Citrulline as a therapeutic supplement
Citrulline is a nonessential amino acid produced by the body, primarily derived from the essential amino acid glutamine. It is known for its conversion into L-arginine, which plays a crucial role in various physiological processes, including the urea cycle. Citrulline has gained attention as a therapeutic supplement, particularly in enhancing sports performance, where it may help increase blood flow to muscles, reduce fatigue, and improve endurance. Additionally, some studies suggest potential benefits for conditions such as Alzheimer's disease, erectile dysfunction, heart disease, and muscle wasting. While generally considered safe, especially when sourced from foods like watermelon, citrulline supplementation has not been extensively regulated or tested by health authorities. Recommended dosages typically range from 6 to 18 grams daily, often in the form of citrulline malate. Prospective users are advised to consult healthcare professionals to understand possible effects and side effects, as individual responses may vary.
Citrulline as a therapeutic supplement
DEFINITION: A natural substance of the human body used as a supplement to treat specific health conditions.
PRINCIPAL PROPOSED USE: Enhancing sports performance
OTHER PROPOSED USES: Alzheimer’s disease, fatigue, male sexual dysfunction, reducing blood pressure, heart disease, sickle cell disease, muscle wasting
Overview
Citrulline is a nonessential amino acid, meaning the body can manufacture it from other nutrients. Within the body, citrulline is converted to the amino acid L-arginine. Some of the proposed uses of citrulline supplements are based on raising arginine levels. Citrulline also plays a role in a physiological process called the urea cycle, in which toxic ammonia is converted to urea.
Requirements and Sources
The body manufactures citrulline from the essential amino acid glutamine. A deficiency of citrulline is unlikely to occur. Citrulline can be found in sources such as watermelon.
Therapeutic Dosages
A typical dose of citrulline is 6 to 18 grams daily. It is commonly sold as citrulline malate.
Therapeutic Uses
The proposed uses of citrulline are based on the fact that the body converts citrulline to the amino acid arginine. Some claim that citrulline supplements are more effective at raising arginine levels than arginine supplements. However, this is not scientifically based. Still, emerging scientific studies in the twenty-first century do indicated citrulline may be effective in treating specific medical conditions. Two studies found that supplementation with citrulline improved erectile function in men. Although these studies were on a smaller scale, they indicate citrulline may hold promise for improving erectile function and sexual satisfaction.
Emerging studies attesting to citrulline's effectiveness have allowed it to attain popularity in certain athletic communities, such as among bodybuilders. Many enthusiasts are attracted to claims of its ability to enhance performances, where even a slight advantage can be consequential. Scientific research has increasingly supported claims that citrulline may increase blood flow to muscles, reduce fatigue, and improve endurance.
Very preliminary studies conducted in France in the late 1970s hint that citrulline may improve mental function in people with Alzheimer’s disease and also reduce general fatigue. However, these studies were not conducted at modern scientific standards. Studies have indicated that citrulline may help reduce blood pressure by increasing nitric oxide production and improving blood vessel function. Other conditions believed to receive benefits from citrulline supplementation include sickle cell disease, muscle wasting, diabetes, cognitive impairment, and intestinal problems.
Safety Issues
As a naturally occurring amino acid, citrulline is believed to be safe. However, maximum safe doses in young children, pregnant or nursing women, and people with severe liver or kidney disease have not been established. Prospective consumers should understand that as a supplement, citrulline is not a drug regulated by the Food and Drug Administration. As such, citrulline is not tested for safety or effectiveness. It falls upon the consumer to consult with healthcare providers over potential side effects or whether the supplement will have the effect they are paying to receive.
Bibliography
Bendahan, D., et al. "Citrulline/Malate Promotes Aerobic Energy Production in Human Exercising Muscle." British Journal of Sports Medicine, vol. 36, 2002, pp. 282-289.
Cormio, Luigi, et al. "Oral L-Citrulline Supplementation Improves Erection Hardness in Men with Mild Erectile Dysfunction." Urology, vol. 77, no. 1, 2011, pp. 119-22, doi.org/10.1016/j.urology.2010.08.028. Accessed 14 Sept. 2024.
Hickner, R. C., et al. "L-citrulline Reduces Time to Exhaustion and Insulin Response to a Graded Exercise Test." Medicine and Science in Sports and Exercise, vol. 38, 2006, pp. 660-666.
"L-arginine." Mayo Clinic, 10 Aug. 2023,www.mayoclinic.org/drugs-supplements-l-arginine/art-20364681. Accessed 14 Sept. 2024.
Lefton, Jennifer. "Benefits of Citrulline and Whether It’s Safe to Take" Verywell Health, 14 Sept. 2024, www.verywellhealth.com/citrulline-4774848. Accessed 14 Sept. 2024.
Miller, Kelli. "L-citrulline: Uses and Risks." WebMD, 6 Sept. 2023, www.webmd.com/vitamins-and-supplements/l-citrulline-uses-and-risks. Accessed 14 Sept. 2024.
"What is Citrulline?" Cleveland Clinic, 7 Feb. 2023, health.clevelandclinic.org/citrulline-benefits. Accessed 14 Sept. 2024.