Theaflavins, an active constituent of Black Tea, consumed in sufficient doses, have been shown in this prior study, to reduce DHT in animal model by 72%, which is the equivalent reduction obtained in animal models by 5 mg of finasteride,(Proscar). 

      When this study initially appeared several years ago, we gave away many samples of Theaflavin Extract, under the condition that feedback was provided to us regarding DHT levels, to determine if these results could be replicated in humans. The results were encouraging, with most reporting reductions in blood levels of DHT, and a generally positive effect on hair growth, with an average of 3-4 month usage time. It was also found that most respondents, who were over 170-180 lbs, needed 2 capsules as opposed to one, to obtain pronounced reductions in DHT. 

      Finasteride,(Proscar, Propecia) reduces DHT by inhibiting 5 Alpha Reductase, the enzyme which converts Testosterone into DHT, which is causatively implicated in Prostate Enlargement, Androgenetic Alopecia, (male and female pattern hair loss), hirsutism, and to a large degree, Acne. 

      This study we obtained demonstrated that Theaflavin from Black Tea, shares the same exact mechanism, and additionally, down regulates androgen receptor activity, which Finasteride doesn�t do.

Theaflavin-3,3′-digallate and penta- O -galloyl-β- d -glucose inhibit microsomal 5α-reductase activity and the expression of androgen receptor in LNCaP prostate cancer cells 
Hung-Hsiao Lee,Chi-Tang Ho
Carcinogenesis  (7): 1109-1118.

Androgens play a critical role in regulating the growth, differentiation and survival of epithelial cells in many androgen-responsive organs, such as prostate and skin. The enzyme steroid 5α-reductase (EC catalyzes the conversion of testosterone (T) to a more active androgen, dihydrotestosterone (DHT). DHT then binds to androgen receptors (AR) and functions in the nucleus to regulate specific gene expression. Androgens via their cognate receptor may be involved in the development and progression of benign prostate hyperplasia, prostate cancer, hirsutism, male pattern alopecia and acne. The aim of this study was to determine whether theaflavin-3,3′-digallate (TF3) and penta- O -galloyl-β- d -glucose (5GG) have inhibitory effects on androgen production and action. We found that TF3 and 5GG inhibit microsomal 5α-reductase activity. Furthermore, TF3 and 5GG significantly reduced androgen-responsive LNCaP prostate cancer cell growth, suppressed expression of the AR and lowered androgen-induced prostate-specific antigen secretion and fatty acid synthase protein level. In conclusion, our result suggests that TF3 and 5GG might be useful chemoprevention agents for prostate cancer through suppressing the function of androgen and its receptor. 

The results of this study, which was conducted in rats were further supported in this follow-up investigation on humans:

Black Tea Polyphenols Theaflavins Inhibit the Growth of LNCaP Prostate Cancer Cells through Suppressing Androgen Receptor and 5α-Reductase Activity

Many rightfully ask if using Theaflavin (Black Tea Extract) would have the same negative side effects on sexual and cognitive function that are associated with Propecia (finasteride) and Avodart (dutasteride). The answer is not only no, but quite the opposite.

Theaflavins are actually documented to enhance libido and sexual behavior due likely,(in addition to DHT reduction)to an increase in Testosterone and reduction in Estrogen associated with its usage. 

Our recommendation to those seeking to use Theaflavin Extract as a side effect free substitute for Propecia, is to use a minimum of 1 capsule a day if you are under 170 lbs and two capsules a day if you are over 170 lbs.