Tyrosine is a precursor (a preceding part of a biological process) of the neurotransmitters norepinephrine and dopamine, which regulate moods, among other things. Tyrosine is a non-essential amino acid, meaning that the body normally produces it. It acts as a mood elevator: conversely, a lack of adequate amounts of tyrosine leads to a deficiency of norepinephrine in the brain, which in turn can result in depression. Extra amounts of tyrosine in the diet may elevate brain levels of norepinephrine, improving neurotransmissions and doing away with depression.
Research into causes of organic depression continues. Vitamins B1, B6, phenylalanine in L, and DL forms, tyrosine, tryptophan and other psycho-chemicals are showing some notable benefits. However, because we humans are infinitely complicated, we can’t possibly expect to find only one cause of depression.
Tyrosine suppresses the appetite and helps to reduce body fat, it also aids in the production of melanin (the pigment responsible for skin and hair color) and in the functions of the adrenal, thyroid, and pituitary glands. It is also involved in the metabolism of the amino acid phenylalanine. Tyrosine attaches to iodine atoms to form active thyroid hormones. Not surprisingly, therefore, low plasma levels of tyrosine have been associated with hypothyroidism (low thyroid function). Symptoms of tyrosine deficiency can also include low blood pressure, low body temperature (such as cold hands and feet), and restless leg syndrome.
Supplemental L-Tyrosine has been used for stress reduction; research suggests it may also be helpful against chronic fatigue and narcolepsy. It has been used to help individuals suffering from anxiety, depression, allergies, and headaches, as well as persons undergoing withdrawal from drugs, including smoking and alcohol. It may also help people with Parkinson’s disease.
Natural sources of tyrosine include: almonds, avocados, bananas, dairy products, lima beans, pumpkin seeds, and sesame seeds. Tyrosine can also be produced from phenylalanine in the body. Supplements of L-tyrosine should not be taken at bedtime or with a high carbohydrate meal, no proteins so that it does not have to compete for absorption with other amino acids.
Persons taking monoamine oxidase (MAO) inhibitors, commonly prescribed for depression, should limit their intake of foods containing Tyrosine, and should not take any supplements containing L-Tyrosine, as it may lead to a sudden rise in blood pressure.
Recommended Dosage as per Health Canada Label Claims–Adults: Therapeutic Dosage: Take 1 capsule 8-15 times daily, on an empty stomach, or as directed by a health care practitioner. For occasional use only. Please note that these are therapeutic dosages from Health Canada; consult with your healthcare practitioner to see if these doses are appropriate for your personal healthcare needs.