Generality
The use of green tea against hair loss appears to be a potentially effective practice that can offer an alternative remedy to combat this disorder. In particular - as confirmed by several studies conducted on the subject - it can be useful when hair loss is caused by androgenetic alopecia.
Action mechanism
Green tea can be useful to counteract hair loss due to its richness in flavonoids, vitamins, trace elements, catechins and other antioxidant substances, both when applied to the scalp in the form of hydro-alcoholic extract, and when taken directly orally as an aqueous extract (infusion).
Green tea can prove to be a valid aid against hair loss also and above all for its ability to inhibit the activity of the enzyme 5-alpha-reductase type I, an action ascribed in particular to the polyphenols epigallocatechin-3-gallate and epicatechin- 3-gallate .
Type I 5-alpha-reductase is especially expressed in hair follicles and is the enzyme responsible for the conversion of testosterone into dihydrotestosterone (DHT). It is the latter compound that causes the miniaturization of hair follicles in androgenetic alopecia, which inevitably follows hair loss.
Through the action of the epigallocatechin-3-gallate and epicatechin-3-gallate - demonstrated in vitro and on animal models (see bibliography) - green tea could help to normalize sebaceous secretion, counteract hair loss and promote hair regrowth.
Topical applications of these catechins could be adopted in the future as natural alternatives to synthetic drugs (such as dutasteride and finasteride) still used against androgenetic alopecia.
In this sense, green tea is added to the long list of natural substances and extracts that have shown inhibitory activity against the enzyme 5-alpha-reductase, including the Serenoa repens, the African pigeo, the nettle root, the capsicin contained in chilli and gamma-linolenic acid.
The image shows the comparison between the structure of finasteride - the drug currently most used in the treatment of androgenetic alopecia (main cause of hair loss) - and the structure of the active substances of green tea that have shown the same inhibitory effect in the against the enzyme 5-alpha reductase type I.
Other properties
In addition to the potential ability to counteract hair loss, the green tea infusion - again thanks to its high antioxidant content - can perform other beneficial functions for the hair.
In fact, if applied in the form of a pack or if used to make rinses, it can help to strengthen the hair, giving them a healthier and brighter appearance.
Bibliography
Hiipakka, RA, Zhang, HZ, Dai, W., Dai, Q., Liao, S., 2002.
Structure – activity relationships for inhibition of human 5alpha-reductases by polyphenols. Biochem. Pharmacol. 63, 1165–1176.
Phytomedicine. 2007 Aug; 14 (7-8): 551-5. Epub 2006 Nov 7. In vitro human hair growth enhancement by green tea epigallocatechin-3-gallate (EGCG). Kwon OS, Han JH, Yoo HG, Chung JH, Cho KH, Eun HC, Kim KH.
Effects of topical application of EGCG on testosterone-induced hair loss in a mouse model.
Kim YY, Up No S, Kim MH, Kim HS, Kang H, Kim HO, Park YM.
Exp Dermatol. 2011 Jul 27. doi: 10.1111 / j.1600-0625.2011.01353.x.
