Gianluca
Well-Known Member
I was using AI for some research, it made an interesting quick summary of Testosterone. I thought I would share.
Pre-1935 – Theories of male virility
- Ancient and early medical theories linked testes with masculinity.
- Castration known to affect physical and behavioral traits.
- No chemical identification of testosterone.
1935 – Discovery and synthesis of testosterone
- Ernst Laqueur isolates testosterone from bull testes.
- Butenandt & Ruzicka synthesize testosterone from cholesterol (Nobel Prize in 1939).
- Marks the birth of endocrinology of androgens.
1940s–1950s – Early crude measurements
- Used urinary 17-ketosteroids as a proxy for testosterone.
- Very inaccurate and nonspecific.
- No direct measurement of serum testosterone.
1960s – Reliable measurement begins
- Introduction of radioimmunoassay (RIA) by Rosalyn Yalow (Nobel Prize 1977).
- First time blood testosterone could be measured reliably.
1967 – Southren et al. study
- Used radioactive testosterone tracers and metabolic clearance rate.
- Found 6–7 mg/day production in young healthy males.
- Becomes the standard estimate for physiological production.
1980s–1990s – Improved techniques
- Better RIA kits and hormonal assays.
- Studies begin examining:
- Diurnal rhythm (peak in morning)
- Age-related decline
- Effects of obesity, illness, etc.
- Diurnal rhythm (peak in morning)
- Age-related decline
- Effects of obesity, illness, etc.
2000s–2010s – Mass spectrometry (LC-MS/MS)
- Gold standard for measuring serum testosterone accurately.
- Shows:
- Free vs. total testosterone differences
- Better population-level data
- Confirms ~4–7 mg/day production in young men
- Free vs. total testosterone differences
- Better population-level data
- Confirms ~4–7 mg/day production in young men
2017 – Alarming sperm/testosterone trends
- Meta-analyses show sperm count and testosterone levels have declined >50% since the 1970s.
- Raises concerns about environmental estrogens, stress, lifestyle, and diet.
2020s–present – Personalized hormone mapping
- Growing use of saliva, urine, and 24-hour profiles
- Recognition of wide interindividual variation
- Integration into TRT protocols, anti-aging, and performance medicine
Summary:
Year Milestone 1935 Testosterone isolated & synthesized 1940s Urinary hormone estimates (crude) 1960s RIA enables serum T measurements 1967 First accurate estimate: 6–7 mg/day 2000s LC-MS/MS becomes gold standard 2017 Declining population T levels documented
| Year | Milestone |
|---|---|
| 1935 | Testosterone isolated & synthesized |
| 1940s | Urinary hormone estimates (crude) |
| 1960s | RIA enables serum T measurements |
| 1967 | First accurate estimate: 6–7 mg/day |
| 2000s | LC-MS/MS becomes gold standard |
| 2017 | Declining population T levels documented |
