US Pharm. 2013;38(10):13-14.
Testosterone is a hormone produced in the testicles. Low
testosterone, often referred to as “low T,” is defined as a testosterone
blood level that is below the normal range for an adult male. Low
testosterone levels are caused by hypogonadism, a condition in which the
testicles do not make enough testosterone. Hypogonadism can occur at
any age, often as a result of infection or testicular injury. It may
also be due to a problem with the pituitary gland, which under normal
circumstances stimulates the testicles to make testosterone. There are a
number of other conditions that can result in low testosterone levels.
Because of intense marketing of treatments for low testosterone, more
men are visiting their doctors to request testosterone replacement
Testosterone Levels Decline as a Man Ages
Testosterone is responsible for many masculine physical traits,
including muscle mass and strength, sperm production, sex drive, bone
strength, and red blood cell production. Testosterone levels rise during
puberty, peak at around 30 years of age, and slowly decline with age.
It is not abnormal for testosterone to drop below the normal range once a
man reaches his 70s.
Causes of Low T
Conditions associated with low testosterone include infertility,
erectile dysfunction, bone fragility, and weak muscles. Although not
every man with low testosterone has symptoms, the most common complaints
are fatigue, low sex drive, hair loss, and problems concentrating.
Other conditions, such as thyroid disorders and depression, have similar
symptoms. A laboratory test to measure testosterone in the blood will
determine whether the symptoms are due to low testosterone.
A number of other conditions can cause testosterone to fall below
normal levels, including other hormone imbalances, testicular cancer or
cancer treatment, genetic conditions, infection, injury to the
testicles, obesity, type 2 diabetes, heavy alcohol use, liver disease,
and HIV/AIDS. Drugs such as spironolactone, digoxin, and steroids can
decrease testosterone. If testosterone levels are low, the cause should
Treatment of Low T
If a healthy young male has a low testosterone level, the cause can
be corrected or testosterone can be prescribed. Testosterone levels
commonly decline with age, so there is considerable debate about whether
to prescribe replacement therapy for older men with low testosterone.
If the testosterone level is very low, a man is at risk for weakened
bones (osteoporosis), but testosterone supplementation to prevent
fragile bones is controversial. The use of testosterone supplementation
in older men with normal testosterone to restore the masculine traits of
their youth is even more controversial. There is no clinical evidence
that testosterone has a positive effect in these men, so its use cannot
be routinely recommended.
If deemed appropriate, testosterone may be supplemented with a
prescription-only product. A variety of dosage forms are available. For
example, testosterone may be given by injection every few weeks. There
is also a tablet-shaped patch (Striant), known as a buccal tablet,
that is placed on the front upper gum under the lip, where it slowly
releases testosterone over 12 hours. A testosterone skin patch, topical
solution, and gel are available for daily skin application. The solution
and gel formulations must be thoroughly washed from the hands to avoid
skin-to-skin contact and transfer to others. Another product is
Testopel, which consists of tiny pellets that are implanted under the
skin and slowly release testosterone over 3 to 6 months.
The side effects of testosterone replacement therapy include enlarged
breasts, enlarged prostate, acne, and increased red blood cell
production. Men with prostate cancer are usually not candidates for
testosterone therapy, and men with breast cancer should not receive
Sales of herbal testosterone “supplements” or “stimulants” have
skyrocketed as men attempt to regain their youth using these
“all-natural” products. Unfortunately, these products have not been
studied carefully for safety or effectiveness.
If you have questions about prescription testosterone products and
their proper use, your pharmacist can help. Your pharmacist can also
tell you about natural products or supplements that are marketed to
treat “low T.”