[Based on correspondence with you here at MoreLife Yahoo in previous years,
Marc, I am going to assume that you are interested in increasing your libido,
rather than your testosterone per se. Yes, increasing testosterone may increase
libido, but it may also not do this and many people with rather low testosterone
can still have high libido. It would help if you would provide the values of
recent tests for free and bound testosterone and for estradiol and sex hormone
binding globulin, if you have them. --Paul]

[I have a bit low testosterone for a male of my age according to my blood test
results earlier this year, yet I have very high libido -°Olafur]

[Later note: Mark has since sent me his test results. My opinion of them is that
they verify that low testosterone is not the major source of his problem
(although more would likely help). --Paul]


Among the dietary supplements that might help to keep T up as the
years go by, I know of :

ZMA : it seems this one would bring T up if low to begin with, or if
you will, if one is zinc deficient. But there's no way this will
boost Testosterone above physiological levels--anyway I have no use
for supraphysiological levels, as too much of anything isn't good,
just like not enough is.

[I was aware of the ZMA formula, which is basically a patented formula
containing a combination of zinc and magnesium and pyridoxine, but I have never
seen any research on that particular formula and did not find any doing a search
on pubmed. Also a search on pubmed for "zinc magnesium testosterone" yields only
a few hits non of which involves the effects of zinc in combination with
magnesium on testosterone levels. However there are some studies that suggest
zinc may help increase testosterone levels although as you state it probably
only does so in those who are deficient in it (PMID: 16648790, 15054912).
-°Olafur]

[I think zinc is generally more beneficial for sperm health and fertility than
it is for testosterone or libido (other than it also being good for general
health and vitality). --Paul]


Tribulus Terrestris : The only study I know of done on this one
which may have some value (and it's sketchy because the Bulgarian
manufaturer of Tribestan conducted the study back then--a vested
interest is suspected here. I've heard of one anecdotal account from
one of the poster at :http://www.mindandmuscle.net/forum/ who told
me he got on Tribestan after a steroid cycle, and his LH/FSH got so
high that it got his PCP concerned, and he sent him to have an MRI
done--all normalized after he stopped taking Tribulus.

[The evidence for TT as a testosterone enhancer appears to be pretty weak. F.ex.
in PMID: 15994038, the most recent study I found on the effect of TT
supplementation on testosterone levels, TT supplementation had no significant
effect on testosterone levels in young men. -°Olafur]


However
Tribulus Terrestris has other health benefits other than it'S
alleged Testosterone boosting abilities--I won't mention those here,
as it would be off topic, and Paul knows very well what are the
other benefits I'm talking about here.

[Actually since I take TT it would only be off the topic of this particular
post. However, I am not sure to which other health benefits you are referring,
so you should definitely list what you think they are. --Paul]


DHEA : While DHEA may have some sexual benefit, namely increasing
libido. In males it's rate of conversion to Testosterone appears to
be low, and not much benefit towards this end.

[A recent study (PMID: 16487434) posted on the newsgroup sci.life-extension
found that for 24 men aged 58-68 giving 50 mg of DHEA at bedtime raised their
testosterone by 33.3%. Most people have been suggesting that DHEA is best taken
in the AM (and that is what I have been doing), but I have therefore recently
changed it to the PM. You might consider that also, although 50 mg is likely too
high a dosage at your age and you might be better taking only 25 mg. I will
likely also be changing my pregnenolone to the evening also, but I first want to
try the DHEA alone to see if it has any negative effects on my sleep. --Paul]


Eurycoma Longifolia Jack : The latest I read about this one is that
it won't boost Testosterone above physiological values, however it
appears it can keep it up, or bring it up if low to begin with. The
German journalist Serge Kreutz appears to be big on this herb.

Allow me to paste a quote from :

''Unfortunately, there are very few specific feeding studies in
athletes or dieters – which are perhaps the key customers for
eurycoma-based products. We are aware of only 2 US-based research
trials of eurycoma in endurance athletes (in mountain bikers,
presented at the International Society of Sports Nutrition, ISSN,
Annual Scientific Meeting in 2006) and dieters (in moderately
overweight subjects, presented at the North American Association for
the Study of Obesity, NASSO, in 2006). These studies used 50-100mg
of eurycoma and found a maintenance of normal testosterone levels in
the supplemented dieters (compared to a typical drop in testosterone
among non-supplemented dieters) and the supplemented mountain bikers
(compared to a typical drop in non-supplemented riders).''



Testofen : With regards to this one, I've found this link from the
LEF :
http://search.lef.org/cgi-src-bin/MsmGo.exe?grab_id=0&page_id=2409&query=testofe\
n&hiword=testofen%20

This compound seems promising, at least from what little info I've
read until now.


There's also Chasteberry who's of benefit too--here's a quote from
Supplement wathc :

''Chasteberry (Vitex agnus cactus) may help normalize hormonal
balance (testosterone, estrogen, prolactin) in both men and women –
an effect which may lead to increased erectile function and sexual
performance.''

Now it may look as though I already know much about the above query,
however I wanted to submit this info to Paul's scrutiny--when Paul
has reviewed this post, I'll know that whatever substance(s) comes
out as being useful towards the end of this post's query is of
value. In other words, I don't want to spend money on worthless
supplements.

If I have made oblivious omission of natural substances with the
power to help keep T up, then I'd like Paul to mention them.

Marc Boucher
34 years old
Riviere-du-Loup
Qc, Canada

[Mark, you have done a good job in researching this subject, far better than
when you first corresponded with me several years ago and I commend you for the
positive change and progress you are making. Since there has not been a great
deal of research about whether or not particular supplements increase
testosterone and some things may work for some and not for others, I think that
it is probably best to try all of those that you have listed. Remember that
there is a major difference between libido, erectile function, sexual
performance and fertility, so supplements that affect one may not affect
another. One that you did not mention which has some proponents is chrysin,
which apparently has some aromatase inhibiting properties.

In addition, you should be aware that the major driver of libido is not
testosterone directly but instead its metabolite dihydrotestosterone (DHT) which
from the tests that you sent is definitely low and may be the major factor
behind your low libido. While raising testosterone should also raise DHT, there
may be other reasons why your DHT is low even though your testosterone is only
slightly low. Are you taking anything that would be an androgen-5
alpha-reductase inhibitor, such as something for balding or for prostate health.
If so, then you might try temporarily terminating usage of these to see if that
helps and then if it does, do more research in that area and enable yourself to
make a decision on the best overall strategy since they are in some conflict
with one another. --Paul]