A study1 published in the June 2011 issue of the Journal of Dermatological Science may shed some light on the mechanisms by which minoxidil promotes hair regrowth.
Minoxidil, the FDA-approved active ingredient in Avacor Physicians Formulation®, has been clinically proven to regrow hair in patients with androgenetic alopecia (AGA). Although minoxidil is a vasodilator and is known to increase circulation and blood flow to the scalp, it is not completely clear how it achieves hair regrowth in AGA patients at the molecular level.
This exciting research shows that minoxidil activates the β-catenin pathway in vitro in cultured human dermal papilla cells, a population of cells in the hair follicle involved in the induction and maintenance of hair growth.
Previous research on β-catenin from Harvard Medical School has shown that β-catenin activity in the dermal papilla regulates the regeneration of hair2 and scientists at the University of Michigan found that simply activating β-catenin in skin cells is sufficient to trigger the active growth phase of the hair cycle in mice.3
While this finding still needs to be confirmed by other research groups, the authors’ suggestion that “minoxidil extends the anagen phase by activating β-catenin activity” offers an exciting hypothesis on the mechanism of action of minoxidil.
This hypothesis is especially interesting in light of other research showing that dihydrotestosterone (DHT), the hormone that causes AGA, inhibits β-catenin activity in hair follicle cells (see our previous post on "Mouse-Pattern Baldness").
Taken together, these two conclusions raise the possibility that 5-alpha reductase inhibitors (which block DHT production) could work in concert with minoxidil to further increase β-catenin activity and hair regeneration. Future research into any such potential additive or synergistic effects would be of great interest to the hair regrowth community.
1. Kwack MH, Kang BM, Kim MK, Kim JC, Sung YK. Minoxidil activates beta-catenin pathway in human dermal papilla cells: A possible explanation for its anagen prolongation effect. J Dermatol Sci. 2011 Jun;62(3):154-9. Link to Pubmed
2. Enshell-Seijffers D, Lindon C, Kashiwagi M, Morgan BA. Beta-catenin activity in the dermal papilla regulates morphogenesis and regeneration of hair. Dev Cell. 2010 Apr 20;18(4):633-42. Link to Pubmed
3. Van Mater D, Kolligs FT, Dlugosz AA, Fearon ER. Transient activation of beta-catenin signaling in cutaneous keratinocytes is sufficient to trigger the active growth phase of the hair cycle in mice. Genes Dev. 2003 May 15;17(10):1219-24. Link to Pubmed