How does RLT help?
Red/NIR light (RLT) has proven to help both men and women with a wide variety of conditions to prevent hair loss and even regrow hair. Not only that, but RLT can also increase the thickness of each hair strand. Thus, red light therapy can help improve both the quality AND quantity of your hair!
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Male and female pattern hair loss (PHL) is a common, chronic dermatologic disorder. Male PHL (aka, androgenetic alopecia) affects 50 % of men by 50 years of age and the frequency and severity increases with age. Male or female PHL may be accompanied by psychosocial consequences including decreased quality of life and poorer body image. Hair follicle atrophy caused by aging is a common type of hair loss.
To better understand how RLT can help prevent hair loss and promote hair regrowth, it helps to understand the three main phases of hair growth:
Anagen - growth phase
Catagen - transition of hair upwards towards skin pore
Telogen - the blood supply to the hair follicle fully separates, growth ends
Red and near-infrared light apparently promotes the transition of hair follicles from the telogen phase back to the anagen phase, which facilitates increased duration in the growth phase and, thus, hair growth! Not only that, but RLT can also increase the growth rate in the anlagen phase while disallowing premature catagen phases, leading to a healthier head of hair.
Other mechanisms by which RLT may help hair health includes improving particular growth factors, modulation of inflammation, improved health and efficiency of mitochondrial functioning and/or positive effects on nitric oxide levels and blood flow to the area.
Recent research has demonstrated that external light (i.e., red light) regulates hair follicle stem cell (HFSC) activity by stimulating the eye and, thus, exerting a significant hair regenerative capacity via intrinsically photosensitive retinal ganglion cells (ipRGC)/suprachiasmatic nucleus (SCN)/sympathetic neural pathway.
The proliferation of HFSCs is a prerequisite for the initial anagen phase of hair follicles. Under numerous biological or pathological conditions, inadequate activation and/or inhibition of HFSCs lead to hair loss.
Recent research has indicated that RLT drives HFSC activation by inhibiting β-catenin degradation (β-catenin is a signaling molecule and essential for fate decisions of hair stem cells; β-catenin degradation = hair loss)
As a quick reminder, hair follicle atrophy caused by aging is a common type of hair loss. Ultimately, the activation of HFSCs is an effective means to alleviate aging-induced hair loss.
What does the research show?
“In this study, we found that PBMT drove the activation of hair follicle stem cells and alleviated hair follicle atrophy caused by aging.” (1)
“PBM provides a stimulus for hair density in 5 weeks… This study showed that the PBM is effective and promoted safe results with a reduced number of sessions for the androgenetic alopecia treatment.” (2)
“Collectively, our work suggests that PBMT promotes hair regeneration through synergetic activation of β-CATENIN in hair follicle stem cells.” (3)
In our study, the results showed statistically significant increase in total hair count from baseline to post-treatment at week 16… In conclusion, PBM of the scalp at 655nm (i.e., red light) improved hair counts in female pattern hair loss significantly. (4)
"The majority of studies covered in this review found an overall improvement in hair regrowth, thickness, and patient satisfaction following LLLT (low level laser therapy) therapy." (5)
"Our results suggest that LLLT treatment may be an effective option to treat pattern hair loss in both men and women.” (6)
"Subjects receiving LLLT at 655 nm achieved a 37% increase in hair counts as compared to sham treated control patients in this multi-center randomized controlled trial." (7)
"LLLT appears to be a safe, alternative treatment for patients with androgenic alopecia. Clinical trials have indicated efficacy for androgenic alopecia in both men and women." (8)
**While the current scientific research seems to indicate many positive benefits of RLT in relation to hair health and preventing hair loss, there is still an appreciable necessity for more extensive research to be conducted in this area, including double-blind RCT (randomized controlled trials), to provide a more comprehensive, robust overview that will further elucidate the optimal parameters and appropriate uses of RLT, which will ultimately lead the most safe and efficacious uses for individuals looking to prevent hair loss and improve overall hair health.
(1) Jin H, Zou Z, Chang H, Shen Q, Liu L, Xing D. Photobiomodulation therapy for hair regeneration: A synergetic activation of β-CATENIN in hair follicle stem cells by ROS and paracrine WNTs. Stem Cell Reports. 2021 Jun 8;16(6):1568-1583. doi: 10.1016/j.stemcr.2021.04.015. Epub 2021 May 20. PMID: 34019818; PMCID: PMC8190671.
(2) Scarpim, Ana Cláudia et al. “Photobiomodulation Effectiveness in Treating Androgenetic Alopecia.” Photobiomodulation, photomedicine, and laser surgery vol. 40,6 (2022): 387-394. doi:10.1089/photob.2022.0011
(3) Jin H, Zou Z, Chang H, Shen Q, Liu L, Xing D. Photobiomodulation therapy for hair regeneration: A synergetic activation of β-CATENIN in hair follicle stem cells by ROS and paracrine WNTs. Stem Cell Reports. 2021 Jun 8;16(6):1568-1583. doi: 10.1016/j.stemcr.2021.04.015. Epub 2021 May 20. PMID: 34019818; PMCID: PMC8190671.
(4) Amer, Mohamed et al. “Results of low-level laser therapy in the treatment of hair growth: An Egyptian experience.” Dermatologic therapy vol. 34,3 (2021): e14940. doi:10.1111/dth.14940
(5) Afifi, L., Maranda, E. L., Zarei, M., Delcanto, G. M., Falto-Aizpurua, L., Kluijfhout, W. P., & Jimenez, J. J. (2016). Low-level laser therapy as a treatment for androgenetic alopecia. Lasers in Surgery and Medicine, 49(1), 27–39. doi:10.1002/lsm.22512
(6) J Jimenez, Joaquin & Wikramanayake, Tongyu & Bergfeld, Wilma & Hordinsky, Maria & G Hickman, Janet & Hamblin, Michael & A Schachner, Lawrence. (2014). Efficacy and Safety of a Low-level Laser Device in the Treatment of Male and Female Pattern Hair Loss: A Multicenter, Randomized, Sham Device-controlled, Double-blind Study. American journal of clinical dermatology. 15. 10.1007/s40257-013-0060-6.
(7) Lanzafame, Raymond & Blanche, Raymond & P. Chiacchierini, Richard & R. Kazmirek, Eric & A. Sklar, Jeffrey. (2014). The Growth of Human Scalp Hair in Females Using Visible Red Light Laser and LED Sources. Lasers in Surgery and Medicine. 46. 10.1002/lsm.22277.
(8) Darwin, E., Heyes, A., Hirt, P. A., Wikramanayake, T. C., & Jimenez, J. J. (2017). Low-level laser therapy for the treatment of androgenic alopecia: a review. Lasers in Medical Science, 33(2), 425–434. doi:10.1007/s10103-017-2385-5