WHAT IS HISTIDINE? Histidine Powder is an essential amino acid that is a popular addition to pre-workout formulas. BULK POWDERS™ Histidine provides a pure source of the essential amino acid, L Histidine. Histidine is an essential amino acid. By virtue of being an essential amino acid, Histidine can't be manufactured by the body & must be obtained from the diet or supplement…[1000]