Taurine

Taurine is a sulfur-containing non-proteinogenic amino acid synthesized in humans from cysteine via the cysteine sulfinic acid pathway, with dietary intake from animal foods — particularly shellfish, dark poultry meat, and fish — contributing substantially to circulating levels. It is highly concentrated in heart, skeletal muscle, retina, and neurons, where it acts as an osmolyte, modulates intracellular calcium handling, stabilizes mitochondrial membrane potential, and attenuates oxidative and endoplasmic-reticulum stress. A landmark 2023 paper by Singh et al. in Science reported that taurine levels in blood decline markedly with age in mice, monkeys, and humans, and that supplementing physiological amounts of taurine extended median lifespan in both male and female C57BL/6J mice (by approximately 10–12%) and improved several health metrics in middle-aged monkeys; mechanistic studies implicated suppression of cellular senescence, inflammation, DNA damage, and mitochondrial dysfunction. In humans, taurine association with longevity is observational only, and no interventional evidence for lifespan extension exists. Taurine is present in energy drinks and is sold as a supplement; at common doses it appears safe in adults, but long-term high-dose data in humans are limited.