I used to drink a lot of green tea, but I don’t do that anymore.
It’s not that I don’t like green tea because I really do.
Green tea has had a long history of fairly safe use.
But it does have some hidden side effects that are pretty powerful.
It makes you wonder is green tea bad?
And that is the reason I don’t drink it much anymore.
It’s possible that the same problems in green tea may apply to black tea as well.
But we don’t know that yet, but we do know about the effects of green tea.
And these side effects are also a very important reason not to take popular extracts of green tea.
You can get these extracts in capsules or as a powder.
And they’re typically labeled as polyphenols or green tea catechins.
These extracts are especially concentrated.
And they’re more likely to cause the bad effects that I’m going to show you in this study.
So here’s the bad part.
This green tea extract had terrible effects on male rats.
It was found that a 5% dose to male rats for 2-8 weeks induced goiters and decreased weights of the body, testis and prostate gland.
There was one sort of good effect here, too.
The positive effect was that green tea extract was found to stop the conversion of testosterone into estrogen.
But I kind of doubt this result.
And that’s even though these researchers said that in the male mice, testosterone levels rose.
I doubt it because luteinizing hormone rose.
And that usually happens when testosterone falls in these situations:
higher luteinizing hormone and testosterone levels were induced by this treatment.
Testosterone and green tea don’t get along at all.
But the bad news also continued.
Because as I’ve explained before, the green tea extract was very anti-thyroid.
We saw above that green tea extract causes goiter.
Goiter is a symptom of blocked thyroid function.
Indeed, the levels of thyroid hormone fell dramatically!
And so these rats became low in thyroid as a result of taking the green tea extract.
Green tea caused:
decreasing tri-iodothyronine (T(3)) and thyroxine (T(4)) levels.
These rats were getting the equivalent of many many cups of green tea per day.
But if you use matcha tea, you may be getting high levels as well.
You won’t get as much as the rats, but it’s still a lot.
I don’t think an occasional cup of green tea will hurt you, and it may not even be bad drinking it every day.
But it certainly is bad to use those extracts.
These are known variously as polyphenone-60 (P-60), green tea extract catechins, or green tea polyphenols.
This study confirms what has become known about green tea extracts for some time.
And it clarifies that green tea LOWERS testosterone:
After treatment it was found that, the weight of the testis was markedly reduced instead of normal weight gain of all the animals.
The sperm count and motility were reduced for the treated groups as compared with control animal group.
Testosterone level was reduced in the treated groups.
So, why do the two studies conflict?
I think that the first researchers did not measure testosterone very well.
All of the other laboratory markers they measured all would point to lower testosterone levels.
I think that they made a mistake.
Many other studies confirm that green tea lowers testosterone.
Just like the study we just looked at.
And especially green tea extract or something like matcha is probably a bad idea.
I would avoid them.
Effect of green tea (Camellia Sinensis l.) leaf extract on reproductive system of adult male albino rats