Global decline
Travison et al. showed that a 60-year-old man in 2004 had substantially lower testosterone than a 60-year-old in 1987. The decline is not explained by ageing — it is population-wide, and it continues.
Every chart is shown in both the Danish/EU unit (left axis) and the US unit (right axis). Hover any reference point for a fact box with the range, both units, and how it compares historically. A dashed horizontal guide is drawn at that level and marks exactly where the other curves cross it.
Chart 01
Left axis nmol/L (DK/EU), right axis ng/dL (US). The shaded band is the 1970s/80s top 10% range; today's average man spends his entire adult life beneath the floor of that band.
Chart 02
Left axis pmol/L (DK/EU), right axis pg/mL (US). Free testosterone is what reaches the receptor. It falls faster than total testosterone because SHBG rises with age.
Chart 03
EMAS-style modelling. Indexed function (100 = full capacity) plotted against free testosterone. Decline is not linear — it collapses below roughly 350 pmol/L (≈ 101 pg/mL).
x-axis: free testosterone, pmol/L (high → low) · 650 pmol/L = 188 pg/mL, 150 pmol/L = 43 pg/mL
Symptoms track the absolute quantity of bioactive hormone — including bone density and muscle mass — far more tightly than they track age or total testosterone.
No deficiency symptoms. Peak cognition, maximal bone mineral density, optimal lean mass and daily erections.
High energy, strong recovery, active bone remodelling, insulin sensitivity restored.
Stable but unremarkable. Bone density maintenance only; body composition slowly drifts.
Fatigue, brain fog, slower recovery, visceral fat gain, early loss of bone mineral density.
Severe fatigue, sarcopenia, insulin resistance and accelerated osteoporosis. Highest fracture and type 2 diabetes risk.
A public health blind spot
The decline in male testosterone is close to linear, it shows no sign of flattening, and no European government treats it as a measured public health indicator. Insulin resistance, type 2 diabetes, muscle loss, osteoporosis and premature ageing all follow the same curve downwards — in the young as well as the old.
A population whose men are metabolically weaker, less muscular, more diabetic and more fragile in the skeleton is not only a healthcare cost. Recruitment fitness, workforce endurance and civil resilience rest on the same physiology. This is emerging across the Nordics and the entire Western world, and it is politically unmeasured.
When suboptimal free testosterone is never measured, its symptoms are re-labelled: burnout, depression, low self-esteem, chronic fatigue, prediabetes, early sarcopenia, poor sleep. Each gets its own prescription. The underlying cause is treated by no one.
Read against Dandona, Haider, T4DM and the bone-density literature, a substantial share of diabetes diagnoses and bone-loss diagnoses in men — and plausibly many diagnoses of low drive, low self-worth and depression — would not have occurred had those patients held optimal testosterone levels.
The European treatment gap
Most European protocols aim to bring a symptomatic man to roughly 20 nmol/L just after injection, then allow the level to decay across the interval to somewhere between 15 and 10 nmol/L before the next dose. That peak is roughly what a healthy top-10% man aged 60–80 carried in the 1970s and 80s — and the trough is below the level at which many men are symptomatic. The result is a cycle of brief improvement followed by relapse: enough treatment to be on therapy, not enough to be well.
≈ the top 10% of 60–80-year-old men in the 1970s/80s
Symptomatic range for a large share of men
The reference the protocol never aims at
| Period | Total T average | Total T top 10% | Free T average | Free T top 10% |
|---|---|---|---|---|
| 1970s (baseline) | 29 nmol/L | 35 – 45+ nmol/L | 520 pmol/L | 600 – 750 pmol/L |
| 1980s | 26 nmol/L | 32 – 40 nmol/L | 480 pmol/L | 550 – 680 pmol/L |
| 2026 (present) | 20 nmol/L | 25 – 33 nmol/L | 360 pmol/L | 450 – 580 pmol/L |
The consequences of the decline are skeletal and metabolic, not merely sexual. Both directions are documented: low testosterone drives insulin resistance and bone loss, and restoring it reverses them.
Typical changes reported in long-term optimisation and dose–response trials.
Long-term testosterone therapy increases spinal BMD, halting and partially reversing age-related bone loss.
Bhasin dose–response data: protein synthesis and myonuclear accretion scale linearly with hormone level.
Testosterone inhibits abdominal lipid storage and enhances lipolysis; waist circumference falls year over year.
Bone remodelling accelerates at upper-physiological levels; fracture risk falls with restored density.
Dandona, Haider and the T4DM trial: hormone status is a modifiable driver of diabetes risk.
Dhindsa & Dandona, Diabetes Care 2016 — testosterone acts as a potent insulin sensitiser.
Haider et al., 11-year registry: one-third of hypogonadal diabetic men stopped antidiabetic medication.
Two-year randomised trial in 1,007 men: testosterone plus lifestyle beat lifestyle alone.
Glycaemic control normalises as visceral fat falls and muscle mass returns.
Visceral fat is metabolically active: it secretes inflammatory cytokines and aromatase, which converts testosterone into estrogen. Testosterone falls further, muscle mass and resting metabolic rate drop, and insulin resistance deepens — a closed loop that diet alone rarely breaks.
BPA and phthalates raise SHBG production, binding and inactivating free testosterone even when total levels look acceptable.
Processed food and insulin resistance drive visceral fat, which secretes aromatase and converts testosterone into estrogen.
Sustained cortisol outcompetes sex hormone production through the pregnenolone steal mechanism.
Testosterone is secreted largely during deep sleep; shortened, fragmented sleep suppresses the overnight pulse.
A man can carry a "normal" total testosterone while high SHBG — which rises with age — drags free testosterone into hypogonadal territory, triggering fatigue, brain fog and metabolic dysfunction. The reverse also occurs: low total testosterone with very low SHBG can remain asymptomatic.
This is why any serious assessment measures total testosterone, free testosterone and SHBG together.
See what we measure