A focus supplement may shorten men’s lives
A widely used supplement marketed for focus and mental performance may shorten lifespan in men. A large study involving more than 270,000 people linked higher blood levels of the amino acid tyrosine to a shorter lifespan in men, while no significant effect was seen in women.
Tyrosine is an amino acid found naturally in protein-rich foods such as meat, fish, and cheese. The body uses it to produce neurotransmitters including dopamine. It is also sold as a supplement, often promoted for improving focus and cognitive performance, which makes this finding particularly relevant for health-conscious consumers.
The study combined observational data with genetic analysis using a method known as Mendelian randomisation. This approach helps separate the effect of a genetically determined tendency towards higher tyrosine levels from other lifestyle factors. The researchers found that elevated tyrosine could potentially reduce male life expectancy by nearly a year. No significant effect appeared in women.
A sex difference that needs explaining
Why the effect appeared only in men remains unclear. Possible explanations include hormonal differences in how men and women metabolise tyrosine, or interactions with other metabolic pathways. The researchers describe the result as intriguing but stress that further research is needed.
This is an association study, meaning a direct causal link between tyrosine and shorter lifespan has not yet been proven. The genetic component strengthens the plausibility of the finding, but does not rule out alternative explanations.
What this means for supplement users
For people currently taking tyrosine supplements, this is a reason for caution, not alarm. The effect size is relatively small and the underlying mechanism is not yet understood. Waiting for more evidence before changing supplement habits seems prudent. Tyrosine from ordinary food was not separately assessed as a risk factor in this study.
Search terms to explore further: Mendelian randomisation life expectancy, tyrosine metabolism mortality, amino acid supplementation health risk