Tyrosine 500 (Jarrow) Each bottle, 100 capsules. Each capsule, 500 mg of L-Tyrosine. Other ingredients include rice powder and magnesium stearate; gelatin capsule.

Tyrosine is a non-essential amino acid, found in cheese, soy products, chicken, fish, peanuts, almongs, avocados, bananas, milk pumpkin and sesame seeds, among other sources. It is a precursor to a number of neurotransmitters: chemicals found in the brain (and other tissues) that are involved in various functions as well as emotional states. Specifically, the class of catecholamines, which includes epinephrine, norepinephrine and dopamine, all use tyrosine in their synthesis.

Tyrosine has been investigated for its ability to affect various conditions. Some studies have shown a benefit for depression when tyrosine is used in conjunction with either tryptophan or its precursor, 5-HTP (5-hydroxytryptophan). Studies done in the 70s among individuals deficient in the amino acid showed some benefit, while a study using tyrosine alone for depression found no benefit, however, they did not combine it with 5-HTP or tryptophan. (NYBC will be carrying tryptophan shortly.)

People who cannot process the amino acid phenylalanine suffer from phenylketonuria. As a result, there bodies do not make tyrosine as most of the tyrosine produced in the body comes from this amino acid. Studies are somewhat mixed and it may simply be that a diet rich in tyrosine is adequate to address the deficit. It may also have a role in the treatment of vitiligo, a disorder of skin pigmentation that causes paler patches in dark-skinned individuals, however, there are no data yet to support or refute the notion. Due the regulation of serotonin that tyrosine may induce, it is also thought that it may be of benefit in managing the symptoms of premenstrual syndrome. So far, this has not been clinically evaluated.

Warnings: Do not take with MAO inhibitors (e.g., drugs like furazolidone (Furoxone), isocarboxazid: (Marplan®), isoniazid: (Laniazid®, Nydrazid®), rifampin (Rifamate®, Rimactane®/INH), moclobemide, pargyline (Eutonyl®), phenelzine (Nardil®), procarbazine (Matulane®), selegiline (Atapryl®, Deprenyl®, Eldepryl®) and tranylcypromine (Parnate®)). Some herbs may also act as MAO inhibitors; see http://www.home.caregroup.org/clinical/altmed/interactions/Herb_Groups/MAO_Inhibitors.htm

Do not use if you have a history of malignant melanoma. Also not advised for those with bipolar disorder nor for women who are pregnant, lactating or suspect a pregnancy.

Suggested use is to take 1-2 capsules immediately upon rising (empty stomach). You are encouraged to take it with a bit of juice as a carbohydrate source. For best effects, take with tryptophan or 5-HTP and use 3 times per day.