Free Testosterone and SHBG
A lot of guys don't realize that it is really only free testosterone that counts.
I mostly talk about total testosterone because that's what doctor's mostly talk
about. But, in reality, the only purpose in having a nice, beefy total
testosterone number is to provide your tissues with nice, beffy free
testosterone number, since that is the only testosterone number that will really
make a difference in your life.
Why is free testosterone the only testosterone that does your body any good?
The reason is that non-free, or bound testosterone is actually chemically bonded
to a protein called Sex Hormone-Binding Globulin, or SHBG for short. Once
testosterone is bound it is no longer bioavailable to do all those wonderful
things for our brains, blood, muscles and sex lives that we as males so highly
value.
SHBG is controlled and produced in the liver primarily by androgens (and
thyroxine). Normal aging, as many of us know all too painfully, leads to
substantial drops in androgens such as testosterone and a corresponding rise in
SHBG. This is about as vicious of a endocrinological cycle as one can come
across: decreasing testosterone leads to increasing SHBG, which leads to
decreasing free testosterone and so on. No wonder some of you feel like
crap!
Do you know the foods and drinks that increase erection-boosting
Nitric Oxide? Check out the
Peak Erectile Strength Diet where I show
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So how do you know if your free testosterone is low? It starts with a
simple test from your doctor. You sometimes have to ask for this, as some
doctors just stick with total testosterone. Generally, free testosterone
is given as a percentage of total testosterone, the typically acceptable range
according to the lab listed as 1.5%-2.9%. Work with your doctor on this,
but I like to see at least 2%. In my opinion, if you are below 2%, then
you may want to take Stinging Nettle and see if that boosts this all important
number.
Let me give you some of the most important ways to control SHBG and Free
Testosterone:
1) Estrogen. You must keep your estrogen levels in check. Research
shows that normal aging as well as an increase in adipose - that's a nice way of
saying fat - tissue leads to ever increasing levels of estrogen. And here's the
key: increasing estrogen leads to increasing SHBG. Please read the
important link on
How to Control Estrogen.
2)
Testosterone. Low testosterone levels will tend to raise your SHBG as
well. Yes, that's called a vicious circle. Read this link on
How to Raise Testosterone Naturally if you have
not already.
3) Medications and Alcohol. Many medications can effect SHBG. Remember that SHBG
is made in the liver and most medications effect the liver. Common drugs
that often raise SHBG are sedatives, antihypertensiaves, tranquilizers as well
as your old friends beer and booze.
4) Stinging Nettle. Another way to lower SHBG is through an herb called Stinging Nettle.
Stringing Nettle is widely prescribed in Europe for BPH (
Benign Prostate
Hypertrophy). Several studies have documented Stinging Nettle's
SHBG-lowering powers [2] and, so far, Stinging Nettle has an excellent safety
profile. However, its side effect profile is worth mentioning:
Stinging Nettle also blocks the action of the enzyme that converts testosterone
to DHT. This seems good since DHT is associated with things like hair loss
and prostate problems. However, sometimes, in sensitive individuals, side
effects include erectile dysfuntion and a decreased amount of semen.
I should point out that there are no studies, as far as I know, that
actually show Stinging Nettle increasing free testosterone: it is just
something that has not been studied.
5) Insulin Resistance. Insulin resistance will lower your SHBG
[1]
and, therefore, in the short term probably raise free testosterone. So
let's all get insulin resistant and live happily ever after, right? Wrong!
Insulin resistance is a death warrant. (Read this link
on
Metabolic Syndrome for more details.)
6) Sugar and Corn Syrup. These bad boys can lower SHBG.
Unfortunately, these can lead to insulin resistance, inflammation, advanced
glycation end products and many other nasty things. How does it do all
this?
Researchers have discovered that sugar will also lower SHBG, because it
increases fat synthesis in the liver, which in turn shuts off the gene involved
in SHBG synthesis. Bottom line: stay away from sugar and corn syrup
even though in the short term they may raise your free testosterone.
7) Green Tea. Green Tea does actually raise SHBG. However, it's
health benefits are so overwhelming that I highly encourage you to drink it
anyway.
8) Vitamin D. Vitamin D was found in a 2009 study of about 2,300 adult
males to lower SHBG and increase both free and total testosterone. [3]
2) Planta Med, 1995 Feb, 61(1):31-32; Fortschr Med, Nov 10 1996, 114(31):407-411;
Z Naturforsch [C], 1995 Jan-Feb,50(1-2):98-104
3) Clin Endocrinol (Oxf), 2009 Dec 29, [Epub ahead of print], "Association of
vitamin D status with serum androgen levels in men"
