Histidine may be useful for treatment of mental disorders as well as certain types of sexual dysfunction.

Excessive levels of histidine have been linked to psychological disorders including anxiety and schizophrenia.  Low levels of histidine may contribute to the rheumatoid arthritis and deafness due to acoustic nerve damage.

Histidine is important for correct sexual functioning, because it gets converted into histamine which is required to stimulate sexual arousal. When taken together with Vitamin B3 (niacin) and vitamin B6, sexual pleasure may be increased by boosting histamine levels throughout the body.

Histamine also helps the immune system know when the body is experiencing an allergic reaction. It is involved in the production of much needed, digestive, gastric juices.

Probably because of its roll in protecting the nerves, Research suggests histidine may, protect against radiation damage, and the removal of heavy metals from the system. It is used in the production of both red and white blood cells.

Histidine is found in grains such as rice, wheat, and rye, as well as meat and dairy.

The chronically ill, post-surgery, or arthritic individual may wish to consider supplementation with this amino acid.

Warning
If you have manic (bipolar) depression you should not take supplemental histidine without first consulting your physician. Anyone with liver or kidney disorders should not take histidine without first consulting their primary health care provider. Amino acid supplementation may disrupt the Krebs cycle by which toxins are eliminated from the liver and kidneys. It may push nitrogen levels out of balance.
Always ensure your zinc levels are sufficient if supplementing with Histidine.