I would love to see the source. If green tea extract actually did that all the old Japanese granny's would be jacked... I saw a study stating green tea extract raised testosterone and I have also seen other studies saying that it lowered test.
Sure thing: and by the way thats a HUMAN study not rats like most things out there. And most japanease are fit they have one of the lowest obesity rates in the world. HGH and IGF-1 won't leave you JACKED but rather skinny. Unless you are training for muscles... plus you have to take into consideration genetic limitations.
HGH study below:
Di Pierro, F., Menghi A.B., Barreca, A., Lucarelli, M, and Calandrelli, A. 2009. Greenselect Phytosome as an adjunct to a low-calorie diet for treatment of obesity: a clinical trial. Alternative Medicine Review 14(2):154-160.
Testosterone is controversial and most are either rat or in vitro studies. I read a british study (in vitro) where EGCG was found to be a strong inhibitor of the UGT2B17 enzyme, responsible for adding a sugar molecule to testosterone rendering it inactive.
''According to a 2002 study done at the State University of New Jersey, the concentration of phenols such as epigallocatechin-3-gallate (EGCG), epigallocatechin (EGC) and epicatechin (EC) reaches maximum levels 1-2 hours after consuming a green-tea extract. [Cancer Epidemiol Biomarkers Prev. 2002 Oct; 11(10 Pt 1): 1025-32.] The levels are so high that they must have an effect on enzymes.
The Brits decided to test it out. They bought dragon beard white tea (WT), Yunnan white tea leaf (WTL), sencha Japanese green tea bags (GT) and white tea powder (WTP).
The last mentioned product was from Burgundy Botanical Extracts, and was an extract intended for cosmetic use. [burgundy-extracts.com] The researchers bought the other products in an ordinary shop. They put 1.6 g tea in 80 ml boiling water, filtered out the leaves and used the cooled down tea for their trials.''