4 Blood Markers GPs Miss in Founders

Reference ranges are statistical: they describe where 95% of the tested population falls. That population includes sedentary, sleep-deprived, metabolically average people. A founder running a €3M company while making 80+ judgment calls a week is not the reference population. Their bar should be optimal, not normal. Peter Attia has been making this point for years, and he is right.

1. Free testosterone (not total)

Total testosterone is the headline number. Free testosterone is the bioavailable fraction your brain and muscle actually use.

A founder can have "normal" total testosterone and low free testosterone if SHBG (sex hormone binding globulin) is elevated. This is common in chronic stress and elevated insulin states. Operator threshold for males 35–50: free testosterone in the upper third of the reference range. Lower than that and drive, decision energy, and recovery all measurably degrade.

2. Ferritin

Ferritin reflects iron stores. The lab reference range typically starts at 30 ng/dL. The cognitive performance threshold is closer to 70 ng/dL.

Below that, oxygen delivery to the brain is suboptimal, even if you are not anemic. Symptoms: morning fog, declining endurance, "tired but wired" pattern. This is particularly common in male founders over 40 due to blood donation or low red-meat intake, and almost universal in female founders.

3. Free T3

Most thyroid screens stop at TSH. TSH can be "normal" while free T3 (the active thyroid hormone your cells use) is suppressed. Chronic stress and aggressive caloric restriction both lower free T3 without moving TSH.

Operator threshold: free T3 in the upper half of the reference range. Suppressed free T3 looks identical to "low motivation" and "founder burnout" to anyone not measuring it.

4. Fasting insulin

Fasting glucose alone misses early metabolic dysfunction. Fasting insulin catches it years earlier. Operator threshold: under 7 µIU/mL. Above 10 means you are insulin-resistant before any glucose abnormality shows up.

Cognitive consequence: post-prandial energy crashes, reduced fasted morning clarity, and declining gym recovery. A founder will explain all of this as "getting older" instead of treating it as a metabolic signal.

• hsCRP systemic inflammation. Optimal < 1.0 mg/L.
• Vitamin D (25-OH) at northern latitudes, almost universally suboptimal. Target 40–60 ng/mL.
• HbA1c 90-day glucose average. Optimal < 5.4%.
• ApoB cardiovascular risk marker. Better than LDL alone for long-horizon decisions.
• Homocysteine methylation status, cognitive risk marker. Optimal < 8 µmol/L.

Four steps, in order:

1. Run the panel above. Most labs in Finland, Sweden, the UK, and Germany will run all of it as a private order.
2. Compare against operator thresholds, not reference ranges.
3. Address the worst-scoring marker first with one intervention (not five). Re-test in 12 weeks.
4. Tie the result back to your HRV trend and decision-quality self-rating. Biology data without behavioral data is half a picture.

Attia gives you the framework. Huberman gives you the protocols. Robbins and Wim Hof give you state. None of them (and they don't claim otherwise) read your specific lab values and tell you which marker to fix first inside the calendar of a working founder. That translation step is the work. The Founding Member cohort installs it over roughly 6 months.