L-citrulline malate and gamma-ethylamino-L-glutamic acid, commonly called citrulline and theanine, respectively, are amino acids available as dietary supplements. Both citrulline and theanine are nonessential amino acids; your body is able to manufacture them from food sources. Although no evidence suggests you should take citrulline and theanine together, no evidence advises that you cannot do so.
Citrulline
Your body manufactures citrulline from glutamine, an essential amino acid you must obtain from your food. The body then converts some citrulline to L-arginine, another amino acid. Some proponents of citrulline supplements take them to raise arginine levels. The body also uses citrulline to convert ammonia into urea, which is then excreted in the urine. Although citrulline is used to enhance athletic performance, no evidence supports such use, according to the website Healthlibrary.epnet.com. Citrulline has no reported side effects.
Citrulline and Short Bowel Syndrome
An article in the June 2007 issue of the “Journal of Nutrition” reported that citrulline may be useful as a marker of intestinal failure in a condition called short bowel syndrome. The small intestines normally release citrulline into the body. If the intestine is surgically shortened because of damage or disease, citrulline production decreases. Citrulline supplementation may be helpful in short bowel syndrome to stimulate the synthesis of muscle proteins and help prevent malnutrition, which is one of the complications of short bowel syndrome.
Theanine
Theanine is a nonessential amino acid found in tea leaves from the Camellia sinensis plant and from the edible mushroom Boletus badis, also known as the Bay Boletus. There is limited clinical information that theanine may support the immune system, have cardiovascular effects and be a cancer preventative, according to the website Drugs.com. There are no known contraindications, and side effects are limited to a few reports of dizziness, headache and gastrointestinal symptoms.
Theanine and Anxiety
There is some evidence that theanine may act as an anti-anxiety agent. A study in the September 2008 “Asia Journal of Clinical Nutrition” found that theanine could relax the mind without making people drowsy. Young, healthy study participants took 50 milligrams of theanine or a placebo. The brain waves of study participants after theanine showed an increase in alpha waves -- a sign of relaxation -- with no decrease in alertness.
Theanine and the Brain
Research in the 2006 “Journal of Herbal Pharmacology” reported that animal studies suggest theanine can increase chemicals in the brain called neurotransmitters. Serotonin, dopamine and GABA promote relaxation; all were increased by supplemental theanine. Researchers also noted that behavioral studies in animals indicate theanine may improve learning and memory. Theanine was also shown to help protect the brains of animals used in this study.
Citrulline and Theanine
Citrulline malate is the most commonly sold form of citrulline supplement. Dosage recommendations vary from 6 to 18 grams of citrulline a day. There is no dosage recommendation for theanine, according to Drugs.com. Although citrulline and theanine are both amino acids, the similarities end there. Each has a different mechanism of action in the human body, and there is no evidence that they interact with each other. There is no reason to think they should not be taken together, but if you have questions or concerns, consult a health care professional.
References
- Healthlibrary.epnet.com: Citrulline
- Journal of Herbal Pharmacotherapy: The Neuropharmacology of L-Theanine(N-Ethyl-L-Glutamine): A Possible Neuroprotective and Cognitive Enhancing Agent
- Journal of Nutrition: Citrulline: A New Player in the Control of Nitrogen Homeostasis
- Drugs.com: L-Theanine
- Asia Pacific Journal of Clinical Nutrition: L-theanine, A Natural Constituent in Tea, and its Effect on Mental State
Member Comments