Thanks for coming to Google with your questions. First off, I'd like
to emphasize I am not a physician, and the information here is not
meant to advise you; I hope to inform you of the options for
testosterone replacement and the reported advantages and risks of each
so that you and your physician can make the right choice for you.
As you requested, I have consulted medical journals where appropriate.
In cases where non-technical medical literature put the case more
succinctly or in lay terms, I have used those references. I might add
at the outset that UK practices do not differ from international
endocrinological practice so I also use reputable sources from other
Testosterone replacement therapy has been in use for over 30 years to
treat various types of male hypogonadism. Hypodonadism is
characterized by testosterone levels below the normal range. Symptoms
can include tiredness, reduced libido and depression.
Therapy with testosterone is considered medically safe. The positive
effects of the therapy are on mood, energy levels and libido. It can
also result in increased muscle mass, increased body weight, an
increase in lean body mass and a decrease in fat. There can also be a
decrease in cholesterol levels. All modes of therapy are effective in
restoring function and well-being.
On the negative side, testosterone therapy has an adverse effect on
prostate in men who already have prostate cancer. It may also be
associated with azoospermia (absence of sperm) , lipid (fat)
abnormalities, polycythemia (increased red blood cell count), sleep
apnea, and the potential for prostate changes.
The current "GP Handbook-A UK medical encyclopedia on the World Wide
Web" lists any of the following as acceptable modes for testosterone
* oral testosterone (three times daily)
* intramuscular testosterone injection (at intervals of around 3 weeks)
* subdermal testosterone implants (which last 4-6 months)
* transdermal testosterone patches (replaced every 24 hours)
These modes of delivery are also cited in the clinical guidelines of
the American Society of Clinical Endocrinologists, for one,
) and are considered acceptable medical practice everywhere.
All modes accomplish the primary goal of replacement therapy: they
restore normal levels of testosterone and sexual function. For the
most part, side effects are not a major problem. The following list
shows the various modes (with references below each entry):
How is it done: In this mode of testosterone delivery "testosterone
esters are deposited deep into muscle by injection.
How often: One injection will last two to three weeks.
Advantages: The low cost of treatment.
Disadvantages: "some patients experience an unpleasant
'roller-coaster' effect as levels rise and then fall dramatically.
[Also,] the injections can be painful, although many men do get used
to them and can administer treatment themselves," although some men
experience anxiety about the injections. Sometimes there can be
INJECTION, LONG LASTING
German endocrinologists have reported that " a novel, long-acting
testosterone formulation (testosterone undecanoate) ... requires one
intramuscular injection every 3 months. Researchers found it to be
well tolerated, producing stable levels of testosterone. This
formulation is manufactured in Germany and available in the UK under
the name Nebido.
How is it done: Three or four cylindrical pellets are inserted in the
wall of the abdomen or thigh under local anaesthetic.
How often: Every six months
Advantages: Six-month period between procedures
Disadvantages: There may be a local infection in the site where the
pellets are inserted.
Testosterone levels are at peak after 2-4 weeks, then
Pellets may be extruded (pushed out) by the body and
would have to be reinserted.
Medical Research Council Human Reproductive Sciences Unit, University
of Edinburgh, Edinburgh, United Kingdom EH16 4SB.
How it is done: testosterone taken in pill form
How often: 3 or 4 times per day
Advantages: Some liver toxicity
Disadvantages: There can be somewhat erratic absorption of the drug,
although this is minimized it if is taken with food. Also, it is only
useful for low levels of replacement.
www.princetoncme.com/pdf/programs/2006-167.pdf (page 4)
TRANSDERMAL (through the skin)
How it is done: patches are applied to the back, abdomen or thigh (usually 2)
How often: Patches are changed daily.
Advantages: Fairly constant delivery of testosterone throughout the
day; no peaks and valleys
Disadvantages: Some extent of skin irritation has been reported 67%
of users (http://www.princetoncme.com/pdf/programs/2006-167.pdf ); the
patch may make a rustling sound; it can fall off, especially from
How it is done: a testosterone tablet sticks to the gum, just above
one of the upper teeth,
How often: Every 12 hours
Advantages: Steady delivery of testosterone throughout the day through
the inner lining of the lips; minimal liver toxicity
Disadvantages: Can cause local irritation; can be dislodged
How it is done: A gel is self-applied to the shoulders, back, or chest
How often: Daily
Advantages: Stable blood levels throughout the day; safe
Disadvantages: Skin irritation (rare); gel can come off through
From the National Health Service, UK:
"Whichever type of testosterone replacement therapy you take, you will
need to have blood taken a few weeks after you begin, to measure your
levels of testosterone in order to check that you are getting the
right amount of hormone. You will also need blood tests at regular
intervals to check testosterone levels and ensure you do not develop
rare but potentially serious side effects of treatment such as
thickening of your blood or abnormal liver function.
Hypogonadism and Testosterone Replacement Therapy
Digital Urology Journal Testosterone Replacement Therapy
The Pituitary Foundation Testosterone Replacement Therapy
PAMPHLET: Testosterone Implant
GOOGLE SEARCH STRATEGY
Search terms: "testosterone replacement therapy" pituitary
Search terms: hypogonadism testosterone site:.uk
Search terms: testosterone replacement site:.uk
Also: US National Library of Medicine
(searched for research papers on testosterone replacement males,
humans, ages: 15-44, last two years)
I hope this will satisfy your desire to know what you are getting
into. Only you and your doctor can decide on what's right for you.
All the best,