Androgenetic Alopecia and Limited Medicated Treatment Options
Androgenetic alopecia (AGA) is the most common cause of hair loss in men and women. Over half of all men by the age of 50, and the same proportion of women by the age of 80, will experience some degree of permanent hair loss due to AGA.
Much is known about how AGA causes hair loss. Normally, hair follicles repeatedly cycle through growth (anagen) and rest (telogen) stages, but in individuals with AGA, hair follicles in genetically predetermined areas of the scalp gradually spend more and more time in the resting stage. Additionally, each growth stage produces a smaller and smaller hair shaft caused by a progressive miniaturization of the hair follicle. Eventually, the follicle stops producing hair ((Alonso L and Fuchs E. “The Hair Cycle,” February 1, 2006 J Cell Sci 119, 391-393.)).
Hair loss caused by AGA can be stopped by existing medications, but to date, only two FDA-approved drugs are available for treatment of AGA: finasteride (Proscar ®) and topical minoxidil (Rogaine®). Unfortunately, up to 3 out of 10 individuals will not respond to one or more of these drugs ((Fischer TW, Hipler UC, Elsner P. “Effect of Caffeine and Testosterone on the Proliferation of Human Hair Follicles in vitro.” Int J Dermatol 2007; 46: 27-35.)). Because of this, researchers have searched for alternate treatments, especially for women since finasteride is not approved for use in female patients.
Caffeine: A Possible Alternative Treatment?
One possible alternative substance is caffeine. This is because as a phosphodiesterase-inhibitor, caffeine increases cellular metabolic activity ((Green H. “Cyclic AMP in relation to proliferation of the epidermal cell: a new view.” Cell 1978;15: 801-11.)). Researchers theorize that this could counteract the miniaturization of the hair follicle ((Fischer TW, Hipler UC, Elsner P. “Effect of Caffeine and Testosterone on the Proliferation of Human Hair Follicles in vitro.” Int J Dermatol 2007; 46: 27-35.)).
Indeed, using cell-cultured (i.e., in vitro or “test tube”) male human hair follicles, researchers have demonstrated that caffeine reverses testosterone’s inhibitory effect on keratinocyte proliferation, which could lead to increased hair shaft cell production. Researchers have also demonstrated that caffeine normalizes testosterone’s inhibition of hair shaft elongation ((Fischer TW, Hipler UC, Elsner P. “Effect of Caffeine and Testosterone on the Proliferation of Human Hair Follicles in vitro.” Int J Dermatol 2007; 46: 27-35.)).
Evidence that Caffeine can Stimulate Hair Follicle Growth in Cell-Cultures and Protect those Hair Follicles from the Effects of AGA
A 2014 paper in the British Journal of Dermatology ((Fischer TW, Herczeg-Lisztes E, Funk W, Zillikens D, Bíró T, Paus R. “Differential effects of caffeine on hair shaft elongation, matrix and outer root sheath keratinocyte proliferation, and TGF-β2-/IGF-1-mediated regulation of hair cycle in male and female human hair follicles in vitro.” Br J Dermatol. 2014 May 16)). reported that caffeine stimulated hair growth in cell-cultured follicles in three ways:
- It enhanced hair shaft elongation in both male and female cell-cultured follicles.
- It increased the number of hair matrix keratinocytes, i.e., cells that create the hair shaft and its surrounding protective structure (the inner and outer root sheath), in both male and female cell-cultured hair follicles.
- It increased the stimulation of a hair growth factor called IGF-1 in both male and female cell-cultured hair follicles.
The paper also reported that caffeine may protect cell-cultured hair follicles against the effects of AGA in two ways:
- It reversed testosterone’s suppressive effects on the anagen (growth) stage of both male and female cell-cultured hair follicles, one of the primary mechanisms of hair loss in AGA.
- It protected both male and female cell-cultured hair follicle against apoptosis, a process that leads to the end of the anagen (growth) stage of hair follicles. This is significant because premature exit from anagen is another mechanism of hair loss in AGA.
In sum, this 2014 research not only replicates a past finding that caffeine counteracts some of the hair growth suppression mechanisms of AGA but also, for the first time, shows that caffeine stimulates hair growth in both male and female cell-cultured hair follicles. Its beneficial effects have yet to be shown in humans.Posted by