Men's testosterone levels have dropped by more than half in the last 50 years. So a typical man today has much less of this hormone than his grandfather did at the same age.
See the scientific wording
The average serum testosterone concentration in adult men has decreased by 54% over the last five decades.
Correlational — new studies may shift this
Observational2 moderate-quality studies link this claim to the outcome, but causation is not established.
What the research says
2 studies reviewedSupporting (2)
Secular trends in testosterone- findings from a large state-mandate care provider
Cross-Sectional StudyHuman2020
The study shows that men's testosterone levels have been going down over the past few years, which agrees with the claim that they've dropped a lot in the last 50 years, but it doesn't directly measure the full 54%.
Systematic Review With Meta-AnalysisMeta-analysis
Scientists found that men's testosterone levels have been going down over the past 50 years, which matches the claim that they have declined.
Contradicting (0)
No contradicting studies found yet
That doesn't mean it's settled — it just means no study has tested the opposite.
Quality-weighted scoring: we follow the GRADE framework — each study is rated High, Moderate, Low, or Very Low based on study design, methodology rigor, and risk of bias. A single high-quality RCT can outweigh several weaker observational studies.
Scores reflect study quality, not just count.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 2 supporting studies
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