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Q: free and total testosterone levels. ( Answered,   1 Comment )
Subject: free and total testosterone levels.
Category: Health > Men's Health
Asked by: gapgapgap-ga
List Price: $25.00
Posted: 12 Oct 2002 08:08 PDT
Expires: 11 Nov 2002 07:08 PST
Question ID: 75721
I have serum testosterone of 452. I am a 39 year old white male. The
refrence range is 241-827. I have  a free testestorone of 4.02 the
refrence range is 1 - 2.70. What can this mean. I have an igf1 of 417
the refrence range is 114-492. Could I be producing too much
testosterone and its bieng converted to estrogen. My erections arent
as hard or as frequent as they were 1 year ago. Any help ?
Subject: Re: free and total testosterone levels.
Answered By: richard-ga on 12 Oct 2002 09:03 PDT
Hello and thank you for your question.

As you may have discovered in your own Internet search, one of the
factors implicated in the decline of free testosterone levels is
excessive binding of testosterone to carrier proteins that divert it
for use in the production of other proteins/hormones, including
estrogen.  The therapy that directly addresses this situation is
testosterone replacement, but there is some controversy about whether
testosterone replacement correlates with increased risk of prostate
cancer.  Obviously you should consult with a qualified urologist about
whether that route is appropriate for you at this time.

"Testosterone within the circulation is principally bound to proteins,
the most important of which is sex hormone binding globulin (SHBG).
Only about 2 percent of testosterone is unbound (bio-available) and
therefore free to enter cells in order to effect its biological
actions by binding to androgen receptors...."
"Hypotestosteronaemia levels [that is, low levels] quoted in papers
vary between around 300 ng/dl (10.4 nmol/L) and 400 ng/dl (13.9

"Bioavailable testosterone refers to the 'free' portion of the hormone
unbound to carrier proteins which is able to act directly upon target
Sexual Dysfunction and Male Hormones

"It is well known that androgen levels decline in men with age.
Furthermore, as a result of the increase in binding capacity for
testosterone in serum, there is an early and more dramatic decline in
free testosterone, the physiologically functioning component of serum
testosterone, than in the total testosterone concentration...."
"The ideal therapy should consist of creating physiologic testosterone
concentrations (400 to 700 ng/dL in blood taken in the morning) and
restoring circadian variations."
Hormone Replacement Therapy for Aging Men

Since your score is higher than the 300-to-400 range that normally
merits treatment, you are still within the 'normal' range, albeit at
the low end of it.  So you should look before you leap into a course
of treatment.

The following article talks about estrogen conversion and hormone
replacement, but I think it's a bit over-entusiastic in its promotion
of the treatment:

Not to scare you, but here's one more thing that you should be aware
"Of great interest is a recent finding that men with coronary artery
disease have significantly lower levels of plasma testosterone than
controls and that intracoronarv testosterone infusion in men with
coronary artery disease increases coronary blood flow. Such findings
suggest that age related declines in testosterone in men may be
associated with heart disease ...."

So besides discussing hormone replacement with a urologist, if you
haven't had a general physical in the last few years you should do
that too.

Search terms used:
free testosterone serum decline

I hope you find this information useful and responsive to your
question.  Of course you should not consider this answer as medical
advice (and I'm not a physician).


Request for Answer Clarification by gapgapgap-ga on 12 Oct 2002 10:12 PDT
You may have misunderstood my question. My free testosterone is almost
2 times higher than it is supposed to be while my total is at the low

Clarification of Answer by richard-ga on 12 Oct 2002 12:53 PDT
Hello again.

My answer focused on the 452 total score because that is somewhat in
the low range and is consistent with the symptoms you describe.

Is the 4.02 figure that you gave a calculation of your Free Androgen
Index (FAI)?  I assume it is, because my research indicates that FAI's
reference range is 1.6 to 2.9.

If it is your FAI that is being reported to you, you need not be
concerned.  Normal SHBG levels vary widely.  The data given below puts
the SHBG range at 13 to 71 nmol/L .  Because SHBG is the denominator
of the fraction it generates wide swings in FAI values.

"The FAI is the ratio of total testosterone to SHBG. It provides a
simple assessment of physiologically active testosterone.
FAI = 100 x TT (in nmol/L) / SHBG (in nmol/L)"
Reproductive Endocrinology

Free Testosterone (Bioavailable Testosterone):
Adult Male Reference Interval
Free Testosterone:  47.0-244.0 pg/mL   
% Free Testosterone: 1.6 - 2.9%
20 - 39 years:
 400 - 1080 ng/dL
40 - 59 years:
 350 - 890 ng/dL
60 years and over: 
 350 - 720 ng/dL

Sex Hormone Binding Globulin [SHBG]:
13 - 15 years  
  13 -  63 nmol/L
16 - 18 years  
  11 -  54 nmol/L
19 - 150 years 
  13 -  71 nmol/L

Male Hormones

"Measurement of free androgen index (FAI) is a method sometimes used
to measure free testosterone levels. There is much difficulty in using
this as a measurement of free testosterone in men as the FAI was a
method designed for use in women. The reference range appears to
differ widely across Australia. There does not seem to be a reason for
this variation."
Male Hormones

Please confirm what units your figure for free testosterone has been
calculated in.  If it is something other than FAI, I will take another
look at it.


Request for Answer Clarification by gapgapgap-ga on 14 Oct 2002 07:00 PDT
Sorry once again I made a mistake I have a free testosterone count of
18.17 out of a range of 5 - 21. My ratio of free to total was 4.02
which was almost 2x as high as normal. What can you find out about
this ?

Clarification of Answer by richard-ga on 14 Oct 2002 15:42 PDT
Hello again:

I think it's best to look at the serum testosterone and free
testosterone figures separately.

You report serum testosterone of 452, free testosterone of 18.17, and
18.17/452 = 4.02% free.

The reference range for serum testosterone is 241-827 (this source
says 350-1030 with a mean of 627 over ages 20-50); the reference range
for free testosterone is 5-21 (this source says 5.2-28); and the
reference ratio is 1-2.7 (this source says 1.5-3.2).
(page 36-37)

I really think you shouldn't worry about the ratio.  True, your serum
number is a little on the low side and your free number is a little on
the high side.  But to say your ratio is twice as high as normal
exaggerates the effect.  Here's an arithmetical example.  Say a ratio
of 2.5%  is 'normal', and arises from a ratio of 12.5/500.  If you
couple a 30% increase to the numerator with a 30% decrease to the
denominator, the fraction becomes 16.25/350 or about 4.6%.

So there's nothing unusual about your numbers.  As for your symptoms,
a visit to a urologist would still be a good idea.

Subject: Re: free and total testosterone levels.
From: dani32-ga on 17 Feb 2005 15:04 PST

I am a 30 yr old male and have experienced hot flashes now for about
3.5 months. I have seen my regular PCP who did all the bloodwork and
found absolutely nothing. I have gone to an endocrinologist who has
repeated all the bloodwork, has ordered a 24 hr urine 5hiaa, and an
octrioscan, and still nothing.

My testosterone level is 334 ng/dL and free test is 2.4% or 80.5pg/mL. 

Do you believe I could suffer from Hypogonadism? If yes, what should I
do to convince my doctor that he should give me the proper treatment?

Many thanks for your reply.

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