About Citrulline

Citrulline is a naturally occurring amino acid, which means it does not have to be obtained through our diet as it is synthesized from other amino acids in the body. Its main precursor is the amino acid glutamine. Citrulline has many important roles in the body but unlike some amino acids, it is not used to build proteins.

Citrulline plays an important role in the urea cycle, which is a process whereby it rids our body of ammonia (an extremely toxic substance for the central nervous system), which then becomes urea which is eliminated through our urine. Additionally, citrulline helps dilate blood vessels, boosting the body’s nitric oxide production. This helps arteries work more efficiently and thus improves the blood flow throughout our entire body. It also plays an important role in stimulating our immune system.

Citrulline may also help lower high blood pressure in people with hypertension but individuals with low blood pressure should be careful with taking citrulline supplements.

Taking citrulline supplements is thought to improve athletic performance but studies have not shown this effect on well-trained athletes. Also, the supplement might impact how certain drugs work in the body. It is therefore always recommended to seek advice from a doctor or health care professional.

Biostarks reference ranges for citrulline

• Citrulline (Cit-S): 17-96 umol/L

Scientific references:

• Bahri, S. et al. (2013). Citrulline: from metabolism to therapeutic use. Nutrition, 29(3), 479-484.
• Aguayo, E., Martínez-Sánchez, A., Fernández-Lobato, B., & Alacid, F. (2021). l-Citrulline: A non-essential amino acid with important roles in human health. Applied Sciences, 11(7), 3293.
• Papadia, C., Osowska, S., Cynober, L., & Forbes, A. (2018). Citrulline in health and disease. Review on human studies. Clinical Nutrition, 37(6), 1823-1828.
• Breuillard, C., Cynober, L., & Moinard, C. (2015). Citrulline and nitrogen homeostasis: an overview. Amino acids, 47(4), 685-691.