Tyrosine tied to nearly one year less life in men
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- Researchers at the University of Hong Kong and University of Georgia analyzed UK Biobank data from over 270,000 people and found higher tyrosine levels consistently associated with shorter lifespans in men.
- The study, published in the journal Aging-US and led by Jie V. Zhao, Yitang Sun, Junmeng Zhang, and Kaixiong Ye, used both observational analysis and Mendelian randomization to test for causal effects.
- Genetic analyses estimated that elevated tyrosine levels could shorten men's lifespan by nearly one year, while no significant association appeared in women.
- Phenylalanine, the other amino acid studied, showed no association with lifespan in either sex once tyrosine was statistically controlled for.
- The researchers noted that men generally have higher tyrosine levels than women, which may partially explain the long-observed gap in average lifespan between the sexes.
- The study did not directly test tyrosine supplements — only naturally occurring blood levels — so findings do not prove supplements are harmful, though they flag elevated tyrosine as worth further investigation.
- Proposed mechanisms include insulin resistance, disruption of stress-response neurotransmitters like dopamine and norepinephrine, and hormone-related pathways that may function differently in men and women.
Why it matters: A 270,000-person UK Biobank study using Mendelian randomization provides stronger-than-usual causal evidence that tyrosine — a protein building block and common nootropic ingredient — may shorten male longevity by up to a year. Supplement users and the broader brain-health market now face a credible new question about long-term safety, though the study measured natural blood levels, not pills, and the researchers stress more work is needed.
