Mendelian Randomization Ties Higher Tyrosine to One-Year Shorter Male Lifespan in 270k UK Biobank Cohort

Researchers combined observational blood measurements with Mendelian randomization in the UK Biobank to test phenylalanine and tyrosine against all-cause mortality and predicted lifespan. After adjusting for confounders, only tyrosine remained robustly linked to reduced survival in men. The design leveraged random genetic assignment to strengthen causal inference over simple correlation, a step beyond most prior amino-acid longevity reports.

Existing coverage understates how the sex-specific pattern aligns with known male-female differences in catecholamine metabolism and oxidative stress. Tyrosine is the precursor for dopamine and norepinephrine; chronic elevation could accelerate vascular or inflammatory damage disproportionately in men. The study also notes men already exhibit higher average tyrosine, suggesting a partial mechanistic contribution to the longevity gap rather than a purely correlative finding.

The analysis did not examine supplement users or dietary intake directly, leaving open whether exogenous tyrosine drives the same risk. Follow-up work must test replication in independent biobanks, quantify dose-response thresholds, and incorporate longitudinal metabolomics to clarify whether the signal reflects lifelong exposure or late-life dysregulation.