Alopecia Studies Library
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Hair regrowth treatment efficacy and resistance in androgenetic alopecia: A systematic review and continuous Bayesian network meta-analysis
By Feldman
• 2023
• Journal: Front Med (Lausanne)
Abstract:
One Sentence Outcome:
Study Parameters:
Device Parameters: Wavelength: “Some TH regrowth can be expected from most AGA treatments with less variability in women than men. Responses to drug treatments were rapid, showing strong early efficacy followed by the greatest resistance effects from flatlining to loss of regrowth after 12-16 weeks. Finasteride, Minoxidil 2% and Viviscal in men were not statistically different from Placebo. LLLT appeared more efficacious than pharmaceuticals. The natural product formulation ALRV5XR showed better efficacy in all tested parameters without signs of treatment resistance (see Graphical abstract).”
Evidence Level:Systematic review / Meta-analysis
Study Type: Systematic review & network meta-analysis
Outcome Direction: Unclear / review
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The efficacy of light-guiding microneedle patch for stimulating hair growth in androgenetic alopecia
By Charoensuksira
• 2024
• Journal: Arch Dermatol Res
Abstract: “The right side of the scalp was treated with green light and the left with red light” “Both red and green LED treatments with LMNP, significantly enhanced hair density and diameter. Satisfaction scores, as reported by both physicians and participants, increased over time. Comparative analyses revealed no statistically significant differences in average satisfaction scores or in changes in hair density and diameter between the groups by the end of the study. Additionally, no serious adverse effects were reported, highlighting the safety of the treatments. The combined Light sources which is portable LED helmet and LMNPs shows promise as a non-invasive, effective treatment for AGA, with similar efficacy between red and green wavelengths.” Comment: It seems that there was no meaningul difference between red and green light. Since there is no negative control group, we cannot make strong conclusions about either wavelength. Comment: The study claims it was a “randomized” study, but it seems that there was no randomization of treatment arms.
One Sentence Outcome:”The right side of the scalp was treated with green light and the left with red light” “Both red and green LED treatments with LMNP, significantly enhanced hair density and diameter. Satisfaction scores, as reported by both physicians and participants,…
Study Parameters:Sessions: 24 / 24 weeks
Device Parameters: Wavelength: 522 633; Irradiance: 0.050; Fluence: 40
Evidence Level:Evidence review / experimental study
Study Type: Human ⚔ Comparison study, self-controlled 16 participants ⌛ 24 weeks
Outcome Direction: Negative / null
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Clinical Safety and Efficacy of Dual Wavelength Low-Level Light Therapy in Androgenetic Alopecia: A Double-Blind Randomized Controlled Study
By Thomas
• 2024
• Journal: Dermatol Surg
Abstract: “One hundred sixty subjects were randomized. Ninety-one subjects were excluded for the per-protocol analysis.” “Although the primary endpoint (mean change in non-vellus hair count from baseline to week 16) did not reach statistical significance in the individual study arms, in the pooled analysis (combining the 3 active study arms), there was a statistically significant (p = .033) difference versus sham. The pooled study cap group achieved 28.5 more hairs per cm2 when compared with sham.” Comment 1: It seems a lot of participants dropped out, largery due to noncompliance. Comment 2: Queen and Avram published a commentary to the paper: “(…) Interestingly, in this study, both red and blue light wavelengths appeared to show hair growth according to different measures (…)”
One Sentence Outcome:”One hundred sixty subjects were randomized. Ninety-one subjects were excluded for the per-protocol analysis.” “Although the primary endpoint (mean change in non-vellus hair count from baseline to week 16) did not reach statistical significance in the…
Study Parameters:Notes: Blue light
Device Parameters: Wavelength: 625+ 660 425 425+ 625+ 660
Evidence Level:Randomized controlled trial
Study Type: Human Randomized trial, double-blind 160 participants (only 69 completed ?) ⌛ 26 weeks
Outcome Direction: Positive
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Red and Green LED Light Therapy: A Comparative Study in Androgenetic Alopecia
By Tantiyavarong
• 2024
• Journal: Photodermatol Photoimmunol Photomed
Abstract: “Both red and green LED therapies effectively enhanced hair growth, increasing density and thickness over 6 months. Red LED demonstrated superior improvements in specific measures. Consequently, both therapies present safe and viable alternatives for the management of AGA, expanding the repertoire of available treatment options.”
One Sentence Outcome:”Both red and green LED therapies effectively enhanced hair growth, increasing density and thickness over 6 months. Red LED demonstrated superior improvements in specific measures. Consequently, both therapies present safe and viable alternatives for the…
Study Parameters:Time: 1200; Notes: Wavelength comparison
Device Parameters: Wavelength: green red; Fluence: 40
Evidence Level:Preclinical / animal study
Study Type: Human ⚔ Comparison study, self-controlled 17 participants ⌛ 6 months
Outcome Direction: Unclear / review
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Low-level laser therapy accelerates hair regrowth in a mouse model of alopecia
By Wikramanayake TC et al.
• 2012
• Journal: Lasers in Surgery and Medicine
Abstract: Animal study showing stimulation of hair regrowth via PBM in alopecia model.
One Sentence Outcome:Stimulated hair regrowth in alopecia model
Study Parameters:Mouse model
Device Parameters: 655 nm red light; low power ~5–50 mW; animal exposure model
Evidence Level:Moderate
Study Type: Animal Study
Outcome Direction: Positive
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Effect of laser irradiation on hair growth
By Mester E et al.
• 1967
• Journal: Initial experimental reports
Abstract: Early experimental work first demonstrating laser-induced hair growth effects.
One Sentence Outcome:First observation of laser-induced hair growth
Study Parameters:Early experiments
Device Parameters: ~694 nm early ruby laser; low power experimental exposure
Evidence Level:Early
Study Type: Experimental
Outcome Direction: Positive
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Low-level laser therapy for androgenetic alopecia: a review
By Gupta AK, Foley KA
• 2017
• Journal: Dermatologic Surgery
Abstract: Review summarizing consistent positive outcomes of PBM across alopecia studies.
One Sentence Outcome:Consistent positive outcomes across studies
Study Parameters:Review
Device Parameters: 630–660 nm range; typical PBM outputs 5–100 mW; dose dependent
Evidence Level:Moderate
Study Type: Review
Outcome Direction: Positive
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Efficacy of low-level laser therapy in the treatment of androgenetic alopecia
By Jimenez JJ et al.
• 2014
• Journal: American Journal of Clinical Dermatology
Abstract: Randomized controlled trial demonstrating increased terminal hair density in men and women treated with LLLT.
One Sentence Outcome:Increased terminal hair density in men and women
Study Parameters:Randomized, sham-controlled
Device Parameters: 650 nm laser helmet; total output ~100–200 mW; ~5 mW per diode; ~4–6 mW/cm²
Evidence Level:High
Study Type: RCT
Outcome Direction: Positive
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HairMax LaserComb laser phototherapy device in the treatment of male androgenetic alopecia
By Leavitt M et al.
• 2009
• Journal: Clinical Drug Investigation
Abstract: Sham-controlled trial showing statistically significant hair growth with a laser comb device.
One Sentence Outcome:Statistically significant increase in hair growth vs placebo
Study Parameters:Sham-controlled
Device Parameters: 655 nm laser comb; 7–9 beams at ~5 mW each; ~3–5 mW/cm²
Evidence Level:High
Study Type: RCT
Outcome Direction: Positive
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Low-level laser therapy for hair loss: mechanisms and efficacy
By Avci P et al.
• 2014
• Journal: Lasers in Surgery and Medicine
Abstract: Review describing mitochondrial stimulation and hair follicle cycling mechanisms underlying PBM.
One Sentence Outcome:Supports mitochondrial stimulation and hair follicle cycling
Study Parameters:Literature review
Device Parameters: 630–680 nm (typical PBM range); variable power 1–100 mW; dose-dependent
Evidence Level:Moderate
Study Type: Review
Outcome Direction: Positive


