L-Tyrosine, image of fish, cheese, nuts containing L-Tyrosine

During fasting, each person responds differently to the mental and physical challenge of refraining from eating-especially in the beginning or when a person is fasting for the first time. One person may feel just fine; not bothered by hunger pangs, loss of energy or fluctuations in energy, and may remain focussed and alert. Other people will struggle with hunger cues, cravings, feeling lethargic, and become focused on the absence of food. L-Tyrosine (Tyrosine) is one of the nutritional supplements that can help support the body as it goes through adjustments in a fast.

Tyrosine is a non-essential amino acid produced by the body that helps build proteins. In addition, this amino acid plays a role in the production of enzymes, thyroid hormones, and the brain chemicals (neurotransmitters) that help nerve cells communicate.

While not all benefits of Tyrosine have been proven through research, health scientists are looking at how it might be used to address certain health conditions and support wellness. For example:

  • Tyrosine is particularly important in the production of the neurotransmitters epinephrine, norepinephrine, and dopamine-all of which have an effect on mood. During a fast when you might experience irritability, Tyrosine may support mood stability.
  • Tyrosine plays a role in circadian rhythm; it may be beneficial for helping people with narcolepsy and insomnia. During a fast, it may help with fatigue and restlessness.

Tyrosine is normally acquired from food such as poultry, fish, avocado, nuts, seeds, and yogurt. When following a fasting protocol, tyrosine can be taken as a tablet or capsule. Caution is required when taking a single amino acid supplement as this can affect the body’s nitrogen balance, have a detrimental effect on metabolism, kidney function, and the production of growth hormone and the skin pigment melanin. Children, pregnant and lactating women, and people who take thyroid medications or supplements should use Tyrosine under the supervision of a holistic healthcare provider.


Roky R., Iraki L., HajKhlifa R., Lakhdar Ghazal N., Hakkou F. “Daytime alertness, mood, psychomotor performances, and oral temperature during Ramadan intermittent fasting.” Ann Nutr Metab. 2000;44(3):101-7. doi: 10.1159/000012830. PMID: 11053895.

University of Rochester Medical Center Health Encyclopedia: Tyrosine. https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=19&contentid=Tyrosine

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