 review, and the condition needs a dermatologist. Dermatol Surg, 2025
- Hair loss during cancer treatment: a matter for the oncology team.
- Shedding after illness, stress, weight loss or iron deficiency: often temporary, according to the NHS, so finding the cause comes first. NHS
- Scarring or inflammatory hair loss: Nebraska Medicine says laser caps won't help these.
Does red light therapy work for women's hair loss?
Yes. Women took part in most of the trials, and their gains were close to those seen in men.
In the two comb trials in women, terminal hairs rose by 20.2 and 20.6 per cm² against 2.8 and 3.0 with the sham, and 95% of users gained more than 5 hairs per cm², against 32 to 33% on sham. Am J Clin Dermatol, 2014 Of female pattern hair loss, the AAD says: "A few studies show that this can be effective". AAD
What wavelength is best for hair growth?
Red light at 630 to 660 nm is what most hair trials used, most often 655 nm. Near-infrared shows promise in laboratory work, with fewer clinical trials so far.
In laboratory tests on follicle cells, 660 nm was the most efficient of the LED wavelengths tested (415, 525, 660 and 830 nm), and near-infrared from 760 to over 1000 nm did as well or better in early experiments. Hamblin, 2019 A 2026 guide from the International Society of Hair Restoration Surgery gives a surgeon's view that wavelength matters more than whether the source is a laser or an LED. ISHRS, 2026 The main bands are compared in 660 nm vs 850 nm.
How long does red light therapy take to regrow hair?
Judge it at about four to six months. Gains were measurable at 12 weeks and larger at 24.
In the 2022 network meta-analysis, light users had 12.21 more hairs per cm² than placebo at 12 weeks in men and 9.78 more in women, rising to 18.75 and 16.62 at 24 weeks. Frontiers in Medicine, 2022 In the first comb trial, 83.7% of comb users reported improvement at week 16, against 54.5% with the sham. Am J Clin Dermatol, 2014 As the AAD puts it, "Hair grows slowly, so it takes time to see results." AAD Our guide to how long red light therapy takes to work covers the face and body; for hair, take photos at the start, at month 3 and at month 6, with the same lighting and parting.
A few people notice extra shedding in the first weeks; in one trial it settled within six weeks. Lasers Med Sci, 2019 Lasers used for hair removal are a different thing: high-power pulsed diode lasers at around 800 nm, a different energy class from low-level light. J Cosmet Laser Ther, 2003
How often should you use red light therapy on your scalp?
Three times a week or every other day, for about 10 to 25 minutes, is the pattern most trials used. More is not better: in a 2019 meta-analysis, schedules under 60 minutes a week did better than longer ones.
That meta-analysis pooled 11 double-blind trials and found more hair with light in men and women, with combs and helmets alike. Lasers Med Sci, 2019 The 60-minute cut-off is reported in a later review. Actas Dermo-Sifiliográficas, 2021 Typical home dosing in the research is 630 to 660 nm, about 4 J/cm², for 10 to 20 minutes, daily or every other day. Hamblin, 2019
Does red light therapy for hair have side effects?
Side effects in the hair trials were few and mild, mostly dry skin or itch. The four comb trials reported no serious events.
In those trials, 5.1% of users reported dry skin, 2.5% itch, and 1.3% each scalp tenderness, irritation or warmth. Am J Clin Dermatol, 2014 The 2014 helmet trial in women reported "No adverse events or side effects" Lasers Surg Med, 2014, and a Nebraska Medicine dermatologist describes the risk as low, mainly dryness, itch and warmth. Nebraska Medicine, 2026
Can you use a red light panel for hair growth, or do you need a cap?
Scalp caps, combs and helmets are what the trials used, and they are built for the scalp. A panel emits the same kind of red light and can light the scalp, as long as the hair is parted, the head is held at a steady distance and the goggles are on.
What carries over is the wavelength and a dose you can calculate, provided the light reaches the scalp. The 2019 helmet trial delivered 3.5 mW/cm² at the scalp and 4 J/cm² per session. Lasers Med Sci, 2019 Our panel's red output at 6 inches is at least 150 W/m², or 15 mW/cm². On paper, the red channel alone reaches about 4 J/cm² in roughly 4 to 5 minutes at that distance.
Two things reduce what arrives at the skin. Hair absorbs light, and dark hair absorbs more: the ISHRS guide reports that with "even 2mm of hair", dark hair lets through 32 to 37% less light than lighter hair. ISHRS, 2026 And at 12 inches you get well under half the 6-inch dose. A cap sits at a fixed distance, and a comb's teeth part the hair as it moves. Clin Drug Investig, 2009 With a panel you do both jobs yourself.
How do you use red light therapy on your scalp?
Use it on clean, dry hair, part the hair along the thinning area, and face that area towards the light. Wear the goggles, because a scalp session puts your face close to the panel.
- Clean and dry: no oils, styling products or minoxidil on the scalp during the session.
- Part the hair: make one or two partings across the thinning area. Short hair helps.
- Position: sit with the crown or hairline facing the panel at about 6 inches. A door mount with the pulley lets you lower the panel to head height; see how to set up a red light panel at home.
- Hold steady: keep the same distance for the whole session and set the timer.
- Protect your eyes: "Don't substitute sunglasses for protective goggles," says the AAD. More in red light therapy goggles.
How does red light compare with minoxidil and finasteride?
All three have trial evidence behind them in pattern hair loss. A meta-analysis of randomised trials in men found each one better than placebo.
Its authors concluded that minoxidil, finasteride and low-level light "are effective for promoting hair growth". J Am Acad Dermatol, 2017 Mayo Clinic says minoxidil takes "at least six months" and has to be continued indefinitely Mayo Clinic, and light likewise works only while you keep using it. Many people use light alongside one of the medicines, which is covered next.
Can you use red light therapy with minoxidil?
Yes, and the combination has been studied.
In a 2026 meta-analysis, light plus minoxidil gave 11.75 more hairs per cm² than minoxidil alone. Skin Appendage Disorders, 2026
The individual trials show that the timing varies:
- Faghihi 2018: 50 people used 5% minoxidil with either 785 nm light or an inactive comb. The light group pulled ahead later, with hair count up 78.3% vs 51.3% by month 12. Indian J Dermatol Venereol Leprol, 2018
- Esmat 2017: in women, the combination showed benefit at 2 months, earlier than either alone, as reported by Hamblin, 2019.
- Yang 2024: women using 2% minoxidil with a 655 nm helmet had a greater gain in midscalp hair diameter than with minoxidil alone. Photodiagnosis Photodyn Ther, 2024
The AAD notes that minoxidil "tends to be more effective when used along with another treatment". AAD Hair surgeons also note that light often works better alongside minoxidil or finasteride. ISHRS Do the light session first on a clean scalp and apply minoxidil afterwards, so the liquid is not on the skin under the light. This is general advice, following the same logic as red light before skincare.
What happens if you stop red light therapy for hair?
The gains fade. A Stanford dermatologist puts it directly: "when the person stops applying red light, the effects stop." Stanford Medicine, 2025
The AAD says devices must be used continuously to keep results in female pattern hair loss AAD, and the NHS says hair loss treatments "only work for as long as they're used". NHS So plan a routine you can keep.
Does red light therapy help beard growth?
The trials treated the scalp, so their results do not automatically apply to a beard. The only beard data we found are in patchy, autoimmune hair loss, where a small series using 904 nm infrared laser saw 11 of 12 beard patches regrow.
That series had no comparison group and concerned alopecia areata, not a naturally thin beard. Dermatology Online Journal, 2012 Patches in a beard are a reason to see a dermatologist. If you want to use the panel on the jaw, the face guidance applies: goggles on, eyes closed, 10 to 15 minutes.
How do Kivorla devices fit in?
The 9-Spectrum Red Light Therapy Panel is the Kivorla device that can reach the scalp. It emits red light in the 630 to 660 nm range the hair research used, plus near-infrared.
Its red channels are 630, 660 and 670 nm and its near-infrared channels 810, 830, 850 and 1060 nm, each dimmable from 1 to 100%. At 6 inches, red output is at least 150 W/m² and near-infrared at least 1,200 W/m². The timer runs from 1 to 30 minutes and stops the panel at 5 minutes if no time is set. Suggested use is 10 to 15 minutes per area, with at least 6 hours between 30-minute sessions. Goggles, a controller, a pulley and a door hook come in the box. Our precautions advise against using the panel on Fitzpatrick skin types V and VI. The 4-Wavelength Red Light Therapy Mask covers the face only: its top edge sits at the forehead, so it is not a hair device.
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 hair loss. See a doctor or dermatologist to find the cause of hair loss before starting, and speak to your doctor before combining light with minoxidil or finasteride.