Green tea is one of the most powerful health-promoting drinks in existence. It’s chock full of potent antioxidants to go beast mode against those pesky free radicals that threaten your livelihood on a daily basis.
Free radicals being created within your body is completely normal and, believe it or not, is actually necessary to keep you alive. But without a consistent, ample supply of antioxidants to keep the level of free radicals within your body under control, they will gradually accumulate – and will eventually wreak havoc.
Cancer, heart disease, premature aging, stroke, ulcers and osteoporosis (among other undesirable conditions) are all believed to be caused – at least in part – by the proliferation of free radicals within the body.
So the fact that green tea is a natural, zero-calorie beverage that contains a relatively high amount of antioxidants makes it a favorite among those of us who are conscious about our health and understand that an ounce of prevention is indeed worth a pound of cure.
And, for the win, green tea also contains caffeine.
Due to the high amount of relatively powerful antioxidants (the catechins in green tea, for example, are about 2x more potent as antioxidants than vitamin C), green tea has been linked to various pragmatic health benefits, including: reduced cancer risk, reduced risk of type 2 diabetes, decreased risk of cardiovascular disease, and can even induce weight loss by increasing energy expenditure and fat oxidation.
These incredible benefits afforded us by simply sipping on some tea on a regular basis are nothing short of amazing.
But underneath all that health-promoting utopia may be lurking a sinister dark side to green tea that’s secretly shrinking men’s testicles, lowering testosterone levels, and killing muscle gains.
Okay. Let’s take a deep breath and not jump to hasty conclusions here. Let’s objectively examine what we know and take it from there.
Fair enough? Okay.
First up we have this in-vitro study in which researchers incubated isolated rat leydig cells with green tea catechins (GTC) for 3 hours, while simultaneously checking the testosterone content and various enzyme reactions in the cells when under the the influence of the green tea antioxidants.
I’m sure you already know what leydig cells are. But, just in case, these are the cells within the gonads responsible for the production of testosterone.
What this study found was that each of the catechins applied to the cells in this study (EGCG and EGCG/EC) produced an inhibitory effect on basal and stimulated testosterone production. Not good.
Here are a couple of graphs that show the impact each of these catechins had on testosterone production (note: you can click on either image to view in a new window and zoom in):
At first glance, this appears to be a fairly damning link between the consumption of green tea and the reduction of testosterone production.
However, a problem with drawing such a conclusion from this particular study is that it was done in-vitro, or isolated-cell-style, which allowed for the exposing of these animal cells to amounts of green tea catechins far greater than someone could ever drink. We also have the fact that the study was performed on the cells of male rodents and not male humans.
On top of this, another recent study, also done in-vitro, found the opposite effect: That green tea actually boosted testosterone production. 1
Okay. So we’re forced to admit at this point that the results of these two studies are, at best, inconclusive. But these are in-vitro studies that are isolating cells of the body apart from the complete symbiotic system in which they normally function.
This study, on the other hand, involved live, male rodents being injected with the primary catechin found in green tea (EGCG). The dosage applied in this study would be roughly equivalent to a 200lb male human receiving 7.2 grams of EGCG per day.
This level of EGCG is still far more than any person would drink via green tea in a given day, but it’s obviously being administered in higher concentration for a more dramatic biological effect that will be easier to identify and measure by the researchers.
The results of this particular study are rather alarming.
Only 7 days into the study the testicle mass of the rats being injected with EGCG had decreased by a substantial 10-20%. As if that wasn’t bad enough, testosterone levels also dropped by a whopping 50-70%!
And perhaps the most comprehensive study we have to date analyzing the link between green tea consumption and testosterone production is one that was conducted with dosage levels much closer to what human green tea drinkers might actually consume on a daily basis, with the dosages administered orally…
In this study, a group of Indian researchers gave the subsets of male rodent subjects varying doses of green tea extracts orally, as follows:
- The “mild” group received a dose that was the human equivalent of 5 cups of green tea per day
- The “moderate” group received a dose equivalent to 10 cups per day
- The “high” group received an equivalent of 20 cups per day
- The control group received no green tea extract
The results of this study were glaringly consistent with the previous study referenced in which ECGC was injected into male rodents.
Testicular atrophy and a decrease in testosterone production were each experienced in amounts proportionate to the oral green tea extract dosage received.
The “mild” group experienced a 25% reduction in testosterone production, while the “moderate” and “high” groups had their testosterone levels reduced by 60% and 78%, respectively. The control group’s testosterone was virtually unaffected.
Unsurprisingly, the body weights measured at the end of this study for the various groups was inversely proportional to the dosages received. In other words, the more green tea extract consumed by the rodents, the less fat mass they had on their bodies at the end of the study, confirming the fat burning benefit already known to be associated with green tea consumption.
It would be easy to write these studies off, which appear to indicate a negative correlation between green tea consumption and testosterone production, as being performed on rodents and thus not representative of how green tea impacts humans. However, it’s worth noting that male rodents do share a similar endocrine system with human males.
So what should we take away from all this?
As with most other things fitness and nutrition related, I believe the answer is that it depends on your goals.
What these studies, and others, appear to point to is that if your primary goals pertain to weight loss, body fat control, disease prevention, and extending your life, consuming green tea on a regular basis is likely going to positively contribute to such goals.
On the other hand, because testosterone is a hormone whose muscle gaining prowess is undeniable – and it appears (at least for now) that green tea likely inhibits the production of testosterone in the body – those who desire to maximize muscle growth would do well to enjoy green tea in moderation (or abstain from drinking green tea altogether) while working toward building a more muscle-clad physique.
Finally, I want to mention that optimizing your testosterone levels naturally obviously requires more than just avoiding drinking green tea. There are a number of factors that play into maximizing this powerful fat burning and muscle building hormone.
If it’s important to you to have the highest natural levels of testosterone (i.e. without resorting to the use of dangerous synthetic steroids), you’ll want to click here to educate yourself on what it takes to turn this desire into a reality.
1 Jenkinson, C., et al. (2012). Dietary green and white teas suppress UDP-glucuronsyltransferase UGT2B17 mediated testosterone glucuronidation. Steroids. 77(6);691-695.