Jack Dorsey's Biohacker Protocol

Dorsey eats one meal per day on weekdays, typically in the evening — salmon and mixed vegetables is his reported staple. The fasting window runs roughly 23 hours. At this duration, autophagy (cellular self-cleaning) is measurably elevated, insulin sensitivity improves, and ketone production provides a stable alternative fuel source for the brain that many describe as cognitively cleaner than glucose-fuelled states.

Dorsey fasts entirely on weekends — water only from Friday evening through Sunday. At 48+ hours, autophagy peaks, stem cell regeneration increases, and IGF-1 (a growth factor associated with accelerated aging) drops significantly. This is an extreme intervention with real risks; electrolyte loss (sodium, potassium, magnesium) is the primary physiological challenge during multi-day fasts.

Dorsey uses a CGM (Levels Health) to test exactly how his blood glucose responds to specific foods and meal timings. The data routinely surprises people — foods assumed to be safe cause large glucose spikes in some individuals; foods assumed harmful are neutral in others. This kind of personalised metabolic feedback removes guesswork from dietary decisions.

Dorsey's most-discussed habit. Cold water immersion at this temperature triggers a norepinephrine release of approximately 300% above baseline — a profound alertness and mood driver that peaks within minutes and persists for hours. It also activates cold shock proteins (RBM3) involved in synaptic repair, and provides a consistent mental resilience practice. He does this before anything else in the morning.

Heat exposure activates heat shock proteins (HSP70, HSP90) that act as molecular chaperones — refolding misfolded proteins before they can aggregate. Repeated sauna use is associated in epidemiological data with a 40% reduction in all-cause cardiovascular mortality at 4+ sessions per week. Dorsey uses infrared rather than traditional sauna; the mechanisms are similar, the hardware is more accessible.

The physiological benefit of alternating cold and heat is primarily vascular — cold vasoconstricts, heat vasodilates, and the alternation acts as a pump for the lymphatic system and peripheral circulation. Dorsey uses hot-cold alternation as part of his recovery protocol, particularly after exercise. The parasympathetic rebound after cold immersion is also a reliable mood stabiliser.

Dorsey has done multiple 10-day silent Vipassana retreats and structures his daily practice around the same technique — body scanning, breath observation, non-reactive awareness. At 2 hours per day this is an extreme commitment, but even 20 minutes of daily mindfulness practice has demonstrated structural changes in the prefrontal cortex within 8 weeks. Dorsey credits the practice with his capacity for high-stakes decision-making under pressure.

Dorsey does a 10-day Vipassana silence retreat (no talking, no screens, no reading) once a year. The immersive format produces changes in default mode network activity and amygdala reactivity that persist for months afterward. He describes the retreat as the single most important thing he does for his mental clarity. Goenka-tradition centres offer this free of charge worldwide.

Unlike Bryan Johnson's 30+ compound stack, Dorsey takes a deliberately minimalist approach to supplementation — he prefers to use lifestyle interventions (fasting, cold, heat, meditation) as the primary levers and supplements to fill specific nutritional gaps. His stack is shorter but each compound is well-chosen. The three below are the highest-evidence choices given his OMAD diet and San Francisco latitude.

Dorsey follows the same protocol as Andrew Huberman — outdoor light (not through a window, not through sunglasses) within the first hour of waking to set the circadian clock and trigger the cortisol morning pulse. Even overcast sky delivers 10,000+ lux, enough to anchor the circadian rhythm; indoor lighting rarely exceeds 400 lux. The absence of sunglasses is deliberate — UV wavelengths reaching the eye (not the skin) are the active signal.

Dorsey walks 5 miles to work rather than driving or taking transport — roughly 90 minutes of Zone 1 low-intensity movement that doubles as his morning light exposure and bilateral stimulation practice. Walking has a well-documented anxiolytic effect distinct from higher-intensity exercise, and the bilateral, rhythmic nature of walking has been hypothesised to process emotional content similarly to EMDR.

Dorsey stopped coffee entirely and uses cold immersion as the alertness driver — the 300% norepinephrine spike from a 3-minute ice bath produces a clarity and focus onset comparable to caffeine but without adenosine receptor antagonism, tolerance buildup, or the afternoon cortisol disruption that caffeine causes. The cold response is also faster — peak effect within 10 minutes versus 30–45 minutes for coffee.