Description

L-tyrosine is a widely used aromatic amino acid with an increasing market demand. This compound is a naturally occurring agent that acts as a precursor in the biosynthesis of monoaminergic neurotransmitters in the brain, such as dopamine, adrenaline, noradrenaline, and hormones like thyroxine and triiodothyronine[1].

Biological function

L-tyrosine is a nonessential amino acid. Nonessential means it is an amino acid that the body produces independently. It also occurs in cheese, milk, fish, chicken, soy, peanuts, and avocado. L-tyrosine has been shown to play essential roles in producing key neurotransmitters. The main benefits of L-tyrosine are related to its ability to replenish catecholamine levels in the brain, which can become depleted under stressful conditions. Research has demonstrated that L-tyrosine can help to prevent declined cognitive function under stressful, cognitively demanding conditions. Nootropic products have widely used this ability to influence cognitive function, mood, and sleep quality.

Weight Loss and L-Tyrosine

L-tyrosine supplements are believed to help with weight loss. Since it is a precursor to substances like epinephrine, norepinephrine, and dopamine, which are essential in regulating all metabolic processes, low levels of thyroid hormones can slow down your metabolism and change the way the body processes fat, leading to weight gain. L-tyrosine supplements can support the production of thyroid hormones to speed up your metabolism. L-tyrosine may be a good supplement choice for those trying to lose weight because, theoretically, it may help speed metabolism. However, it should only be considered for people who also suffer from symptoms such as fatigue and depression[2].

Side Effects

L-tyrosine supplementation is not recommended for persons diagnosed with (or on medication for) depression, abnormal blood pressure, or thyroid problems except with a doctor's consent. In particular, people with thyroid conditions such as an overactive thyroid should be cautious about taking tyrosine, as it might increase thyroxine levels too much.

Wrapping Up

The evidence on l-tyrosine's weight loss abilities is fragile. In 2017, a review of the levels of various amino acids and their correlation to weight found l-tyrosine among those whose increase coincided with obesity and decrease with weight loss.

References

[1] Guohua Li. “Enhancing the efficiency of L-tyrosine by repeated batch fermentation.” Bioengineered (2020): 852–861.

[2] Roman Bo\vca, Richard Imrich, Juraj \vStofko. “Ab initio study of molecular properties of l-tyrosine.” Journal of Molecular Modeling 29 8 (2023).