L-histidine is a semi-essential amino acid meaning that it is produced by the body but not in vast amounts. L-histidine aids in the synthesis of haemoglobin (1), tissue repair (2) and enhancing the immune system (3).
1 – Noort, D., Hulst, A. G., Trap, H. C., de Jong, L. P., & Benschop, H. P. (1997). Synthesis and mass spectrometric identification of the major amino acid adducts formed between sulphur mustard and haemoglobin in human blood.Archives of toxicology, 71(3), 171-178.
2 – Babizhayev, M. A., Seguin, M. C., Gueyne, J., Evstigneeva, R. P., Ageyeva, E. A., & Zheltukhina, G. A. (1994). L-carnosine (beta-alanyl-L-histidine) and carcinine (beta-alanylhistamine) act as natural antioxidants with hydroxyl-radical-scavenging and lipid-peroxidase activities. Biochem. J, 304, 509-516.
3 – Li, P., Yin, Y. L., Li, D., Woo Kim, S., & Wu, G. (2007). Amino acids and immune function. British Journal of Nutrition, 98(02), 237-252.