§ Claim under review · Study
"Men with male-pattern hair loss who used 655-nm red-light therapy for 25 minutes every other day for 16 weeks experienced about a 35% increase in hair growth." Accompanying caption adds: "This corresponded to roughly 20 additional hairs per square centimeter of scalp in the measured area."
Verdict
Partially accurate but misleading
Confidence
MediumSummary
This post is built on a real study, but it trims the result in its own favour. The trial is Lanzafame and colleagues, 2013, in Lasers in Surgery and Medicine, and the protocol matches exactly: 655-nm light, 25 minutes, every other day, 16 weeks, 60 sessions, in men with male-pattern hair loss. The paper's main reported result was a 39% increase against a sham device; the 35% figure the post quotes came from a follow-up analysis after removing one placebo participant. Crucially, that percentage is a margin over the placebo group, not a straight personal gain, and the placebo group also grew more hair. The counting was done inside a small tattooed patch of scalp about 2.85 square centimetres, with hairs trimmed before photography, in roughly 40 men over 16 weeks, in a study connected to the device manufacturer. The claim of "roughly 20 additional hairs per square centimetre" does not appear in the paper and does not match the study's own numbers, which work out to about 24 per square centimetre unadjusted or about 12 after subtracting the placebo effect. Red light therapy does have genuine randomized evidence behind it for pattern hair loss, but the effect is modest, short-term, and smaller than this post implies, and the post's purpose is to collect direct messages for a product offer.
The readings
key figures from the evidencepost-hoc hair count increase after excluding placebo outlier
primary all-completers hair count increase vs sham
sham-adjusted hair gain per square centimeter
Why this verdict
Evidence
The study exists and the protocol details in the post match it exactly. The active group received a "TOPHAT655" unit containing 21 five-milliwatt lasers (655 ± 5 nm) and 30 LEDs (655 ± 20 nm) in a bicycle-helmet-like apparatus; the placebo group unit appeared identical but contained incandescent red lights. Patients treated at home every other day for 16 weeks (60 treatments, 67.3 J/cm2 irradiance per 25 minute treatment), with follow up and photography at 16 weeks. A masked 2.85 cm2 photographic area was evaluated by another blinded investigator, and the primary endpoint was the percent increase in hair counts from baseline.
On results: Forty-one patients completed the study (22 active, 19 placebo). No adverse events or side effects were reported. Baseline hair counts were 162.7 ± 95.9 in placebo and 142.0 ± 73.0 in the active group (P = 0.426). Post-treatment hair counts were 162.4 ± 62.5 and 228.7 ± 102.8 respectively (P = 0.0161).
The headline figure was not 35%. A 39% hair increase was demonstrated (28.4 ± 46.2 placebo, N = 19; 67.2 ± 33.4 active, N = 22) (P = 0.001). Deleting one placebo group subject with a very high baseline count and a very large decrease resulted in baseline hair counts of 151.1 ± 81.0 and 142.0 ± 73.0 respectively (P = 0.680); post-treatment hair counts were 158.2 ± 61.5 and 228.7 ± 102.8 (P = 0.011), resulting in a 35% percent increase in hair growth (32.3 ± 44.2 placebo, N = 18; 67.2 ± 33.4 active, N = 22) (P = 0.003).
The stated conclusion was that LLLT of the scalp at 655 nm significantly improved hair counts in males with androgenetic alopecia.
Independent reviews consistently describe the figure as a comparison against sham, not an absolute personal gain: "Increased hair count (by 35% in male patients and 37% in female patients) was observed in the LLLT-treated group versus the sham-treated controls."
Findings
✓ What's accurate 5
- A real randomized, double-blind, sham-controlled trial of 655-nm light in men with androgenetic alopecia exists.
- Every protocol detail in the post is accurate: 655 nm, 25 minutes per session, every other day, 16 weeks, 60 treatments.
- The number 35% does appear in the paper's own abstract, described as a "35% percent increase in hair growth."
- The result was statistically significant (P = 0.003) and no adverse events were reported.
- The finding has been replicated in a companion female trial and is broadly consistent with other LLLT trials showing modest hair density gains.
≈ What's misleading 6
- Omitted qualifier (selective figure): 35% was not the study's primary result. The all-completers analysis produced 39%; the 35% figure comes from a secondary analysis after deleting one placebo participant with an outlier baseline. The post presents the lower, post-hoc number as the finding without noting either the primary analysis or the exclusion.
- Omitted qualifier (comparator removed): the figure is a comparison against a sham device, not a raw personal gain. The placebo group also gained hairs (+32.3 in the target area). The post's phrasing, "men receiving 655-nm red light experienced about a 35% increase," reads as an absolute individual outcome and hides that much of the raw gain occurred in the sham group too.
- Scope overreach: "hair growth" implies the scalp. The measurement was hair counts inside a tattooed 2.85 cm2 patch in the transition zone, with hairs trimmed to 3 mm before photography. This is a research endpoint, not a measure of whole-head cosmetic improvement.
- Unsupported specific number: "roughly 20 additional hairs per square centimeter" does not appear in the study. The correct derivations are approximately 23.6/cm2 unadjusted or approximately 12.2/cm2 after subtracting the sham group. The post's figure sits between the two and is not attributable to the paper.
- Omitted context (funding and scale): a small single-device trial, 40 analysed participants, 16 weeks, sponsored by and authored in connection with the device manufacturer. None of this appears in the post.
- Marketing framing: the study is used as the hook for a lead-generation offer ("comment 'guide'... full hair loss protocol + complete stack"). The before and after scalp images are presented as visual evidence with no indication they came from the trial.
? What's uncertain 4
- Exactly how the authors computed "35%" is not clear from the abstract. The value is numerically almost identical to the raw difference in mean hair count change between groups (67.2 minus 32.3 equals 34.9 hairs), as is the 39% figure (67.2 minus 28.4 equals 38.8). Whether this is coincidence or a labelling issue cannot be resolved without the full text, which I did not retrieve.
- The provenance of the post's before and after images is unverified. I found no evidence they are the study's published photographs.
- The precise funding and conflict-of-interest statement for the 2013 male paper was not retrieved in full. The disclosure is confirmed for the 2014 companion paper using the same device, and the device manufacturer link for the 2013 trial is confirmed through trade coverage.
- Whether the effect persists, plateaus, or reverses beyond 16 weeks is not addressed by this trial.
Sources
6 of 6 linked to recordsLanzafame RJ, Blanche RR, Bodian AB, Chiacchierini RP, Fernandez-Obregon A, Kazmirek ER. "The growth of human scalp hair mediated by visible red light laser and LED sources in males." Lasers in Surgery and Medicine 2013;45(8):487-495
Lanzafame et al. 2014, companion female trial, same device and protocol, Lasers Surg Med
Systematic review and meta-analysis of FDA-cleared home-use LLLT devices, J Clin Aesthet Dermatol
Efficacy of LLLT in Androgenetic Alopecia RCT (comparison table citing Lanzafame 2013)
"Low-level light therapy using a helmet-type device," Medicine (Baltimore) 2020
Laser Focus World report on the trial and the iGrow device