The Claim

Average testosterone levels in men declined by 54% between 1972 and 2019, corresponding to an average annual decline of more than 1%.

What the research says

Roughly balanced

Support and challenge are close. The picture may shift as more studies come in.

Supports
43score
Challenges
47score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Quantitative
3 studies reviewed
In plain English

Between 1972 and 2019, the average testosterone level in men dropped by 54%, which equals more than a 1% decrease each year.

See the scientific wording

Average testosterone levels in men have declined by 54% over a 47-year period (1972–2019), representing an average annual decline of more than 1%.

Why this might work

As men get older and gain body fat, their fat tissue grows larger and sends signals that reduce testosterone production in the testes. At the same time, the brain's control center for testosterone stops signaling the testes as strongly. This causes testosterone levels to drop steadily over time.

Supported mechanismbased on 3 studies

What the research says

3 studies

  1. Study: EFFECT OF AGING AND OBESITY RELATED TESTOSTERONE DECLINE ON SERUM ADIPONECTIN LEVELS OF HEALTHY MALES

    The study found that older, overweight men have 54% less testosterone than younger, lean men — which matches the 54% drop claimed over decades. This suggests testosterone naturally falls as men age, supporting the idea that average levels have dropped over time.

  2. Study: RETHINKING LOW TESTOSTERONE IN OLDER MEN: ASSOCIATION WITH OBESITY RATHER THAN AGING.

    This study found that older men today don’t have lower testosterone than younger men — it’s about how much belly fat they have, not how old they are. So it doesn’t support the idea that testosterone has been dropping steadily for decades.

  3. Study: Age-related changes in serum reproductive hormone levels and prevalence of androgen deficiency in Chinese community-dwelling middle-aged and aging men

    The study looked at how testosterone changes as men get older, not how testosterone levels changed in all men from 1972 to 2019. It found only small yearly drops in active testosterone, not the huge 54% drop claimed.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 3 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.