High Tyrosine Levels Linked to Shorter Lifespan in Men, Study Finds

New research suggests a link between elevated levels of the amino acid tyrosine and reduced life expectancy in men, highlighting potential sex-specific differences in longevity strategies.

The Role of Phenylalanine and Tyrosine

Phenylalanine and tyrosine are essential amino acids crucial for metabolism and brain function. Found in protein-rich foods and dietary supplements, their long-term effects on aging have remained largely unclear until recently. Tyrosine is a precursor to neurotransmitters like dopamine, which play a vital role in mood, motivation, and cognitive function, making it a key area of interest in aging research.

Large-Scale Study Reveals Key Findings

A study published in Aging-US on October 3, 2025, analyzed data from over 270,000 participants in the UK Biobank. Researchers, led by Jie V. Zhao, Yitang Sun, Junmeng Zhang, and Kaixiong Ye from the University of Hong Kong and the University of Georgia, used both observational data and genetic analyses to investigate the association between blood levels of phenylalanine and tyrosine and overall mortality.

While both amino acids initially showed a correlation with higher mortality risk, only tyrosine consistently demonstrated a potentially causal relationship with reduced life expectancy specifically in men. Genetic modeling estimated that elevated tyrosine levels could shorten men’s lifespan by nearly one year. No significant effect was observed in women.

Why the Difference? Potential Biological Explanations

Researchers are investigating the underlying reasons for this sex-specific association. One possibility involves insulin resistance, a condition linked to age-related diseases. Tyrosine is as well involved in the production of stress-related neurotransmitters, which may impact metabolic and hormonal pathways differently in men, and women. Variations in hormone signaling could explain why the effect was primarily observed in men.

Notably, men generally have higher tyrosine levels than women, which may contribute to the existing lifespan gap between the sexes. The study also found that phenylalanine showed no association with lifespan in either men or women after controlling for tyrosine levels.

Implications for Supplement Use and Dietary Adjustments

Tyrosine is a popular supplement marketed for its cognitive-enhancing properties. However, these findings raise questions about its long-term health effects.

The researchers suggest that individuals with high tyrosine levels might benefit from dietary adjustments, such as moderating overall protein intake, to potentially lower tyrosine levels and support healthier aging.

Future Research Needed

Further research is necessary to confirm these results and determine whether targeted dietary or lifestyle changes can safely reduce tyrosine levels and promote longevity.