Reply to: The use of low-level light for hair growth: Part I

Sirs,

In the recent article by Avram and Rogers (1), they describe a non-blinded study conducted with seven patients of unknown etiology which evaluated the efficacy of low level laser therapy (LLLT) in enhancing hair growth. While the results of this study did not demonstrate an increase in terminal hair counts that was statistically significant, we believe that had this study been conducted in a double-blind manner with a cohort size large enough to judge significance, a different conclusion would have been reached.

We invite your readers to refer to a doubleblind, sham-device, clinical study that was recently published in the journal Clinical Drug Investigation (2). This article reported on the results of a large study conducted in male patients diagnosed with androgenetic alopecia, Norwood-Hamilton Classification of IIa–V. Hair density counts were conducted utilizing macroimaging and computer dot mapping.

The study published in Clinical Drug Investigation by Leavitt et al. (2) was of 6 months' duration with 110 evaluable patients randomized to either a laser phototherapy device (the HairMax LaserComb®) or a sham-controlled device, whereas the Avram/Rogers study (1) reported on only two evaluable patients at 6 months. We do not believe that the results of therapy in those two patients (and without a control group) could have enabled Drs Avram and Rogers to draw statistically significant conclusions on efficacy. It is also easier to understand why there were equivocal results found with global images when only two patients were evaluated.

In contrast to the Avram/Rogers study, it was found by Leavitt et al. that the large number of evaluable patients (who filled out a questionnaire) led to results that showed statistically significant positive differences in hair density versus those patients on the sham device.

In conclusion, while the Avram/Rogers study provided some evidence of efficacy of LLLT, we believe that had they conducted a much larger, longer-term placebo-controlled study, they would have also seen the statistically significant results such as those found by Leavitt et al. We also believe that future well-designed studies will also confirm the results found in the larger reported study (i.e. that LLLT is an effective, well-tolerated, first-line treatment of androgenetic alopecia in males, and not a device that should be reserved for use only when other modalities prove ineffective).