What is Testosterone?
Testosterone is the most important sex hormone in the male body,
and it plays a key role in keeping men physically and psychologically
healthy.
Key roles for testosterone include:
• Maintaining sex drive, sexual function and sperm production
• Increasing muscle mass
• Maintaining mood and energy levels
• Stimulating development of the penis and testes
• Growth of facial and pubic hair
• Deepening the voice
The male body makes testosterone primarily in the testes (95%)
and in the outer layer of the adrenal glands, called the adrenal
cortex (5%).
Under normal circumstances, the body carefully controls the production
of testosterone. Chemical signals from two glands in the brain
- the pituitary and hypothalamus - tell the testes how much testosterone
to produce.
The hypothalamus controls hormone production in the pituitary
gland by means of gonadotropin-releasing hormone (GnRH). This
hormone tells the pituitary gland to make luteinizing hormone
(LH). LH orders the testes to begin producing testosterone. If
the testes begin producing too much testosterone, the body sends
signals to the pituitary gland to make less LH. This, in turn,
slows down the production of testosterone. If the testes begin
producing too little testosterone, the body sends signals to the
pituitary gland telling it to make more LH, which causes the testes
to make more testosterone.
Testosterone replacement therapy: Effective treatments are available
In men whose testicles fail to produce sufficient
amounts of the hormone testosterone (hypogonadism), testosterone
replacement therapy (TRT) may restore sexual function, improve protein
metabolism and prevent bone loss. In addition, men receiving TRT
often experience an increase in energy and libido and an improved
sense of well-being.
In the past, men requiring testosterone replacement
had one option — injections. But new therapies developed in the
last decade give men with significantly low testosterone more options.
Testosterone delivery methods
The safest testosterone delivery methods for adult
men are intramuscular injections and absorption through the skin
using patches and gels. Taking testosterone orally is now rare because
it may worsen your blood cholesterol levels and increase your risk
of blood clots, heart disease and liver disease.
Injections
Intramuscular testosterone injections (testosterone
cypionate and testosterone enanthate) are effective, safe and inexpensive.
The shots are given about every 2 weeks. You may experience fluctuations
in symptom relief because the level of testosterone varies between
doses.
Patches
- Scrotal patch (Testoderm). Thin scrotal skin is much more absorbent
than other skin sites. Apply the scrotal patch in the morning
and remove it for bathing and intercourse. Itching and skin irritation,
which can occur in a small percentage of people, are usually very
mild and diminish with continued use.
- Nonscrotal patch (Androderm). Apply the nonscrotal patch as
directed to such areas as your back, abdomen, arm or thigh. You
might experience a skin reaction to this product.
The most recent advance on the market is testosterone
gel. You rub the gel onto your upper arm, shoulder or lower abdomen.
It's possible to transfer the testosterone from your skin to your
partner's since there is no barrier, as there is with patches. To
avoid this, cover the area and avoid skin-to-skin contact for approximately
5 hours after application.
Choosing a preparation
You and your doctor have many options for TRT.
Choosing a therapy depends on your acceptance of a particular delivery
system, its side effects and its cost.
If you or a family member learns how to administer
the injections, the intramuscular testosterone shot is the least
expensive and perhaps safest therapy. The cost is higher if a nurse
or doctor gives the injections.
The scrotal patch has a low rate of skin irritation
but must be removed for bathing and intercourse. Nonscrotal patches
are more expensive.
Gels offer a convenient option, but they're also
the most expensive. Skin reactions are uncommon.
All of these preparations are effective, so choosing
one over another often comes down to your individual preference,
convenience and cost.
Hypogonadism and aging Studies evaluating testosterone treatment
in hypogonadal men suggest improvement in muscle mass, bone mass,
strength and sense of well-being. But should TRT be considered for
testosterone loss from normal aging?
"There are a lot of good data that define
the risks and benefits of estrogen replacement for women,"
says Todd Nippoldt, M.D., an endocrinologist at Mayo Clinic, Rochester,
Minn.
"We're just getting that sort of data on men
now (regarding testosterone). It's unclear if it's beneficial to
raise testosterone levels that have declined because of normal aging."
Many questions remain unanswered, particularly
the extent and the duration of beneficial effects, the number of
men who will benefit and the long-term risks. Risks may include
an increase in cardiovascular disease, benign and malignant prostate
disease, and sleep apnea. If a disease is the cause of low testosterone,
TRT may be right for you. At this point, there is not enough evidence
to recommend using TRT to compensate for the gradual decline of
testosterone due to normal aging.
See your doctor for advice about your specific
situation.
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