A large-scale study of over 270,000 people from the UK Biobank revealed a link between levels of the amino acid tyrosine and lifespan.[1][2] Higher levels of tyrosine are associated with shorter life expectancy in men.[1][2] Genetic analyzes have estimated that elevated levels of tyrosine can shorten the lifespan of men by almost one year.[1][2][4] No significant effect was observed in women.[1][2] The study also analyzed phenylalanine, a precursor to tyrosine, but after controlling for tyrosine, no association with lifespan was found in either men or women.[1][2][4] Men generally have higher levels of tyrosine than women.[1][2] The research was conducted by researchers from the University of Hong Kong and the University of Georgia.[1][2] The findings come from observational data and Mendelian randomization.[1][4]