High tyrosine linked to shorter lifespans in men, large study suggests

A UK Biobank study of more than 270,000 participants found higher blood tyrosine levels linked to shorter life expectancy in men—potentially shaving nearly a year off lifespan—with no clear effect in women. After adjusting for related amino acids and factors, phenylalanine showed no association. Possible explanations include insulin resistance and sex-specific hormone pathways; the study does not test tyrosine supplements directly, but results suggest dietary protein or tyrosine levels could influence aging, warranting further research.