What is it and where does it come from?

L-tyrosine is a nonessential organic amino acid that is a building block of protein. It is an organic amino acid due to the presence of a carbon atom in its makeup.

It is a precursor of the neurotransmitter dopamine, as well as a precursor to the adrenal hormones norepinephrine and epinephrine.¹ The body can make L-tyrosine from the amino acid phenylalanine. L-tyrosine rich foods include animal meat, wheat products, oatmeal and seafood.

What does it do and what scientific studies give evidence to support this?

L-tyrosine may help athletes avoid overtraining, due to its ability to offset fatigue.²* Because L-tyrosine is a precursor of Dopamine, supplementing with L-tyrosine may heighten mental alertness, increase feelings of well being, and offset physical and mental fatigue.^3,4*

Who needs it and what are some symptoms of deficiency?

Everyone. Populations in need of L-tyrosine include: athletes, people trying to lose weight, and the elderly. Hard training athletes may benefit from supplementing with L-tyrosine as it helps to offset fatigue and stress associated with intense training.* L-tyrosine also serves to protect the integrity of the skin.* Melanin, a substance which acts to protect the skin when the epidermis has been exposed to ultraviolet light, is derived from L-tyrosine. If a shortage of melanin is present within the body [because of a lack of L-tyrosine], skin defenses will be compromised. Melanin, which is derived from L-tyrosine, chemically reacts with sunlight to form a protective shield that protects the deeper layers of skin tissue.*

People attempting to lose weight may benefit from supplemental L-tyrosine. The thyroid is responsible for the manufacture of T-cells. L-tyrosine influences the manufacture of thyroxin [T-cells], which influences basal metabolic rate. Because of this, L-tyrosine may prove effective for weight loss.*

Learn more about the benefits of L-Tyrosine on Clayton South's Health Facts.

How much should be taken? Are there any side effects?

At this time clear dosing guidelines have not yet been established, so it is best to do what is known as "tolerance mapping".

Take a small dosage for one week, note the benefits and the side effects, and increase the dosage until the benefits are maximized and the side effects minimized. Over time the two will converge and you will hit the optimal dose. This process is similar to "receptor mapping" for bodybuilders who use insulin and steroids.

Many protein powders on the market are fortified with amino acids, including tyrosine. With this in mind, pay particular attention to how much tyrosine you are ingesting from all sources. No side effects have been reported, although as with any amino-acid, overdose is a possibility. Individuals suffering from psychiatric conditions should consult a qualified medical practitioner prior to the use of supplemental L-tyrosine.

If you do not feel comfortable following the above-described procedure, it is always best to follow the directions as prescribed on the products label.