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Updated: Jun 5, 2026

Combining Behavioral Endocrinology and Experimental Economics: Testosterone and Social Decision Making
Published on: March 2, 2011
Why do we need a trial on the effects of testosterone therapy in older men?
1Division of Cardiovascular Sciences, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA.
Abstract:
Decreases in levels of sex hormones occur with aging. Observational studies have found associations of low testosterone concentrations in older men with adverse symptoms; however, these associations do not prove causality. Therefore, the question arises whether to treat older men whose serum testosterone is low. In 2009, the Testosterone Trial (T Trial) was funded to examine the efficacy of therapy in 800 elderly men with low testosterone levels; potentially associated symptoms; and abnormalities in physical, sexual, or cognitive function or vitality.
Insights
Low testosterone in older men may cause adverse symptoms, but causality remains unclear. The Testosterone Trial investigated whether testosterone therapy improves physical, sexual, and cognitive function in elderly men with low levels.
Area of Science:
- Endocrinology
- Geriatrics
- Men's Health
Background:
- Sex hormone levels, particularly testosterone, decline with aging in men.
- Observational studies suggest links between low testosterone and adverse symptoms in older men, but causality is not established.
- Clinical decisions regarding testosterone replacement therapy in aging men with low levels require evidence of efficacy.
Purpose of the Study:
- To investigate the efficacy of testosterone therapy in elderly men with documented low testosterone levels.
- To assess the impact of testosterone therapy on physical function, sexual function, cognitive function, and vitality.
- To address the clinical question of whether to treat older men with low serum testosterone.
Main Methods:
- The Testosterone Trial (T Trial) was initiated in 2009.
- The study enrolled 800 elderly men with low testosterone levels.
- Participants were assessed for potential benefits of testosterone therapy on various health parameters.
Main Results:
- The study aimed to determine if testosterone therapy offers significant benefits.
- Results were intended to clarify the causal relationship between testosterone levels and age-related symptoms.
- The trial focused on objective measures of physical, sexual, cognitive, and vitality outcomes.
Conclusions:
- The Testosterone Trial provides crucial data on the efficacy of testosterone therapy in older men.
- Findings will inform clinical practice regarding testosterone supplementation for age-related hypogonadism.
- Evidence from the T Trial is essential for guiding treatment decisions in this demographic.
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