Hisidine is a semi-essential amino acid.
A dietary source of histidine generally is not needed by adults, since they make enough hisidine in their bodies; consequently, histidine is not considered essential for men and women.
During periods of growth, such as childhood, histidine is not made in sufficient quantities and a dietary source is required; consequently, hisidine is an essential amino acid for children.
Arthritis: Some individuals with rheumatoid arthritis have low levels of histidine, but it is unknown whether these low levels are a cause or a result of the disease.
Deficiency Symptoms: Adults fed diets deficient in histidine might develop dry scaly skin, irritability, and short-term memory loss.