Testosterone and Vitamin E
Vitamin E is pro-testosterone, right? That is definitely a statement that
is quite commonly stated in health circles and I have read it many times.
However, is it really true?
As is so often the case, the exact opposite may very likely be true according to the
research. Researchers found that senior men with an average age of 60 without Vitamin E supplementation had testosterone of 573.
When they gave them supplemental alpha tocopherol, the testosterone dropped to 539 ng/dl.  This is about a 6% reduction in
testosterone. The dosage was fairly low, 50 mg/day, compared to the
normal dosage in supplementation, but researchers have long noted Vitamin E's
testosterone lowering powers.
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Although an animal study on rams found no statistically
significant change with administration of alpha tocopherol, 
within just a few years researchers reverified Vitamin E's anti-testosterone
powers.  In fact, that same study even identified exactly how Vitamin E
supplementation lowers testosterone and concluded: "Therefore, growth modulation
by the antioxidant moiety of vitamin E in androgen-sensitive prostate carcinoma
cells is due, at least in part, to its potent antiandrogenic activity."
Vitamin E's anti-testosterone powers are so strong that the authors actually
recommend its consideration for further study to prevent prostate cancer. Most
guys are completely unaware that their testosterone could be affected by a
vitamin such as this, especially negatively.
For those who have prostate cancer,
perhaps this is something to consider with your doctor. (I mention alternative ways to Prevent
Prostate Cancer and General Cancer Prevention.)
And there are other possible reasons to take Vitamin E, including its potential
blood thinning and brain-protecting powers. However, "eyes wide open" I
always say, and I don't believe most guys want to take anything that will lower
their testosterone. Most of us are looking for the opposite!
I should mention, though, that the picture is
not quite as clear as we might like. In the above study, testosterone was
not the only hormone that decreased with Vitamin E (alpha tocopherol):
androstenedione, estrone and SHBG all did as well. Now this brings up an
interesting point: the decrease in SHBG will tend to offset the loss in
testosterone by raising the percentage of free testosterone that is available to
tissues. However, no measures of free testosterone were presented in the
study so I cannot comment.
To further muddy the waters, there was also a study that showed that testosterone
levels were actually increased with megadoses (438 mg/day) of Vitamin E. 
However, this study had no control. Plus,. I would urge caution at megadosing
alpha-tocopherol, because yet another study showed a
decrease in thyroid hormones with megadosing.  One study even showed a
slight risk in lung cancer for those taking Vitamin E. 
As always your safest approach appears to be to stay within normal physiological ranges,
i.e. get your tocopherols from a standard diet. This should optimize your
hormone levels and protect your Leydig cells. (Testosterone production generates
considerable free radicals and Vitamin E can protect your cells from damage.)
NOTE: All the studies on Vitamin E use alpha
tocopherol. Both our diet and our bodies actually contain several different tocopherols,
including the important gamma tocopherol, and
you will find the best supplements include a natural blend of "mixed
The Prostate, Jan 2001, 46(1):33–38, "Effects of long-term ?-tocopherol
supplementation on serum hormones in older men"
2) Theriogenology, Feb 2000, 53(3):751-760, "Effect of ?-tocopherol on plasma
testosterone and plasminogen activator activity or inhibition in ram
3) Mol Cancer Ther, August 2003 2:797, "Androgen Antagonist Activity by the
Antioxidant Moiety of Vitamin E, 2,2,5,7,8-Pentamethyl-6-chromanol in Human
Prostate Carcinoma Cells"
4) Endocrinol Jpn, 1982, 29:287-292, "Effect of vitamin E on function of
pituitary-gonadal axis in male rats and human studies"
5) Am J Clin Nutr, 1978, 31:831-837, "Study on the effect of mega-Vitamin E
supplement in man"