Androgenetic alopecia (AGA), also known as congenital hair loss, is characterized by the progressive thinning and subsequent loss of hair on the head. AGA usually occurs around the age of 20; by the age of 50, almost 50% of all men are affected. This widespread dermatological phenomenon affects both men and women and usually has a negative impact on the quality of life of those affected.
Green tea is not only a popular drink worldwide, but is also known for its health-promoting properties. Its anti-oxidative and anti-cancer properties are currently attributed by researchers to its component epigallocatechin-3-gallate (EGCG). Current scientific findings suggest that EGCG may also be effective in the treatment or prevention of hereditary hair loss (so-called androgenic alopecia, also known as “AGA”). This is attributed to the selective inhibition of 5-alpha-reductase by EGCG.
In the study summarized below, the effect of EGCG on hair growth was investigated in vitro; in addition, the effect on the dermal papilla cells was investigated in vitro and in vivo. Hair growth takes place in a repetitive cycle of anagen, catagen and telogen phases. Dermal papilla cells, a group of specialized fibroblasts within the hair follicle bulb, assume an essential function in the control of hair growth. They perform this function not only within the normal hair growth cycle, but also, for example, in the pathogenesis of congenital hair loss. The possibility of influencing the functions of dermal papilla cells is therefore of great importance in the treatment and prevention of hair loss symptoms.
Both the so-called hair follicle organ culture model (HOKM) and cultured normal dermal papilla cells were used as an in vitro model in the underlying study. Scalp tissue samples taken after topical application of EGCG were used as an in vivo model. It was shown that EGCG promotes hair growth in vitro by upregulating the phosphorylated proteins Erk and Akt and by increasing the ratio of Bcl-2 and Bax.
In addition, statistical analysis methods (such as the Wilcox rank sum test) and tests using the Western blot methodwere carried out as part of the study.
EGCG promoted hair growth in hair follicles both in the hair organ culture model (HOKM) and in vivo and also promoted the proliferation of cultured dermal papilla cells. This growth stimulation of dermal papilla cells was also observed in vivo in the study. The authors of the study therefore attribute the hair growth-promoting property of EGCG to a combination of proliferating and anti-apoptopic effects and an anagen phase prolonged by EGCG.
Conclusion
The underlying study showed that the active component of green tea, epigallocatechin-3-gallate (EGCG), significantly promotes hair growth.
Underlying study:
Kwon, O. S. et al: Human hair growth enhancement in vitro by green tea epigallocatechin-3-gallate (EGCG); in: Phytomedicine 2007 August; 14 (7-8):551-5.