Treatment of androgenetic alopecia with 5-aminolevulinic acid photodynamic therapy: A randomized, placebo-controlled, split-scalp study of efficacy and safety

What the authors concluded

It is needed to be mentioned that the red light treated side also showed a decreased tendency in hair density at 1 week and 12 weeks after the last treatment, which seems to be different from other studies about red light therapy. Recently, low-level light therapy (LLLT) has been applied to promote hair regrowth in AGA patients by its photobiomodulatory effect [17–19]. In those studies, the wave

Devices that emit this wavelength

Matched on wavelength within 15nm, since LED bins vary by roughly that much and a tighter match would be false precision. Where we have an irradiance figure, the session length is the time needed to reach this study's dose of 60 J/cm² at that intensity.

Matching a wavelength is not the same as reproducing a trial. Session times assume the device's published irradiance is accurate at the distance it was measured, which on brand-claim figures is often optimistic. Where a device publishes both a peak and an average we use the average, and where it publishes a falloff curve we use the lowest figure, so these times run long rather than short. Clinical protocols also control for spot size, contact and skin type in ways a home device cannot.