Testosterone and Nitric Oxide
What's more important, testosterone or nitric oxide? I couldn't answer that one and I doubt you can either - both of these molecules
just impact too many functions and systems to declare a clear victor. What is important to note, though, is the INTERACTION of these two
on each other and how they partner to improve men's health in, literally, a hundred different ways. Both of these have been found by
multiple studies to impact endothelial function, i.e. nitric oxide and blood flow, sexual health, brain function, sleep, mood, exercise
and athletic performance and so on. Yes, they affect almost everything we hold dear as males.
Let's start with testosterone and its role in protecting nitric oxide. Having ample testosterone levels is a key, researchers have found,
to maintaining arterial health. I cover this in my page on Testosterone and Heart Disease.
The quick summary is that testosterone actually optimizes and even boosts
nitric oxide levels through action on eNOS, the same enzyme that Viagra works
on. Testosterone also lowers arterial inflammation
according to a couple of studies.  Its actions are so important to your
cardiovascular system that low testosterone levels have been shown to be a
significant risk factor for many chronic cardiovascular diseases, a fact I will
go into in more detail below. And this is one of the things I found so
exasperating when doctors are unwilling to treat low testosterone: they put
their male patients at risk for many nasty medical conditions, especially heart
And then let's examine the most glaring example: low testosterone tends to
accelerate hardening of the arteries and arteriosclerosis. And these
conditions can definitely affect your nitric oxide levels in the medium and long
terms. How? Simple: arteries covered with plaque cannot produce sufficient nitric oxide for things
like erections and safe blood pressure levels. Of course, there are other
problems with hardening and narrowing of the arteries - like a heart
attack or stroke! - but this limiting of
nitric oxide output is one of the symptoms that a man will generally first notice.
As many of you know, it first shows up often as erectile dysfunction. And
it is very
common in the U.S. for a man in his 40's or 50's to begin to experience the
beginnings of prehypertension/hypertension as well.
Need to boost your Nitric Oxide naturally through food, drink and supplements? Check out Lee Myer's book here:
The Peak Erectile Strength Diet
Or do you need the most comprehensive testosterone book in Amazon? Here it is:
Natural Versus Testosterone Therapy
But the point is this: low testosterone has been shown to accelerate arterial
decline, which in turn helps lead to a decrease in nitric oxide levels. So to
one degree or another, your endothelial nitric oxide may be dependent on your
All of this explains why so often on
The Peak Testosterone Forum,
I see men with BOTH testosterone and nitric oxide related issues. They
likely tend to snowball downward together. And I believe this is shown in
the studies, where a significant percentage of men given HRT (testosterone
therapy) are not cured of their erectile dysfunction, a subject that I
cover in my link on Viagra Failure.
Likewise, HRT often fails to cure erectile dysfunction on its own. One
meta-analysis, where researchers aggregate or pool studies together, showed that
about 57% of patients with erectile dysfunction responded to testosterone
therapy.  Of course, that implies that in about 43% of patients, HRT did
not really help. NOTE: My guess is that there
would probably have a higher response rate if it was properly managed, i.e.
testosterone levels were raised significantly and estradiol levels were managed
So testosterone, in particular low testosterone, can affect nitric oxide.
What about the other way around? Well, let's look at what I call The Three
Main Natural Engines of Testosterone Production. In all three cases, I will show that
low nitric oxide levels can negatively impact every one of them:
1. Sleep. Nitric oxide is VERY important to sleep and research has
shown that it is an actual regulator of your sleep/wake cycles.  It likely does
this by altering the release of the neurotransmitter acetylcholine in the brain.
To test the impact of NO on sleep, researchers gave rabbits various nitric oxide inhibitors and found
that it lowered REM eye movements.  And a study on rats showed that nitric
oxide inhibitors actually decreased the amount of time in sleep.  Sleep
researchers have noted that decreased NO will actually alter EEGs and ages the
brain in several key ways. 
2. Sexual Intercourse. Of course, sexual intercourse and nitric oxide
go hand in hand and Viagra proved that forever by putting million of men "back
in the game". Viagra works, of course, by slowing the breakdown of
endothelial nitric oxide, allowing levels to build up more quickly. One
study found that both Viagra and Cialis increased the frequency of sexual
intercourse in men by a little over 40%.  One study of Cialis usage showed
that it did, indeed, give a modest increase in testosterone and a nice boost to
the T/E2 ratio. See my link on
The Testosterone-to-Estradiol Ratio for more information.
3. Mood and Attitude. I document many cases where the mind and Testosterone
are very related. Competition and victory can very substantially raise
testosterone. Depression can lower it Once again, this ties in with
the fact that low nitric oxide
levels can definitely affect mood. In its extreme form, it has been
implicated as being a factor at times in clinical depression and schizophrenia.
 For more information, see my links on
Testosterone and the Mind and
Testosterone and Depression for more information.
So, although I do not have a study to prove it, it is very likely that low nitric
oxide can lower testosterone and low testosterone can lower nitric oxide levels
over time. Clearly this could create a viscous circle and is part
of the explanation as to how men living a Western lifestyle spiral downard in
health terms so rapidly after about the age of 40 or 45.
The good news? There is hope if you're willing to go natural, because there
are natural ways to actually reverse, or at least significantly partially
reverse these simultaneous decreases in nitric oxide and testosterone. Here are some examples:
1. Testosterone. There are literally dozens of ways to naturally
reverse some of the smaller losses in testosterone through lifestyle changes and
I have outlined these in my link on How to Increase Your Testosterone Naturally.
Now by far the biggest of these is weight loss. Men who lose massive amounts of weight can in some cases literally more than double their
testosterone levels. Some men, though, simply cannot increase the testosterone enough through lifestyle changes alone and
will have to consider HRT (Hormone Replacement Therapy). However, in my opinion if this is well-managed and well-monitored and the patient is brought to normal levels of testosterone, then this can still be considered a natural solution. The reason is that one is simply replacing testosterone that is missing from normal aging or from damage.
2. Nitric Oxide. Again, there are dozens of ways to boost your nitric
oxide. One is through consumption of high nitrate foods, something I discuss in My Review of Beet the Odds
. (This methodology is ultracritical for you 40+ men.)
Still another is through following the principles of my book, The Peak Erectile
, which is all about foods that will increase nitric oxide and
blood flow. If you go through the links listed here in my
Erectile Strength section, you will come across many other strategies as well.
I should also add that you can heal you arteries by actually reversing some of
that arterial plaque. I cover this in my link on
How to Clear Your
The important thing is that if you raise testosterone, you will also likely raise
nitric oxide levels. And, if you raise nitric oxide, you will be improving
sleep, the frequency of sexual intercourse and mood, all of which will very
likely boost testosterone. Yes, you should be able to not only
halt the decline, but actually turn back the clock significantly.
1) The Journal of Urology, Aug 2000, 164(2):371-375, "TESTOSTERONE
SUPPLEMENTATION FOR ERECTILE DYSFUNCTION: RESULTS OF A META-ANALYSIS"
2) The Journal of Neuroscience, 15 Jan 1997, 17(2):774-785, "Pontine Nitric Oxide
Modulates Acetylcholine Release, Rapid Eye Movement Sleep Generation, and
3) AJP - Regu Physiol, Jan 1, 1994, 266(1):R151-R157, "Inhibition of nitric oxide
synthesis suppresses sleep in rabbits"
4) Brain Research, Jan 1999, 816(1):209–219, "Endogenous nitric oxide in the rat
pons promotes sleep"
5) Sleep Medicine Reviews, Apr 2005, 9(2):101–113, "Nitric Oxide and sleep"
6) BJU International, Dec 2005, 96(9):1323–1332, "An open-label, multicentre,
randomized, crossover study comparing sildenafil citrate and tadalafil for
treating erectile dysfunction in men naïve to phosphodiesterase 5 inhibitor
7) Neuroscience, Jan 1998, 83(3):867–875, "Nitric oxide synthase-containing
neurons in the human hypothalamus: reduced number of immunoreactive cells in the
paraventricular nucleus of depressive patients and schizophrenics"
8) Mol. Hum. Reprod, 2010, 16(10):761-769, "Endothelial regulation of eNOS, PAI-1 and t-PA
by testosterone and dihydrotestosterone in vitro and in vivo"