In a nine-month self-experiment on taurine supplementation, the impact on various biomarkers was assessed. Taurine, a dietary amino acid, plays a crucial role in biological processes, with levels decreasing with age. Supplementing taurine has shown positive effects on health and longevity in animal studies. Human trials have shown mixed results, but safety is not in question. One self-experimenter, a vegetarian in his 50s, took 3 grams of taurine daily and saw improvements in phenotypic age and several biomarkers. Notably, lymphocyte percentage increased, largely due to a decrease in neutrophil count. Oxidized LDL, a marker of oxidative stress, also decreased. While this is just one anecdotal report, further research on taurine supplementation’s effects on biological aging could be valuable, given its affordability and safety.