Taurine

Taurine is a naturally occurring sulfur-containing amino acid found abundantly in the brain, retina, heart, and reproductive organ cells, as well as in meat and seafood. ^[1] It is an organic osmolyte involved in cell volume regulation and provides a substrate for the formation of bile salts, and although it is one of the few amino acids not incorporated into proteins, it is one of the most abundant amino acids in the brain, retina, muscle tissue, and organs throughout the body. ^[2] In humans taurine can be synthesized endogenously, being derived from cysteine, one of the four common sulfur-containing amino acids alongside methionine and homocysteine. ^[3]

Taurine is regarded as a cytoprotective molecule due to its ability to sustain the normal electron transport chain, maintain glutathione stores, upregulate anti-oxidant responses, increase membrane stability, eliminate inflammation, and prevent calcium accumulation. ^[4] In the heart, where taurine content is approximately 20 mM (roughly 100 times the plasma concentration), it regulates intracellular ion dynamics and calcium handling and acts as an antioxidant. ^[5] Taurine supplementation protects against pathologies associated with mitochondrial defects and helps maintain mitochondrial function, acting as more than just an antioxidant. ^[6]

A systematic review and meta-analysis of 20 randomized controlled trials pooling 808 participants found that taurine significantly reduced systolic blood pressure and diastolic blood pressure and increased left ventricular ejection fraction, with no significant adverse effects compared with controls. ^[7] Evidence from both human and animal studies indicates that taurine may have beneficial cardiovascular effects, including blood pressure regulation, improved cardiac fitness, and enhanced vascular health, making it an intriguing candidate for potential anti-aging strategies. ^[8] It has been reported that taurine declines with age and is associated with lifespan in worms and mice as well as with healthspan in mice and monkeys, though in humans the relationship between dietary taurine deficiency and cardiomyopathy is not yet clear. ^[5] Taurine has been proposed for classification as a conditional vitamin, reflecting its dual role in both immediate survival and long-term health. ^[9] The effectiveness of taurine as an ergogenic aid remains controversial, with limited and varied findings prohibiting definitive conclusions regarding its efficacy on aerobic and anaerobic performance and metabolic outcomes.

Considering its broad distribution, its many cytoprotective attributes, and its functional significance in cell development, nutrition, and survival, taurine is undoubtedly one of the most essential substances in the body. ^[2] In some species such as cats and foxes that have low taurine biosynthetic capacity, dietary taurine deficiency can lead to disorders such as dilated cardiomyopathy and blindness. ^[5] Taurine deficiency in humans is associated with cardiomyopathy, renal dysfunction, developmental abnormalities, and severe damage to retinal neurons. ^[2]