I enjoyed discussions around the topic of low level laser devices for treating hair loss.
Low-level light therapy (often called LLLT or “photobiomodulation”) is a non-drug option for androgenetic alopecia that uses red light (roughly 620–670 nm) to stimulate hair follicles.
Two recent systematic reviews (one if which was also a meta-analysis) of randomized controlled trials (RCTs) concluded that the home-use devices can meaningfully increase hair density compared with sham (placebo-like) devices.
But how do various types of devices- including laser diode vs LED compare? Nowadays, some devices are based on laser diodes, some LED and some have both!! Let’s review two important recent systematic reviews.
First, some definitions!
Laser vs LED — what do these terms mean?
* Laser (LD = laser diode): emits a highly collimated, narrow-band beam (very “focused” light at a fairly specific wavelength).
* LED (light-emitting diode): emits non-coherent, broader-band light that spreads more.
Biologically, both aim to trigger follicle “energy” pathways: red light is absorbed by cytochrome-c oxidase in mitochondria, increasing ATP/ROS signaling that can promote cellular activity supportive of hair growth.
What the studies show (and which is better)??
Across 7 double-blind RCTs (607 participants), laser therapies improved hair density versus sham with an overall standardized mean difference (SMD) ~1.27.
When trials/devices were grouped by light source (LD vs LED) both reviews found a statistically significant difference favoring laser diodes alone over mixed LED+laser devices:
* LDs alone: SMD 1.52 (95% CI 1.16–1.88)
* LEDs + LDs: SMD 0.85 (95% CI 0.55–1.16) (p=0.043).
Based on current RCT level evidence, laser-diode based devices seem a bit better. That said, these are not perfect head-to-head comparisons, follow-up is generally short (≤26 weeks), and LED-only data are limited
References
1. Lueangarun S et al. J Clin Aesthet Dermatol. 2021;14(11):E64–75.
2. Gentile P, Garcovich S. Facial Plast Surg Aesthet Med. 2024;26(2) #lllt #hairloss #laser #androgeneticalopecia
