About the research on this page. The studies cited here investigate photobiomodulation (PBM) as a therapeutic modality and the specific wavelengths used in PBM research — not Mito Red Light devices. The wavelengths in our panels were chosen because the peer-reviewed PBM literature supports them. Evidence levels and study counts reflect the broader research base, not studies of our products. See the full methodology note at the bottom of this page.

Red Light Therapy for Hair & Scalp: Clinical Evidence & Research

155 StudiesPhotobiomodulation (PBM) Source-linked

What the research shows

Our evidence rating: Moderate for androgenetic alopecia; limited for other types of hair lossUpdated Reviewed by Alexis Cowan, PhD

For androgenetic alopecia (pattern hair loss), meta-analyses consistently find that low-level laser and LED therapy increases hair density. A 2026 meta-analysis of 37 studies (3,298 patients) found an average gain of 18.6 hairs per square centimeter and thicker hair shafts compared with sham (Alahmadi 2026). A 2025 meta-analysis of 38 studies found density gains after 4 to 26 weeks, with larger effects beyond 20 weeks (Perez 2025). Seven double-blind trials of FDA-cleared home devices found more hair growth than sham in men and women, with both comb and helmet designs (Lueangarun 2021).

Combining light with minoxidil gave more density than minoxidil alone in 7 randomized trials, with no increase in side effects (Mawu 2025). Light therapy is not the strongest option, though: a 2024 network meta-analysis of male pattern hair loss ranked oral 5-alpha reductase inhibitors above photobiomodulation (Gupta 2024), and fractional lasers combined with topical agents outperformed low-level light in the 2026 analysis (Alahmadi 2026).

Based on 155 indexed studies in this category, 58 of them in people. These studies test photobiomodulation in general, not Mito Red Light devices.

Evidence by condition

Number of studies in our database for each condition. Direction and certainty are shown only where a meta-analysis or systematic review reports them; otherwise the row says "not graded".

ConditionHuman randomized trialsAll human studiesDirection of resultsCertainty
Androgenetic alopecia 21 39 More hair density and thicker hair versus sham
Alahmadi 2026 (PMID 42339398); Perez 2025 (PMID 39404126)		 Not graded by authors; consistent across meta-analyses, high heterogeneity
Alopecia areata 1 3 Not graded Not graded
Scarring alopecia & CCCA 0 3 Not graded Not graded

Key studies: Hair & Scalp

The strongest human evidence: systematic reviews and meta-analyses first, then the newest randomized trials. Each card comes straight from our study database and links to the paper.

Meta-analysis

Lasers and Energy-Based Devices in the Treatment of Androgenetic Alopecia: A Systematic Review and Meta-Analysis

et al., Skin Appendage Disord, 2026. PMID 42339398

Key finding (checked against the abstract)37 studies, 3,298 patients with androgenetic alopecia. Low-level light added 18.6 hairs/cm² and 10.6 µm of shaft thickness versus sham; with minoxidil it added 11.8 hairs/cm² over minoxidil alone. Fractional lasers with topical agents performed best.
Population
Meta-analysis
Meta-analysis

Low-Level Laser and LED Therapy in Alopecia: A Systematic Review and Meta-Analysis

et al., Dermatol Surg, 2025. PMID 39404126

Key finding (checked against the abstract)38 studies, 3,098 patients. Hair density rose significantly versus placebo in androgenetic alopecia after under 20 weeks (SMD 1.14) and over 20 weeks (SMD 1.44). Too little data to pool other alopecia types.
Meta-analysis

Comparative efficacy and safety of low-level laser therapy and topical Minoxidil combination vs. topical Minoxidil monotherapy in androgenetic alopecia management: a systematic review and meta-analysis of randomized controlled trials

et al., Lasers Med Sci, 2025. PMID 40826200

Key finding (checked against the abstract)7 randomized trials. Light plus minoxidil increased hair density (+6.6 hairs/cm²), hair diameter and satisfaction (RR 1.71) more than minoxidil alone, with similar side effects.
Population
Human
Meta-analysis

A Systematic Review and Meta-analysis of Randomized Controlled Trials of United States Food and Drug Administration-Approved, Home-use, Low-Level Light/Laser Therapy Devices for Pattern Hair Loss: Device Design and Technology

et al., J Clin Aesthet Dermatol, 2021. PMID 34980962

Key finding (checked against the abstract)7 double-blind randomized trials of FDA-cleared home devices. More hair density than sham (SMD 1.27) in men and women, with comb and helmet devices.
Population
Human
Meta-analysis

Photobiomodulation Therapy With Different Wavebands for Hair Loss: A Systematic Review and Meta-Analysis

et al., Dermatol Surg, 2022. PMID 35510860

Key finding (checked against the abstract)36 studies, 966 patients. Red and infrared light were effective for androgenetic alopecia; infrared and ultraviolet light for alopecia areata.
Meta-analysis

The impact of monotherapies for male androgenetic alopecia: A network meta-analysis study

et al., J Cosmet Dermatol, 2024. PMID 38725143

Key finding (checked against the abstract)Network meta-analysis of 20 monotherapies for male pattern hair loss. Oral dutasteride ranked most effective; oral 5-alpha reductase inhibitors outperformed photobiomodulation and other newer options.

Studies that found no effect

Not every trial is positive. "No effect" means the main outcome did not differ from sham or control. "Mixed" means some outcomes improved but the outcome named here did not differ.

YearStudyDesignResultOutcome with no difference
2025 Photobiomodulation therapy in the prevention of chemotherapy-induced alopecia in breast cancer patients: a randomized controlled trial RCT, n = 29 No effect Preventing chemotherapy hair loss when added to scalp cooling
2025 Comparative efficacy of minoxidil alone versus minoxidil combined with low-level laser therapy in the treatment of androgenic alopecia: a systematic review and meta-analysis Meta-analysis No effect Added benefit over minoxidil alone
2023 Efficacy of Low-Level Laser Therapy in Androgenetic Alopecia - A Randomized Controlled Trial RCT, n = 54 No effect Hair density when added to minoxidil
2021 Efficacy of Minoxidil Combined With Photobiomodulation for the Treatment of Male Androgenetic Alopecia. A Double-Blind Half-Head Controlled Trial RCT, n = 21 No effect Added benefit over topical minoxidil

Latest human studies: Hair & Scalp

The 25 most recent human studies in our database for this category.

YearStudyDesignPopulation
2026 Treatment-Resistant Fibrosing Alopecia in a Pattern Distribution Showing Clinical Improvement With Home Low-Level Light Therapy Case report Human: Case report
2026 675-nm diode laser as an adjuvant treatment for telogen effluvium: case series. Case report, n = 13 Human: 13 participants
2026 Low-level light therapy as a novel treatment for central centrifugal cicatricial alopecia: An interventional cohort study Human study Human: (Brief report)
2025 Photobiomodulation therapy and 5% minoxidil in female pattern hair loss: a case series focusing on hair growth phases over a shorter timeframe Case series, n = 9 Human: 9 patients; case series; 12.5 weeks
2025 Focal resolution of alopecia areata in response to potential smartwatch-mediated photobiomodulation Human study Human: case report
2025 Photobiomodulation therapy in the prevention of chemotherapy-induced alopecia in breast cancer patients: a randomized controlled trial RCT, n = 29 Human: 29 participants; randomized trial; During chemotherapy (avg 12 weeks according to protocol)
2025 Low-level light therapy versus topical 5% minoxidil in the management of androgenetic alopecia in males: A randomised controlled trial RCT, n = 91 Human: 91 participants; comparison study, randomized, sham-controlled; 6 months
2025 Clinical Trial Comparing Three Wavelengths in Photobiomodulation Therapy for Hair Loss RCT, n = 68 Human: 68 participants
2025 Clinical Safety and Efficacy of Dual Wavelength Low-Level Light Therapy in Androgenetic Alopecia: A Double-Blind Randomized Controlled Study RCT, n = 160 Human: 160 participants (only 69 completed ?); randomized trial, double-blind; 26 weeks
2025 Photobiostimulation Therapy (PBST) and Pulsed Electromagnetic Field Therapy (PEMF) in Hair Loss Treatment: Multicentric, Retrospective, Case-Control Study Human study, n = 53 Human: 53 participants (40 completed); observational study; 16 weeks
2024 Red and Green LED Light Therapy: A Comparative Study in Androgenetic Alopecia Human study, n = 17 Human: 17 participants; comparison study, self-controlled; 6 months
2024 The efficacy of light-guiding microneedle patch for stimulating hair growth in androgenetic alopecia RCT, n = 16 Human: 16 participants; comparison study, self-controlled; 24 weeks
2024 Effectiveness of 675-nm Wavelength Laser Therapy in the Treatment of Androgenetic Alopecia Among Indian Patients: Clinical Experimental Study Single-arm study, n = 20 Human: 20 participants; single-arm study; 3-month treatment / 4-month study
2024 Impact of Photobiomodulation on the Quality of Life of Men and Women With Androgenetic Alopecia Single-arm study, n = 85 Human: 85 participants; observational study (single arm); 12 weeks
2024 Novel Application of 1064-nm Picosecond Nd:YAG Laser for Male Androgenetic Alopecia Treatment Single-arm study, n = 5 Human: 5 participants; single-arm study; 3-month treatment -> 1-month follow-up
2024 Comparative efficacy of 2% minoxidil alone against combination of 2% minoxidil and low-level laser therapy in female pattern hair loss-A randomized controlled trial in Chinese females RCT, n = 79 Human: 79 participants; randomized trial; 24 weeks
2023 Assessment of Effects of Low-Level Light Therapy on Scalp Condition and Hair Growth Single-arm study, n = 50 Human: 50 participants; single-arm study; 24 weeks
2023 Use of low-level light therapy in management of central centrifugal cicatricial alopecia: A case series of four patients Case series Human: case series
2023 Photobiomodulation With a Continuous Wave Red Laser (660 nm) as Monotherapy for Adult Alopecia Areata: A Case Presentation Human study Human: case report; 21-day treatment -> 4-month follow-up
2023 Efficacy of Low-Level Laser Therapy in Androgenetic Alopecia - A Randomized Controlled Trial RCT, n = 54 Human: 54 participants; randomized trial; 12-week treatment, 16-week study
2023 Experience of Novelty Laser Therapy Emission with 675 nm Wavelength for the Treatment of Androgenetic Alopecia in Male and Female Patients: A Case Series Study Case series Human: case series
2023 The use of photobiomodulation therapy for the management of chemotherapy-induced alopecia: a randomized, controlled trial (HAIRLASER trial) RCT, n = 32 Human: 32 participants; randomized trial; 12 weeks (after chemotherapy)
2023 The efficacy and safety of the combination of photobiomodulation therapy and pulsed electromagnetic field therapy on androgenetic alopecia RCT, n = 80 Human: 80 participants; randomized trial, double-blind; 20-week treatment / 24-week study
2022 Preliminary Investigation on Micro-Needling with Low-Level LED Therapy and Growth Factors in Hair Loss Related to COVID-19 Single-arm study, n = 10 Human: 10 participants; single-arm trial; 20 weeks
2022 Photobiomodulation Effectiveness in Treating Androgenetic Alopecia Single-arm study, n = 25 Human: 25 participants; single-arm study; 10 weeks

Light parameters used in the trials

Wavelengths reported in our database for the 28 human randomized trials in this category (17 wavelength entries; many database records lack a wavelength, and some trials report more than one). This describes the research; it is not a dosing recommendation.

Wavelength bandTimes used in trials
Red (600-699 nm)13
Blue/green (400-599 nm)4

Most common wavelengths: 650-659 nm, 660-669 nm, 630-639 nm, 620-629 nm, 420-429 nm.

What the evidence does not show

  • That light therapy is the most effective hair loss treatment: oral 5-alpha reductase inhibitors ranked higher for men (Gupta 2024, PMID 38725143), and fractional lasers with topical agents outperformed low-level light (Alahmadi 2026, PMID 42339398).
  • Clear benefit for other types of hair loss: data for scarring alopecia, telogen effluvium and chemotherapy-related loss were too limited to pool (Perez 2025, PMID 39404126).
  • Long-term results in severe hair loss: authors call for longer follow-up (Lueangarun 2021, PMID 34980962).

Frequently asked questions

Does red light therapy regrow hair?

For pattern hair loss, yes, modestly. A 2026 meta-analysis of 37 studies found an average gain of 18.6 hairs per square centimeter versus sham (Alahmadi 2026).

How long until results?

Trials ran 4 to 26 weeks, and density gains were larger after 20 weeks than before (Perez 2025).

Should it be combined with minoxidil?

In 7 randomized trials, light plus minoxidil increased hair density and satisfaction more than minoxidil alone, with no difference in side effects (Mawu 2025).

Does it work for women?

Yes. Trials of FDA-cleared home devices showed more hair growth than sham in both men and women (Lueangarun 2021).

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Browse All Hair & Scalp Studies

All 155 studies in this category from our study database, built on the PBM Research Database by Vladimir Heiskanen.

Search every study across all categories: Open the Full Evidence Explorer →

Methodology & important context

The published research indexed and referenced on this page studies photobiomodulation (PBM) as a therapeutic modality and the specific wavelengths used in those studies — not Mito Red Light devices specifically. The wavelengths used across our panels were chosen because the peer-reviewed PBM literature supports them: this is where published evidence is deepest, where dosing parameters have been characterized in human studies, and where clinical guidelines (such as WALT for inflammation and pain) exist. Mito Red Light has not funded or conducted registered clinical trials on our specific devices, and the study counts referenced here reflect the broader PBM research base — not studies of our products.

Where review authors graded certainty (for example with GRADE), we report their grade; other ratings are Mito’s summary. Study counts reflect peer-reviewed photobiomodulation research drawn from major scientific literature databases, peer-reviewed journals, and other published research repositories. PBM response varies meaningfully by person, tissue, condition, dose, wavelength, and session timing; outcomes reported in the published literature may not be replicable for every user. Mito Red Light devices are not intended to diagnose, treat, cure, or prevent any disease. If you have a medical condition or are under a physician’s care, please consult your healthcare provider before beginning any photobiomodulation regimen.