Condition: Testosterontherapie

The TRAVERSE trial randomized 5,246 men aged 45 to 80 with hypogonadism and either existing or high risk of cardiovascular disease to testosterone gel or placebo. A primary cardiac event occurred in 7.0% on testosterone and 7.3% on placebo (hazard ratio 0.96, 95% CI 0.78 to 1.17), meeting the pre-set non-inferiority margin over a mean follow-up of about three years. Measured in: 5,246 men aged 45 to 80 with symptomatic hypogonadism and pre-existing or high risk of cardiovascular disease.. Non-inferiority is a ceiling on added risk, not a benefit, and the same trial found more atrial fibrillation, acute kidney injury and pulmonary embolism on testosterone, so the reassurance about major cardiac events sits alongside these specific signals.

In a coronary-imaging substudy of the Testosterone Trials, 138 men aged 65 and older completed CT angiography before and after one year of treatment. Testosterone was associated with a significantly greater increase in noncalcified coronary plaque volume than placebo (estimated difference 41 mm3, 95% CI 14 to 67; P=0.003) and in total plaque volume (difference 47 mm3, 95% CI 13 to 80). Measured in: 138 men aged 65 and older with an average of two testosterone readings under 275 ng/dL who completed coronary CT angiography at baseline and one year.. This is a surrogate imaging outcome in a small group over one year, and it was not accompanied by more cardiac events in this study or in the much larger TRAVERSE trial, so its clinical meaning is unsettled.

In the Sexual Function Trial of the Testosterone Trials, 470 men aged 65 or older with low libido and an average testosterone below 275 ng/dL were randomized to testosterone gel or placebo for one year. Testosterone significantly improved 10 of 12 measures of sexual activity, along with sexual desire and erectile function, and the size of the improvement tracked the rise in testosterone and estradiol, not crossing any single threshold. Measured in: 470 men aged 65 and older with low libido, average testosterone under 275 ng/dL, and a partner willing to have intercourse at least twice a month.. The gains were clearest for desire and overall sexual activity and weaker for erectile function specifically, and the trial ran for one year in men with confirmed low levels, so it does not speak to men whose testosterone is normal.

A systematic review and meta-analysis of randomized, placebo-controlled trials found that in hypogonadal men testosterone replacement therapy improved sexual desire, erectile function and sexual satisfaction compared with placebo, while also increasing the risk of erythrocytosis, a thickening of the blood. Measured in: Hypogonadal men enrolled in randomized, placebo-controlled trials of testosterone replacement therapy, pooled across studies.. The improvements are modest averages and the constituent trials were mostly short, so the meta-analysis measures symptom change over months, not years and cannot settle long-term benefit or harm.

In the Testosterone Trials, raising testosterone to the mid-normal range for one year in symptomatic men aged 65 and older gave no significant benefit for vitality on the FACIT-Fatigue scale, and did not increase the share of men walking at least 164 feet (50 meters) further in six minutes within the Physical Function Trial's own population. Sexual function improved and mood improved slightly. Measured in: 790 men aged 65 and older with an average of two testosterone readings under 275 ng/dL and symptoms of low testosterone, across the seven coordinated Testosterone Trials.. A pooled analysis across all three arms did show a small edge in the six-minute walk, so the null is for the trial's primary physical-function population, not every possible reading of the data, and the study lasted one year.

A random-effects meta-analysis of 27 randomized placebo-controlled trials in 1,890 men found that testosterone treatment was associated with a small but significant reduction in depressive symptoms compared with placebo (Hedges g 0.21, 95% CI 0.10 to 0.32), with larger effects at higher doses and in more carefully selected samples. Measured in: 1,890 men across 27 randomized placebo-controlled trials, spanning hypogonadal and eugonadal men reporting depressive symptoms on validated scales.. The effect is small and the trials were heterogeneous, few examined depression as their main outcome, and the benefit was most reliable at higher doses, so this is a signal in symptom scores, not an established treatment for depression.

In the Cognitive Function Trial of the Testosterone Trials, 493 men aged 65 and older with low testosterone and age-associated memory impairment showed no significant change in delayed paragraph recall after one year of testosterone versus placebo (adjusted difference -0.07, 95% CI -0.92 to 0.79), and no benefit for visual memory, executive function or spatial ability. Measured in: 493 men aged 65 and older with low testosterone and age-associated memory impairment, randomized to testosterone gel or placebo for one year.. The trial ran for one year in men who already had memory complaints, so it does not address whether very long-term treatment or other populations would differ, but within its design the null was consistent across every cognitive measure.

In the Bone Trial of the Testosterone Trials, 211 men aged 65 and older with low testosterone had a significantly greater rise in spine trabecular volumetric bone density on testosterone than placebo over one year (7.5% vs 0.8%; treatment effect 6.8%, 95% CI 4.8 to 8.7), with estimated spine bone strength rising 10.8% versus 2.4%, and gains also seen at the hip. Measured in: 211 men aged 65 and older with an average of two testosterone readings under 275 ng/dL, randomized to testosterone gel or placebo for one year.. The trial measured bone density and calculated strength, not fractures, so whether the density gain would translate into fewer broken bones was left for a larger, longer study to answer.

Giving testosterone from outside shuts down the pituitary signals (LH and FSH) that drive the testes, which collapses the testosterone concentration inside the testis needed for sperm production. The result is a sharp fall in sperm count, often to zero, which is why exogenous testosterone is described as a preventable cause of male infertility and is not given to men trying to conceive. Measured in: Men receiving exogenous testosterone, reviewed across the andrology and male-fertility literature.. Suppression is usually reversible after stopping, but recovery can take months to more than a year and is not guaranteed in every man, so it cannot be treated as risk-free for someone who wants children.

The Endocrine Society clinical practice guideline recommends diagnosing hypogonadism only in men who have both symptoms of testosterone deficiency and unequivocally low morning fasting total testosterone, confirmed on at least two separate mornings, since levels are highest in the morning and fall with acute illness. It recommends against starting testosterone in men planning fertility in the near term. Measured in: Adult men, as addressed by an Endocrine Society clinical practice guideline synthesizing the evidence and expert consensus.. This is a guideline recommendation reflecting expert consensus and graded evidence, not a single trial, and testosterone assays and reference ranges vary between laboratories, which is part of why repeat morning testing matters.

A meta-analysis of 24 studies found that losing weight raised total testosterone in men, with a low-calorie diet increasing it by about 2.9 nmol/L and bariatric surgery by about 8.7 nmol/L, both significant against baseline. The rise was larger in men who lost more weight and in younger, more obese, non-diabetic men, pointing to weight itself as a driver of the low levels. Measured in: Men in 24 studies of diet-based weight loss or bariatric surgery, with testosterone measured before and after weight loss.. Most of the diet studies were uncontrolled before-and-after comparisons, not randomized trials, so the effect is well replicated but the magnitude for any individual depends heavily on how much weight is lost.

A meta-analysis of 29 randomized controlled trials in 1,083 middle-aged and older men (mean age 64.5, mean testosterone 10.9 nmol/L) found that testosterone treatment reduced total body fat by 1.6 kg (95% CI -2.5 to -0.6), about a 6.2% fall from baseline fat, and increased fat-free (lean) mass by 1.6 kg (95% CI 0.6 to 2.6), about a 2.7% rise, with no change in overall body weight. The effect on muscle strength was heterogeneous, with only a tendency toward improvement at leg extension and dominant-hand grip. Measured in: 1,083 middle-aged and older men across 29 randomized controlled trials, mean age 64.5 years and mean baseline testosterone 10.9 nmol/L, randomized to testosterone or placebo.. The body-composition change is consistent across trials, but it is a shift in the muscle-to-fat ratio, not weight loss, and it was not matched by a clear gain in strength, so it should not be read as a functional or fitness benefit on its own.

In a controlled sleep study, 10 healthy young men were restricted to five hours of sleep a night for one week after a baseline of full sleep. Their daytime testosterone fell by 10 to 15%, with the lowest levels in the afternoon and evening, showing that curtailed sleep suppresses testosterone within days. Measured in: 10 healthy young men studied under laboratory sleep restriction of five hours per night for one week.. This was a small, short study in young healthy men, not in older men or those with low levels, so it demonstrates that sleep loss lowers testosterone without quantifying the effect across the men most likely to be considering treatment.