A common amino acid found in protein-rich foods and popular focus supplements may be linked to a shorter life expectancy in men, according to a study published in Aging.
Analyzing health and genetic data from over 270,000 UK Biobank participants, researchers found that higher blood levels of tyrosine were tied to a lifespan reduction of nearly one year in men, with no significant impact seen in women.
What Is Tyrosine?
Tyrosine is an amino acid used to build proteins and synthesize dopamine—a key neurotransmitter for focus, mood, and motivation. Because of these cognitive roles, it is widely marketed in dietary supplements aimed at mental performance.
Key Takeaways
- Men Only: High tyrosine levels correlated with a shorter lifespan in men, but had no notable effect on women.
- Independent Impact: The link remained strong even after controlling for related amino acids like phenylalanine.
- Higher Baseline in Men: Men naturally have higher baseline tyrosine levels than women, which may contribute to sex-based differences in longevity.
Potential Biological Pathways
Scientists suggest two potential reasons for the connection:
- Insulin Resistance: Higher tyrosine levels correlate with decreased insulin sensitivity, a factor in age-related metabolic decline.
- Stress Pathways: Tyrosine helps produce stress-response hormones, which can affect male and female biological systems differently.
What This Means for Consumers
Because the study measured existing blood concentrations rather than testing supplements directly, the findings do not prove taking tyrosine causes early death. However, they raise questions about long-term elevated levels, prompting researchers to caution against drastic dietary shifts until further studies are conducted.
