Four Testosterone Claims You Have Read Twenty Times. Here Is What Each One Rests On.

Start with the number at the top of every thread you have ever read.

Testosterone down 40 to 60% in fifty years.

Nobody attaches a source to it, because the real study says something smaller and more useful.

Thomas Travison and colleagues published it in the Journal of Clinical Endocrinology and Metabolism in 2007.
https://doi.org/10.1210/jc.2006-1375

They followed men aged 45 to 79 in the Boston area across three waves: 1,374 men in 1987 to 1989, 906 in 1995 to 1997, and 489 in 2002 to 2004.

Testosterone fell around 1.2% a year. Roughly 17% across the whole period.

The drop held after they adjusted for weight, smoking, illness and medication.

Then a separate analysis of US national NHANES data covering 1988 to 2004 found no decline in the overall population.
https://pmc.ncbi.nlm.nih.gov/articles/PMC4137971/

A real trend, in one city, of 17%. The thread rounded it up threefold.

Four questions catch this, and they take ninety seconds.

Ask them of any claim before you act on it.

What species? Rats and mice run through most of this literature. A number from a rodent tells you nothing about your Tuesday.

How many, and for how long? Ten men for two weeks sits a long way from a thousand men for a decade.

What did they actually measure? Blood, saliva, a questionnaire and a sperm sample answer different questions.

Where did it appear? A conference abstract skips the review a journal paper goes through.

Now use them on the claim you have seen most.

Pomegranate raises testosterone 24%. The source is a 2012 conference abstract by Emad Al-Dujaili and Nacer Smail.
https://www.endocrine-abstracts.org/ea/0028/ea0028p313

Sixty volunteers. Twenty-two of them men, thirty-eight women. Mean age 39.1. Two weeks of juice, saliva sampled three times a day.

Run the four questions. Human, yes. Sixty people over two weeks, small and short. Saliva rather than blood. A conference abstract rather than a reviewed paper.

Drink the juice if you like it. Nothing there tells you it fixed anything.

Do this before you buy the next thing you read about.

the 300% claim, the supplement with nothing behind it, and what the sequence looks like once you stop shopping.