Dietary supplements for improving concentration, memory, and mental performance have in recent years become especially sought-after, with sales reaching billions of dollars worldwide. One of the most common ingredients in these supplements is tyrosine—an amino acid that the body uses to produce neurotransmitters such as dopamine, norepinephrine, and epinephrine. But now, a new study raises concern that high levels of tyrosine may have a worrying effect—at least among men.
Researchers from the University of Hong Kong and the University of Georgia in the United States examined a possible link between two amino acids—phenylalanine and tyrosine—and life expectancy. The findings, published in the scientific journal Aging, indicate that high levels of tyrosine in the blood are associated with a shorter life expectancy in men, although no significant effect was found in women.
What is tyrosine anyway, and why is it so popular?
Tyrosine is an amino acid that the body uses as a raw material to produce important neurotransmitters—dopamine, norepinephrine, and epinephrine. These neurotransmitters affect cognitive performance, responses to stressful situations, as well as mood regulation. Therefore, tyrosine is often included in products marketed to improve mental focus, reduce stress, and increase energy levels.
The amino acid appears naturally in protein-rich foods such as meat, dairy products, eggs, and legumes. But in recent years it has become a common ingredient in dietary supplements, especially among people who wish to improve their mental performance. However, despite the popularity of this ingredient, until now relatively little has been known about the long-term effects of tyrosine on aging processes.
To examine this question, the researchers analyzed information on more than 270,000 people in the British UK Biobank database. They used observational data together with genetic techniques to investigate how levels of phenylalanine and tyrosine in the blood are linked to mortality and estimated life expectancy.
The initial results suggested that perhaps both amino acids increase the risk of early death, but when the findings were examined in depth, it became clear that only tyrosine continued to show a strong association with life expectancy. The researchers also found that men with high tyrosine levels may experience a shortening of nearly one year in life expectancy, while women, as noted, are not affected by this.
Why are men specifically affected by tyrosine?
The precise mechanisms behind the effect of tyrosine are still being studied, but experts suggest several possible explanations. Tyrosine is involved in processes of insulin resistance and in the production of stress-related neurotransmitters. Insulin resistance increases the risk of many diseases associated with aging, foremost among them diabetes.
It is also possible that tyrosine’s involvement in the production of stress hormones triggers a different biological response in men than in women, especially due to differing hormonal effects between the sexes. In addition, the data examined show that tyrosine levels in men are higher to begin with, which may explain at least part of the gender gap in life expectancy.
So what does this mean for dietary supplements in general and for tyrosine in particular?
Although tyrosine is generally marketed as a supplement for improving concentration and mental performance, the study raises concerns about its long-term impact on life expectancy. It is important to note that the researchers did not directly examine the effect of supplements containing tyrosine, but only the statistical relationship between blood tyrosine levels and life expectancy.
The experts are not calling to stop using supplements, but rather to understand that, in general, an ingredient that helps in the short term does not always benefit us in the long term. Tyrosine does contribute to mental sharpness and to managing stressful situations, but its effect on the body may be far more complex than we currently understand.
The researchers conclude that further research is needed to examine the effects of tyrosine over time, especially in the contexts of aging and metabolic health. Until then, they settle on a cautious recommendation: Before starting to use a new supplement, especially one that affects brain chemistry, it is advisable to understand the full picture and consult with a medical professional. In other words, tyrosine may be considered a natural supplement for improving mental performance, but natural does not necessarily mean safe—and sometimes even the natural can be dangerous.