Taurine is a sulfur-containing amino-acid-like molecule (not protein-incorporated). Endogenously synthesized from cysteine; widely depleted with age.
Mechanism — Modulates calcium handling in cells (especially cardiac), supports mitochondrial function, acts as a weak GABA-A agonist, conjugates bile acids, and has direct antioxidant activity. Lifespan extension in primate studies on supplementation.
Use case — General longevity protocol (3-6 g/day), cardiovascular support, exercise endurance, sleep quality (1-2 g before bed). Cheap and well-tolerated.
Caveats — Don't take during the day if it produces sleepiness. Bipolar caution — GABA modulation. Energy drinks contain taurine in tiny amounts — not equivalent to therapeutic dosing.