Not enough test in testosterone
Not enough test in testosterone
(This article was first printed in the April,
2004 issue of the Harvard Heart Letter. For
more information or to order, please go to http://health.harvard.edu/heart.)
More and more men are turning to testosterone
therapy even though little is known about its
effects on the heart and long-term health.
If aging causes a gradual droop in a man’s
production of testosterone, can boosting levels
of this hormone restore youthful vitality, or
at least slow aging and prevent the diseases
that come with it? The million or so men now
taking testosterone certainly hope so.
By age 60, about one in five men have testosterone
levels below what’s normal for young men.
Whether their levels are too low for men of their
age is still a big unknown. Having less testosterone
in the bloodstream could protect men against
prostate cancer or other testosterone-related
diseases. It could also pose problems.
Testosterone, sometimes erroneously called the
male hormone (women’s bodies make it, too)
affects much more than a man’s sex drive,
hair pattern, and prostate. It helps build muscle
and metabolize fat. It strengthens bone. It can
also boost energy and mood, and may play a role
These possible benefits, coupled with the siren
song of looking and feeling younger, are calling
a growing number of older men to try testosterone
therapy. For those whose bodies make too little
of the hormone, it’s the right thing to
do. For everyone else, testosterone therapy is
an unplanned, uncontrolled, unsupervised experiment.
We say this because no one knows if extra testosterone
improves health or well-being in men with normal
or low-normal levels of the hormone. More alarming,
there’s no clear picture of the hazards
(see How taking testosterone could affect
the body). How testosterone therapy affects
the heart, blood vessels, and circulation is
another gray area.
taking testosterone could affect the
- Increased muscle
- Increased strength
- Increased energy
- Stronger bone
- Improved mood
- Improved sexual function
- Prostate enlargement
- Prostate cancer
- Sleep apnea
- Breast swelling
- Excess red blood cells
Hormones and the heart
For years, testosterone was blamed for the earlier
appearance of heart disease in men than in women.
Yet studies now suggest the opposite possibility:
that testosterone could be good for men’s
hearts. Some studies, but not all, have linked
higher testosterone levels with higher levels
of HDL (good) cholesterol, lower blood pressure,
better natural clot-busting ability, greater
sensitivity to insulin, and less inflammation.
Men with more testosterone seem to be less likely
to develop atherosclerosis (the process leading
to cholesterol-clogged arteries) and diabetes
than men with lower levels.
Among men with too little testosterone, regular
doses that bring the hormone into the normal
range don’t harm cholesterol levels or
blood pressure. Some small but intriguing studies
suggest that testosterone therapy can improve
the flexibility of arteries, ease activity-related
chest pain (angina), and improve heart function
among men with heart failure.
Lessons from women
If this paints a positive, why-not-start-today
picture of testosterone therapy, the flip-flop
on hormone therapy in women should raise a red
During the 1990s, women were encouraged to take
estrogen after menopause to help prevent heart
disease. This recommendation was based on two
consistent streams of evidence. In several studies
that followed the health of large groups of women
for up to a decade or longer, those who chose
to take estrogen had fewer heart attacks or strokes
than those who didn’t take hormones. At
the same time, smaller experiments showed that
estrogen improved cholesterol levels, blood vessel
flexibility, and natural anticlotting ability.
Yet when large trials in which volunteers took
an unmarked pill containing estrogen plus progestin
or a placebo finally got under way, women who
took the hormones had more heart attacks,
strokes, serious blood clots, and new cases of
This won’t necessarily happen with testosterone.
But we can’t be sure how this hormone affects
the heart without the same kind of randomized
trials that revealed possible problems with hormone
therapy in women.
What to do
Such trials haven’t yet gotten off the
drawing board, and the Institute of Medicine
has recommended putting them on hold. So it could
be five years or longer before the true benefits
and risks begin to firm up.
What should you do in the meantime? If you aren’t
taking testosterone, don’t start unless
your body needs it and you have symptoms that
suggest a testosterone problem. Tip-offs include
fatigue, muscle weakness, dwindling interest
in sex, osteoporosis, or a suspicious bone fracture.
A simple early-morning blood test (possibly repeated
once or twice) can tell you how much testosterone
is circulating in your blood. A low reading may
prompt your doctor to check for possible causes.
These may include problems with the pituitary
gland or the part of the brain called the hypothalamus,
both of which regulate testosterone production.
Some doctors use 200 nanograms per deciliter
(ng/dL) as a cutoff, while others use 300–400
If your testosterone is indeed low, Drs. Ernani
Rhoden and Abraham Morgentaler, from Harvard-affiliated
Beth Israel Deaconess Medical Center, suggest
some steps to take before starting therapy. They
recommend having a prostate exam along with blood
tests for red blood cells and prostate-specific
antigen (PSA, a test for prostate cancer). They
also urge their older patients to have a prostate
biopsy to check for hidden prostate cancer. These
recommendations appeared in their review of testosterone
therapy in the January 29, 2004, New England
Journal of Medicine.
Once you start taking testosterone, itR 17;s
important to monitor how your body responds to
it. Are blood levels of the hormone rising? Are
symptoms improving? Have you noticed changes
in your urination, or are you snoring more? Routine
follow-up should include rectal exams for prostate
cancer and periodic blood tests for PSA and hematocrit
(red blood cells). Because the effects of testosterone
therapy on the heart and circulatory system are
unknown, paying more attention to the warning
signs of a heart attack or stroke may also be
If you are taking testosterone even though your
level is in the normal range, there’s no
urgent need to stop. You might want to revisit
the benefits and risks with your doctor, though,
and keep alert for possible problems. In other
words, approach testosterone therapy like the
experimental treatment it is, open to the possibility
of benefit and alert for the possibility of harm.