A common supplement ingredient may have some unwanted side effects. While many high performers use L-tyrosine to manage stress and improve their memory, new data suggests that they may be harming their long-term health by doing so.
A new study found that men with higher levels of tyrosine, which is commonly used to enhance cognitive function, had a shorter lifespan, raising questions about the efficacy of popular dietary supplements, including ashwagandha and lion’s mane mushroom.
Scientists from the University of Hong Kong and the University of Georgia analyzed data from over 250,000 individuals registered in the UK Biobank, a large health database that collects and stores medical information from volunteers. The study, which was published in Aging last fall, found that men who had genetically higher tyrosine levels lived, on average, one year less than those with normal levels.
The role of tyrosine
Tyrosine is a nonessential amino acid responsible for producing dopamine, adrenaline, and other brain chemicals that regulate your mood, focus, and stress response.
In the study, the researchers also focused on phenylalanine, the raw material the body converts into tyrosine, which is often found in protein-rich foods like meat, eggs, dairy, beans, and soy, and commonly added to dietary supplements and energy products, according to SciTechDaily.
Tyrosine’s link to longevity
To consider the role of tyrosine in longevity, the researchers analyzed the data with Mendelian randomization—a technique that uses genetic differences to test whether something actually causes a health outcome rather than just coinciding with it.
Initially, the study found that both increased levels of phenylalanine and tyrosine were linked to a high risk of an earlier death. But once the scientists accounted for the amino acid’s overlapping effects, only tyrosine consistently pointed toward a shorter lifespan.
The researchers found that this outcome was especially pronounced in men; higher tyrosine levels in this group were associated with a lifespan reduction of about 0.9 years. The association was less clear in women. Notably, the study said that men tend to have naturally higher levels of tyrosine than women, which may be the reason for the gap.
While more research needs to be done to understand why tyrosine may influence lifespan, scientists suggested that insulin resistance, the condition tied to diabetes and other age-related illnesses, may be a factor. A previous study of children linked high tyrosine levels to decreased insulin sensitivity, meaning the body had a harder time processing sugar, raising the risk of disease.
Additionally, tyrosine’s connection to stress may also be a factor. The interaction of adrenaline-related neurotransmitters with testosterone and estrogen may accelerate aging by activating stress pathways in the body.
Tyrosine’s rise in popularity
In recent years, dietary supplements have touted tyrosine’s health benefits. The popular L-tyrosine is said to ease stress and improve memory, making it particularly attractive to those who are in high-pressure environments, SciTechDaily said.
There is evidence supporting this. In one study, individuals performed better on a cognitive flexibility test when they took L-tyrosine supplements versus a placebo. Other research found that memory retention improved when subjects took the supplement during mentally demanding tasks.
Even though the ingredient may provide a short-term boost, this new research raises the question of whether the benefits are worth the potential long-term risk.
—Lucia Auerbach
This article originally appeared on Fast Company’s sister website, Inc.com.
Inc. is the voice of the American entrepreneur. We inspire, inform, and document the most fascinating people in business: the risk-takers, the innovators, and the ultra-driven go-getters that represent the most dynamic force in the American economy.