Green tea has no effect on testosterone
According to some in vitro and animal studies, green tea raises testosterone levels. Green tea flavonoids like EGCG would inhibit an enzyme that neutralizes testosterone. But there are also animal studies in which green tea lowers testosterone levels. [Indian J Exp Biol. 2011 Sep;49(9):689-97.] So what exactly is the effect of green tea? A human study published by Spanish researchers in Drug Testing & Analysis may provide an answer.
The researchers got 29 male test subjects to drink 5 cups of green tea every day for 6 consecutive days. The men received 520 milligrams of EGCG every day. On day 7 the men drank 9 cups of green tea. It contained 936 milligrams of EGCG.
Three days before the men started drinking green tea, the researchers started collecting the men's urine and determining the concentration of testosterone in it.
The researchers divided the men into 2 groups: in a group with a relatively low T/E ratio in their urine and a group wit a relatively high T/E ratio. [T: testosterone; E: epitestosterone] People with a relatively low T/E ratio have relatively little testosterone in their urine, while people with a relatively high T/E ratio have a lot.
The test subjects with a relatively low T/E ratio had somewhat more EGCG in their blood than the other subjects, the first figure below shows.
During the experiment, the testosterone concentration in the urine of the test subjects did not change, as shown above.
The Spaniards also looked at the concentration of epitestosterone, androsterone, etiocholanolone, 5-alpha-androstan-3-alpha,17-beta-diol and 5-beta-androstan-3-alpha,17-beta-diol in the urine. Green tea had no effect on the concentration of these substances either.
The research was paid for by the international doping authority WADA. WADA wanted to know if green tea confuses the traditional doping tests that detects the use of testosterone.
Apparantly it doesn't.
Drug Test Anal. 2018 Sep;10(9):1438-47.
Tea for temporary testosterone boost 24.04.2012
Tea supplement boosts testosterone levels in animal study 30.10.2010