Testosterone and its effects on sexual function
1. A
long–term prospective study of the physiologic and behavioral effects of hormone replacement in untreated hypogonadal men – A.S. Burris et al. Journal of Andrology
1992; 13(4):297–304.
Men
with low levels of testosterone
who
had not yet been treated with supplemental hormone showed significantly higher
levels of depression, anger, fatigue and confusion than did
men with acceptable testosterone levels. During testosterone replacement therapy, scores
improved. Also during treatment, these men reported increased sexual interest
and greater numbers of spontaneous erections. (Design of Study: Hypogonadal men before and during
testosterone treatment compared to untreated normal
men and untreated
infertile men; no placebo treated controls.)
Journal of Clinical Endocrinology
and Metabolism 1979; 48(6):955–958.
The study found
that the effect of testosterone
replacement on
sexual activity in
hypogonadal men is rapid, reliable, and not due
to placebo effect.
To maintain testosterone
levels and adequate sexual
function, testosterone replacement should be administered
on an ongoing basis. (Design of Study:
Hypogonadal
men during double blind, randomized,
cross-over treatment with sub-replacement and replacement doses of testosterone; no placebo
treated controls.)
3. Improvement of sexual
function in testosterone deficient men treated for one year
with a permeation enhanced
testosterone transdermal
system – S. Arver et al. Journal of Urology,
1996; 155(5): 1604-1608.
This
study observed that nocturnal erections occurred more
frequently with longer duration and
greater rigidity, and patient assessments of sexual desire and
weekly number of erections were higher in hypogonadal men
when testosterone levels were normalized, as compared with measurements occurring
during testosterone withdrawal. (Design of
Study:
Hypogonadal men during open-label
testosterone treatment; not a controlled study.)
4. Androgen Replacement:
Sexual Behavior, Affect and Cognition – A.W. Meikle, editor.
Hormone Replacement, Contemporary
Endocrinology. Humana Press, Totowa, NJ
(in press).
This
chapter reviews studies that evaluate the
effects of testosterone replacement
on erectile function in
hypogonadal males. (A review article; not a controlled study.)
Testosterone and its effects on mood and thinking
1. A
long–term prospective study of the physiologic and behavioral effects of hormone replacement in untreated hypogonadal men – A.S. Burris et al. Journal of Andrology
1992; 13(4):297–304.
Men
with low levels of testosterone
who
had not yet been treated with supplemental hormone showed significantly higher
levels of depression, anger, fatigue, and confusion than did
men with acceptable testosterone levels. During testosterone replacement
therapy, scores for the
previously untreated
hypogonadal men improved indicative of less
depression, anger, fatigue, and confusion.
(Design
of Study: Hypogonadal men before and during
testosterone treatment compared to untreated normal
men and untreated
infertile men; no placebo treated controls.)
2. Androgen–behavior correlations in
hypogonadal men and eugonadal men. II.
Cognitive abilities – G.M. Alexander et al. Hormones and
Behavior 1998; 33(2):85–
94.
Reasoning abilities
were assessed in 33 men
with low levels of testosterone
who
were receiving supplemental testosterone, 10 men with normal levels of
testosterone
men with
normal testosterone levels who
did not receive supplemental testosterone. Prior to and after being given testosterone the men
completed tests that measured visual–spatial ability, verbal fluency,
perceptual speed, and verbal memory. Men
with low testosterone seemed
to have lower levels of verbal fluency;
these improved following treatment with
testosterone. These data suggest that testosterone may play some role
in influencing some aspects
of reasoning and thinking.
(Design
of Study: Hypogonadal men before and during testosterone
replacement treatment compared to normal men before and during
high dose testosterone and untreated
normal
men; no placebo-treated controls.)
3. Testosterone
replacement therapy improves mood in hypogonadal men – a clinical research center study – C. Wang et al.
Journal of Clinical Endocrinology and Metabolism 1996; 81(10):3578–3583.
The study
evaluated changes in mood for
60 days in 51 hypogonadal men. Researchers found
that testosterone replacement therapy
in
hypogonadal men improved their positive mood parameters including energy, well/good feelings, and friendliness.
Testosterone replacement also
decreased negative mood parameters including anger, nervousness, and irritability.
(Design of Study:
Hypogonadal
men before and during testosterone
treatment with a variety of testosterone formulations; not a controlled study.)
Testosterone and its effects on body composition and bone density
1. Effects
of testosterone replacement on muscle mass and muscle
protein synthesis in hypogonadal
men: a clinical research center study
– I.G. Brodsky et al. Journal of Clinical
Endocrinology and Metabolism 1996;
81(10):3469–3475.
Researchers measured body composition and muscle protein synthesis in five men with low testosterone before and six months
after beginning testosterone replacement therapy. After
testosterone therapy, all five men showed an increase in fat–free mass,
a decrease in fat mass and
an increase in muscle
mass (65 percent of the
increase in fat–free mass could be attributed to increased muscle
mass). The scientists also found that the increased muscle mass was caused by the ability of testosterone
to stimulate muscle protein synthesis. (Design of Study:
Hypogonadal
men before and during testosterone
treatment; not a controlled study.)
2. Transdermal
testosterone gel improves
sexual function, mood, muscle strength, and
body composition parameters in hypogonadal
men – C. Wang et al. Journal of Clinical Endocrinology and Metabolism 2000;
85(8): 2839-2853.
This study
evaluated the effects of 180 days of treatment with testosterone patch and
testosterone gel on sexual function, muscle
strength, lean body, and fat mass in
227 hypogonadal
men aged 19-68. The study
found that sexual function and
mood improved in all treatment groups; mean muscle strength in the leg
press increased in all treatment groups;
lean body mass
increased greater
in the highest dose of testosterone gel
compared
to lower dose gel and
patch. An increase in lean body mass and reduction in fat mass were
correlated with the mean testosterone levels after treatment. (Design of Study:
Hypogonadal
men
before and during testosterone treatment with either testosterone gel or testosterone
patch; no placebo treated controls.)
3. Effects of transdermal
testosterone gel on bone turnover markers
and bone mineral density in hypogonadal
men – C. Wang et al. Clinical
Endocrinology 2001; 54(6):
739-750.
This study found
that transdermal testosterone gel
application in doses of
5-10
grams/day
(delivering 50-100
mg of testosterone)
for 6 months decreased bone
resorption
markers and increased bone formation activity
markers (transiently)
in 227 men aged 19-68 years. The highest
dose gel resulted in increased bone
mineral
density in the
spine and hip only
in
the higher treatment group.
At
the time of the articles the authors indicated that longer term data would determine if the positive effects on bone would persist.
The same authors reported at the
2002 Endocrine Meetings that positive effects on bone continued to increase with continued treatment up to 42 months. (Design
of
Study: Hypogonadal men
before and during testosterone
treatment with either
testosterone gel or testosterone patch;
no placebo treated controls.)
4. Increase
in bone density and lean body mass during testosterone administration in
men with acquired hypogonadism
– L. Katznelson et al. Journal
of Clinical Endocrinology and Metabolism 1996; 81(12):4358–4365.
Scientists
assessed the muscle and bone effects of
testosterone replacement therapy in 29
men
aged 22 to 69 with low blood
levels of the hormone. The
men
were evaluated at six–month
intervals for 18 months. The
researchers found that body fat and subcutaneous fat significantly decreased while lean muscle mass and bone density significantly increased.
The scientists concluded that the beneficial
effects of testosterone administration on
body
composition and bone density may provide additional
indications for testosterone therapy in such men.
(Design of Study: Randomized, placebo controlled
study of older hypogonadal men
before
and during testosterone injections compared
to before and during placebo
injections.)
5. Testosterone
replacement in older hypogonadal men: a 12–month randomized controlled
trial
– R. Sih et al. Journal of Clinical Endocrinology and Metabolism 1997;
82(6):1661–1667.
Researchers examined the year–long
effects of testosterone replacement therapy
in
32 men in their 60s (15 men
received a placebo and 17 received biweekly injections of testosterone). They found that the men who
received testosterone
showed improved grip strength
in both hands and increased
levels of hemoglobin, the blood component that carries
oxygen. The investigators concluded that testosterone may have a role
in treating frailty in older
men. (Design of Study: Hypogonadal men before and
during testosterone treatment; no placebo treated
controls.)
6. Long–term
effect of testosterone therapy
on bone mineral density in hypogonadal men – H.M. Behre et al. Journal of
Clinical Endocrinology and Metabolism 1997;
82(8):2386–2390.
The researchers studied bone mineral density in 72
men
who received testosterone
replacement therapy for up to 16
years. Bone mineral density was
measured annually. The most significant increase
in bone mineral density was seen during the first year of testosterone replacement
therapy. Long–term treatment maintained bone
mineral density
at levels consistent for age in all men. (Design of Study: Randomized,
placebo controlled study of older
hypogonadal men treated with testosterone patches or placebo patches.)
7. Effect of
testosterone treatment
on bone mineral density in men over
65 years of age – P.J.
Snyder, et al. Journal of Clinical
Endocrinology and Metabolism
1999;84:1966–1972.
Researchers examined changes in bone mineral
density in 108 men over 65 years of age who received
testosterone for 36 months. The
study found that increasing testosterone to the midnormal range for young men
did not increase lumbar spine
bone density overall, but did increase it in those men with low
pretreatment testosterone
levels. (Design of Study: Randomized,
placebo controlled study of older
hypogonadal men treated with testosterone
patches and placebo patches.)
8. Effect of
testosterone treatment on body composition and muscle strength in men over 65 years of age – P.J. Snyder, et al. Journal of Clinical Endocrinology
and Metabolism 1999;84:2647–2653.
Researchers examined changes in body composition
and muscle strength in
108 men over 65 years of
age who received testosterone
for 36 months. The
study found that increasing testosterone concentrations
in men over 65 years of age to the midnormal range decreased fat mass and increased
lean mass, but did
not necessarily increase muscle
strength. (Design of Study: Randomized, placebo
controlled study of men
over age 65 treated with testosterone
patches and placebo patches.)
Testosterone and its effects on HIV positive men with low testosterone
1. Testosterone
replacement in HIV
illness – J.G. Rabkin et
al.
Archives of General
Psychiatry 2000; 57(2):141-147.
A total of 70 HIV–positive men with low testosterone
levels
completed a six-week trial
of biweekly testosterone or placebo treatments. Seventy four
percent of men who received
testosterone reported much or
very much improved libido, compared to 19% of placebo-treated men. Of men with fatigue at baseline,
59% of
testosterone-treated men had improved energy,
compared to
25% of placebo-treated men. Of
men with Axis 1
depression at baseline, 58% of men
who received testosterone versus 14% of men treated with placebo
reported improved mood. Testosterone improved muscle
mass by 1.6 kg over 12 weeks in the entire group of men treated with testosterone,
and 2.2 kg in those
with wasting at baseline.
(Design
of
Study: HIV-positive men
with
low testosterone levels before and during
testosterone treatment; no placebo
treated controls.)
2. Effects of androgen
administration in men with
the AIDS wasting syndrome. A randomized, double–blind,
placebo–controlled trial – S. Grinspoon et al. Annals
of Internal Medicine 1998; 129(1):18–26.
Fifty–one HIV–positive men with
a mean age of 42 who
had wasting and low
testosterone were randomly assigned
to receive testosterone or placebo
every three weeks for six months. Testosterone–treated men gained fat–free mass, lean body mass and muscle mass. These men also reported
they felt better, had an improved quality of life and improved appearance. (Design of Study: Double-blind, randomized, placebo-controlled trial of testosterone versus placebo
therapy in HIV-infected men with AIDS
wasting syndrome.)
3. Testosterone supplementation therapy for
older men: Potential
benefits and risks –
D.A. Gruenewalk and A.M. Matsumoto. Journal of the American Geriatric
Society
2003; 51(1):101-115.
This study of men age 60 years evaluated one or
more physical, cognitive, affective, functional, or
quality-of-life outcomes. In general, these
studies found increased
lean body mass and decreased fat mass. Upper and lower body strength, functional performance, sexual functioning, and
mood were improved or unchanged with testosterone treatment. Testosterone improved
exercise-induced
coronary
ischemia in men with coronary
heart disease, but angina was improved or unchanged. Compared to men with less marked testosterone deficiency, men with low testosterone levels were more
likely
to demonstrate improvements in bone
mineral density, self-perceived functional
status, libido and sexual function, and
exercise-induced ischemia. No major unfavorable effects on lipids
were reported, but hematocrit and prostate specific
antigen often increased. (Qualitative review of placebo-controlled trials.)
Source: The Hormone Foundation
