have you ever wondered what the normal
testosterone level is for your age I'm
Dr Reena Malik urologist and pelvic
surgeon and today we're going to review
some new research digging into what
testosterone levels are on average for
men between the ages of 20 and 44 so
according to the American Urological
Association low testosterone levels are
less than 300 nanog per deciliter and in
order to officially diagnose low
testosterone you have to have two serum
total test testosterone levels in the
early morning and we say early morning
because among men with traditional sleep
patterns mean you usually sleep between
10: p.m. and 6:00 a.m. your Peak
testosterone values occur between 3: and
8:00 a.m. and those levels tend to
decrease quite significantly throughout
the day particularly they've looked at
total testosterone levels at 400 p.m. in
men who are 30 to 40 years old and they
found that they're 20 to 25% lower than
measurements taken at 8:00 a.m. and why
do you take two well that's because
there's really significant variability
between testosterone levels even if
they're from you and this has actually
been shown in research that repeat
testosterone levels can vary between 65
to
153% between tests and when you use two
measurements this is actually reduced to
somewhere between 30 and 43% the problem
with this 300 NR per deciliter value is
that it was dery from testosterone
Replacements trials that were done in
men above the age of 45 also we we know
that testosterone levels decline with
age and lastly cffs vary depending on
the society you're looking at so while
the American neurological Association
says 300 there are societies that go as
low as 200 and societies that say cut
offs are as high as 350 nog per
deciliter so I know in my practice
there's tons of young men who come in
talking to me about having symptoms of
low testosterone and what are those
symptoms well they can be fatigue low
sex drive difficulty with erections
having reduced muscle mass maybe losing
some armpit or pubic hair or noticing
that the testicles are smaller than
usual or even having hot flashes some
guys will also have depression or
difficulty with concentration and memory
or even notice that their breast tissue
is enlarging so these are serious
symptoms right and really bothersome to
a lot of people so in these young guys
I'll often check their testosterone and
get a level somewhere between 300 and
400 nog per deciliter now while that's
considered normal over overall it might
not actually be normal for them and
we've never really had great data to
discuss what exactly is expected to be
normal for them and now we do so in this
study a group of researchers pulled data
from the national health and nutrition
examination survey and this is a survey
that looks at a sample of people from
around the United States that's supposed
to be representative of the national
demographics meaning that they are the
same kind of age breakdown the same
racial breakdown and many other factors
so they looked at this survey from from
2011 to 2016 and in this survey they can
gain all sorts of information including
interviews physical examination values
and laboratory tests so they
specifically picked men between the ages
of 20 to 44 who underwent an early
morning testosterone level somewhere
between the times of 6:00 a.m. to 10:00
a.m. and then they broke down these men
into 5year age groups meaning 20 to 24
25 to 29 and so on and so forth up to 40
to 44 and pulling all the data they got
to about 1,500 men whose average age was
about 32 years old so what did they find
well they found that in the 25 to 29
year age group that the mean
testosterone was the highest the average
testosterone that was 514 nog per deer
and when you look at those who were 40
to 44 group was the lowest of 430 nog
per deiler they also found that for
every single year you age they saw a
decrease in testosterone of 4.3 nanog
per deciliter and then they decided Well
how do we do age specific cut off for
low testosterone well when they looked
at the American neurological Association
guidelines they looked at tertiles
meaning if you broke up the men in a
certain age group the first third of
them would have testosterones at this
level the next third would have them in
this level and the last third would have
them in this level and it was kind of
like a bell curve with the majority of
the people being in the middle tertile
and so they looked at their data in the
same way to decide what would be a age
specific cuto so they found that the age
specific cut off starting from 20 to 24
year- olds all the way to 40 to 44 year
olds was 409 413 359 352 and 350 so this
is a great starting point for a
discussion about what is considered
normal in your age group and where is
kind of the beginning of normal
considered however this is not a perfect
study and there are some limitations one
is that we don't know if the men in the
study actually had low testosterone
because they didn't actually look if
they had symptoms of low testosterone so
you would imagine that if you're getting
a representative sample of the United
States there will be several men who
have low testosterone in fact that may
mean that the cut off is actually a
little bit higher if you look at only
men who don't have low testosterone
symptoms secondly the N Hayes database
only got one serum testosterone level
and we know that if you have an abnormal
testosterone level 30 to 34% of those
men will have a normal testosterone
level over the next 24 hours so you're
kind of overdiagnosing maybe a third of
people with low testosterone so in Ideal
World you get both those numbers and
maybe average those or look at the
highest number to get a true normal
value so while this is interesting and
useful if you are having low
testosterone symptoms please make an
appointment with your doctor your
urologist your endocrinologist to
discuss what this means and if you are
candidate for treatment for low
testosterone and that doesn't always
mean getting testosterone it may mean
doing a host of other things so I've
talked about low testosterone many times
in the past including what to do to
boost your testosterone levels what
testosterone replacement therapy is and
how it works symptoms lots of stuff so
check out my testosterone playlist to
learn more if you've enjoyed this video
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