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Venom 03-31-2009 05:13 PM

Green Tea inhibits Testosterone Production, and increase aromatase activity
1 Attachment(s)
Enough for me to stop using this! Attached one article, here are few abstracts.


Green tea polyphenols inhibit testosterone production in rat Leydig cells.

Figueiroa MS, César Vieira JS, Leite DS, Filho RC, Ferreira F, Gouveia PS, Udrisar DP,Wanderley MI.

1Department of Physiology and Pharmacology, Federal University of Pernambuco, 50607-901 Recife, PE, Brazil.

This study investigated the acute effects of green tea extract (GTE) and its polyphenol constituents, (-)-epigallocatechin-3-gallate (EGCG) and (-)-epicatechin (EC), on basal and stimulated testosterone production by rat Leydig cells in vitro. Leydig cells purified in a Percoll gradient were incubated for 3 h with GTE, EGCG or EC and the testosterone precursor androstenedione, in the presence or absence of either protein kinase A (PKA) or protein kinase C (PKC) activators. The reversibility of the effect was studied by pretreating cells for 15 min with GTE or EGCG, allowing them to recover for 1 h and challenging them for 2 h with human chorionic gonadotropin (hCG), luteinizing hormone releasing hormone (LHRH), 22(R)-hydroxycholesterol or androstenedione. GTE and EGCG, but not EC, inhibited both basal and kinase-stimulated testosterone production. Under the pretreatment conditions, the inhibitory effect of the higher concentration of GTE/EGCG on hCG/LHRH-stimulated or 22(R)-hydroxycholesterol-induced testosterone production was maintained, whereas androstenedione-supported testosterone production returned to control levels. At the lower concentration of GTE/EGCG, the inhibitory effect of these polyphenols on 22(R)-hydroxycholesterol-supported testosterone production was reversed. The inhibitory effects of GTE may be explained by the action of its principal component, EGCG, and the presence of a gallate group in its structure seems important for its high efficacy in inhibiting testosterone production. The mechanisms underlying the effects of GTE and EGCG involve the inhibition of the PKA/PKC signalling pathways, as well as the inhibition of P450 side-chain cleavage enzyme and 17beta-hydroxysteroid dehydrogenase function.Asian Journal of Andrology advance online publication. 30 March 2009; doi: 10.1038/aja.2009.2.

Chronic green tea consumption decreases body mass, induces aromatase expression, and changes proliferation and apoptosis in adult male rat adipose tissue.

Monteiro R, Assunção M, Andrade JP, Neves D, Calhau C, Azevedo I.

Department of Biochemistry, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal.

Green tea (GT) and its components have been shown to possess antiobesity properties and the corresponding mechanisms of action are being investigated, given the epidemic proportions of obesity incidence. In the current work, we used 12-mo-old male Wistar rats to test the effect of 6 mo of treatment with GT as the sole drinking beverage (52.8 +/- 6.4 mL/d) on adipose tissue (AT). AT aromatase expression was determined by Western blotting, plasma concentrations of 17beta-estradiol and testosterone were determined by RIA, and adipocyte size determined by measuring diameter in tissue sections. Proliferation and apoptosis were also assessed by Ki67 immunostaining and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling, respectively. Evaluations were made in subcutaneous (sc) AT and visceral (v) AT. Body weight increased over time in both groups (P < 0.001), but the increase was more pronounced in controls (P < 0.001) and food and fluid intake did not influence that effect. At the end of the experiment, aromatase expression increased in the AT (318.5 +/- 60.6% of control in scAT, P < 0.05, and 285.5 +/- 82.9% of control in vAT, P < 0.01). AT of GT-treated rats had a higher percentage of proliferating cells (204.1 +/- 19.5% of control in scAT, P < 0.01, and 246.6 +/- 50.2% of control in vAT, P < 0.01) and smaller adipocytes (78.3 +/- 1.7% of control in scAT, P < 0.001, and 87.9 +/- 3.2% of control in vAT, P < 0.05). GT also increased the number of apoptotic cells in vAT (320.4 +/- 21.9% of control; P < 0.001). These results suggest new mechanisms for GT on body weight and highlight its potential benefit to prevent or treat obesity and the metabolic syndrome.

Well according to this, aromatase increased 60% in the adipose tissue with chronic green tea use. This number is huge. They also say they measured estradiol and testosterone.

"Plasma 17β-estradiol and testosterone concentrations. The plasma concentration of 17β-estradiol was undetectable in control rats, whereas that of GT-treated rats was 39.2 ± 10.4 pmol/L (P < 0.01). The plasma testosterone concentration was lower in GT-treated rats (790 ± 177 pmol/L) than in controls (2720 ± 769 pmol/L; P < 0.01)."

Commander 03-31-2009 05:24 PM

Any human studies?

I drink 4 cups of green tea per day, so am definitely interested in this.

fightbackhxc21 03-31-2009 09:29 PM

awww bummer, i like the healthy properties GT is known for :/

Ordo Ab Chao 03-31-2009 10:48 PM

do you think these results apply to other antioxidants/polyphenols or just the ones in green tea?

EDIT: also, unless I'm mistaken, these studies address acute GT extract consumption. What about chronic use? Do you think it would be less or more detrimental to testosterone?

Venom 04-01-2009 12:16 AM

No, these were chronic chronic. Not sure about other anti-oxidants...good question.

RawIron 04-01-2009 01:19 PM

bahhh. you have no idea how much green tea i drink!......"drank"

Any idea about coffee? A fat girl at work told me that she read coffee makes you gain fat. She doesn't drink coffee.... however shes fat anyway. So i just don't listen to her. Besides, I drink coffee constantly. When I started my cut I was over 220 and this morning I weighed in at 205. So... yea.

Venom 04-01-2009 02:55 PM

It's not coffee, it's caffeine in coffee that's debated. It's a difficult has fat mobilizing properties; but chronically, could cause some issues on fat gain. I debate it in my mind constantly lol. For a variety of reasons I have none, or minimal (<50 mg) of it daily.

As for effecting test like green tea, I have not seen anything like that.

Commander 04-01-2009 02:59 PM

Do rat studies correlate well with what we can expect to see in humans?
How much would one need to drink per day to be comparable to the results they got in these studies?

Venom 04-01-2009 03:06 PM

Yes, they generally do. Though we always like to replicate them in humans. Usually the magnitudes are greater in rats.

I don't know exactly how much green tea this relates to humans, or if there is a threshold.

Commander 04-01-2009 03:12 PM

Found this over at

Possible side effects and precautions
A concern that is commonly brought up about green tea is the idea that it decreases levels of androgens such as testosterone and DHT. One study reported that after administered to rats, EGCG "significantly reduced food intake; body weight; blood levels of testosterone, estradiol, leptin, insulin, insulin-like growth factor I, LH, glucose, cholesterol, and triglyceride" [22]. However, a different study with green tea catechins in rats found decreased body weight but increased thyroid stimulating hormone (TSH), LH, and testosterone levels [85]. A final study in mice with green tea indicated drastic increases in both testosterone and DHT from green tea treatment, but levels of both were synergistically inhibited when it was adminstered along with soy phytochemicals [86]. In vitro, EGCG inhibits type I 5AR [2, 87], which is partially responsible for the conversion of testosterone to DHT (for this reason, it has been proposed in the topical treatment of acne and hair loss [2]), while in rats, green tea is an aromatase inhibitor, which (in theory) would be responsible for an increase in tesotsterone levels [85].

So, how does one make sense of this mess of contadictory data? It should first be noted that 5AR inhibition has only been shown in vitro [87], while it has not been observed in live animals – in fact, drastic increases in DHT have been found - and it seems that other constituents of green tea counteract the 5AR inhibition [88]. The conclusions of the first study, which found drastic decreases in body weight, testosterone, and other hormones, are very misleading. A drastic reduction in levels of all of the substances mentioned can unfortunately be expected from weight loss in any situation (which is one of the reasons losing weight without losing muscle mass is so difficult). Indeed, when the authors of the same study restricted the food intake of the rats to cause a similar weight loss to that induced by EGCG, similar effects were seen, implying that the changes were not due to EGCG but due to drastic body weight loss [22]. The effect green tea has on levels of androgens and other hormones is complex and depends on various factors, but no detrimental effects have as of yet been seen in human populations.

It tries to make sense of some of the contradictory data, thoughts?

Seems that some of the results may be to reduced food intake/reduction in bodyweight.

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