Testosterone is often discussed in the context of sexual function and male characteristics, but it also supports muscle mass, bone strength, and other systems involved in overall health. Research summaries have reported that low testosterone in men is associated with higher rates of negative outcomes, including all-cause mortality and, at very low levels, cardiovascular disease (CVD) mortality. These findings describe an association, not proof of causation, and they do not establish a direct cause-and-effect relationship.
What a large evidence review examined
A systematic review and meta-analysis published in Annals of Internal Medicine reviewed evidence on how baseline serum testosterone levels relate to long-term outcomes. In a pooled analysis led by researchers from The University of Western Australia, with collaborators across Australia, Europe, and North America, data from 11 studies involving roughly 24,000 participants were assessed to explore how testosterone levels in older men track with mortality risk.
In the included cohorts, total testosterone was measured using mass spectrometry, and participants were followed for at least five years. Researchers also evaluated related hormone markers, including sex hormone–binding globulin (SHBG), luteinizing hormone (LH), dihydrotestosterone (DHT), and estradiol, to better understand how these measures aligned with outcomes.
Key findings, stated carefully
The analysis examined relationships between baseline hormone levels and the relative risk of cardiovascular events, cardiovascular deaths, and deaths from any cause.
Men with low total testosterone below 7.4 nmol/L (213 ng/dL) showed a higher likelihood of death from any cause, also called all-cause mortality.
Men with very low testosterone below 5.3 nmol/L (153 ng/dL) showed a higher risk of death from cardiovascular disease, also called CVD mortality.
These thresholds are research definitions used in pooled analyses and may not match individual laboratory reference ranges or determine an individual diagnosis. The evidence also does not prove that low testosterone directly causes cardiovascular deaths or mortality. Observational associations cannot determine causation.
Why association matters
Experts often emphasize that it remains unclear whether testosterone is a direct driver of risk or a biological indicator of overall health status. One proposed explanation is that lower testosterone is frequently linked with changes in body composition, such as lower lean muscle mass and greater fat accumulation, which are also connected to cardiometabolic risk. Low testosterone may also appear alongside other coexisting medical issues that influence cardiovascular health outcomes, which can contribute to the associations observed in population studies.
Health concerns commonly discussed alongside low testosterone
Clinical discussions often include sexual health changes such as reduced libido and possible erectile difficulties, along with more general concerns like fatigue or low energy, mood changes, and changes in muscle and bone density over time. Low testosterone is sometimes discussed in relation to serious cardiovascular outcomes, but these references typically reflect population-level associations that can overlap with other underlying health issues rather than a guaranteed cause-and-effect pathway.
How testosterone is typically evaluated in lab work
Determining whether testosterone is low generally starts with a blood test, but interpretation often goes beyond one number. Testosterone values can fluctuate, and lab reports commonly include both total testosterone and free testosterone.
Total testosterone includes protein-bound and unbound hormone.
Free testosterone is often described as the more bioavailable fraction.
Because total and free testosterone can differ, clinicians typically interpret results in context, considering symptoms, repeat testing when appropriate, and other relevant markers, including SHBG and related hormones when needed.
What people commonly discuss with a licensed clinician
Conversations about low testosterone commonly include lab interpretation, symptom patterns, overall cardiometabolic health, and potential medical approaches. In some settings, testosterone replacement therapy (TRT) may be discussed as one possible prescribed option depending on diagnosis and individual risk factors. This mention of TRT is informational only and is not a claim that TRT prevents cardiovascular disease, reduces mortality risk, or produces guaranteed outcomes.
Medical and Compliance Note (for responsible publication)
This article is intended for general educational purposes only. It is not medical advice, does not establish a diagnosis, and does not guarantee outcomes. It does not diagnose, treat, cure, or prevent any disease. This content is not intended to promote any prescription drug.
Research findings summarized here reflect population-level associations and must be interpreted alongside individual health history and clinician evaluation. Laboratory reference ranges and clinical decisions can vary. If you think you may be experiencing a medical emergency, seek immediate medical care.
FAQ
What does low testosterone in men mean in research studies
In many studies, low testosterone in men refers to total testosterone below a defined threshold used for analysis. Some pooled analyses use cutoffs such as 7.4 nmol/L (213 ng/dL) for low and 5.3 nmol/L (153 ng/dL) for very low, but these are research definitions and may differ from individual lab reference ranges.
Does low testosterone cause cardiovascular disease or death
The evidence summarized here shows an association between low testosterone and outcomes like all-cause mortality and CVD mortality. It does not prove that low testosterone directly causes these outcomes.
Why might low testosterone be linked with higher CVD risk
Researchers often discuss that low testosterone can coincide with factors like higher body fat, lower lean muscle mass, and other cardiometabolic conditions. These overlapping patterns may help explain the associations observed in population studies.
What is the difference between total testosterone and free testosterone
Total testosterone includes both protein-bound hormone and unbound hormone. Free testosterone refers to the fraction often described as more bioavailable and more readily usable by the body. Differences between the two can occur depending on factors such as SHBG.
How is low testosterone typically checked
It is usually assessed with a blood test. Because testosterone levels can fluctuate, clinicians may consider timing, repeat testing, symptoms, and additional markers such as SHBG, LH, or others depending on the situation.
What is testosterone replacement therapy TRT
Testosterone replacement therapy (TRT) is a prescribed medical approach that may be discussed when testosterone is clinically low and symptoms are present. TRT can be available in different formats depending on clinical evaluation and local medical standards.
