L-citrulline supplements have been shown to increase Nitric Oxide and Growth Hormone levels, which may support muscle growth for bodybuilders.
Such supplements are used to enhance physical performance and increased levels of arginine in the blood.
Citrulline is a non-essential amino acid that is an important intermediate in the urea cycle, functioning along with Arginine and Ornithine to rid the body of ammonia.
Citrulline, being a precursor of Arginine, provides readily available source material for Arginine production, which in turn, can be used for the production of Nitric Oxide (NO), which plays a fundamental role in vascular function and blood flow.
Citrulline therefore, not only supports detoxification pathways, but also the production of Nitric Oxide, which results in a healthy cardiovascular system.
The body converts L-citrulline to L-arginine, another type of amino acid, which improves blood flow, and has been shown to help people with heart disease or clogged arteries because of its vessel-widening abilities.
Thus, as a Nitric Oxide booster, citrulline supplements may improve circulation throughout the body and boost nutrient delivery to muscle cells.
It is also taken as a pre-workout supplement to improve muscle pumps by bodybuilders or weightlifters that lift heavyweights.
As a supplement, L-citrulline is typically sold in the form of Citrulline Malate and can be purchased in bulk powder, tablet or capsule form.
It also occurs naturally in certain foods, with watermelon being the best L-citrulline food source.
Cucumbers and certain other melons also contain citrulline but in lesser amounts.
Inside the body, L-citrulline is synthesized from both ornithine and glutamine, a process that occurs in the intestinal mucosa.
L-citrulline or its supplements travel through the liver without being changed.
But when it reaches the kidneys, it is converted to L-arginine and then released into the circulatory system.
Subsequently, L-arginine is converted to Nitric oxide, a conversion that occurs inside the inner linings (endothelium) of the blood vessels, as well as various other tissues and organs.
During this conversion process, L-citrulline is also created as a byproduct.
Uses of L-citrulline Supplements
Oral use of L-citrulline supplements can help to elevate nitric oxide availability in the body.
Nitric oxide helps circulatory vessels to relax and dilate, aiding the erectile tissue and smooth muscle tissues throughout the body.
By expanding in diameter, these vessels are able to deliver more blood and nutrients without increasing blood pressure.
This yields a positive effect on a circulation, nutrient delivery to muscles, sexual function, and more.
L-citrulline may also be used for the following health conditions:
- vascular disease,
- poor immune system functioning,
- cardiovascular disease,
- lysinuric protein intolerance,
- postoperative pulmonary hypertension and
- Certain other conditions and diseases.
In children, L-citrulline has been used intravenously to prevent pulmonary hypertension following heart surgeries.
Research suggests that an L-citrulline supplement can be helpful for decreasing blood pressure in those that are hypertensive.
In one double-blind human trial, healthy overweight middle-aged men were given 5600 mg of an L-citrulline supplement each day for 7 days.
After 7 days, data were collected and the result showed that blood flow was increased secondary to increased Nitric Oxide concentrations.
This improvement in blood flow was attributed to increased L-arginine levels, which was brought about by L-citrulline.
L-citrulline for Erectile Function and Circulation
Improving blood flow with L-citrulline supplement may help to alleviate certain symptoms of mild-to-moderate erectile problems.
While it is not as effective for erectile dysfunction as sildenafil (Viagra), research has shown that it acts similarly to the active molecule in Viagra, present a safer treatment option.
Animal research shows that L-citrulline supplements can help to prevent and treat certain blood vessel disorders.
For example, slow wound healing capacities in those with type 2 diabetes mellitus may be improved by regularly supplementing with L-citrulline.
How can you get L-citrulline in your diet?
Watermelon is one of the best food sources of L-citrulline, with legumes, meat, and nuts also containing the amino acid.
L-citrulline supplements are available over the counter, and one study from the British Journal of Nutrition found that doses between 2 and 15 grams (g) were safe and well-tolerated by the men in the study.
Supplements available in stores range from 500 milligrams (mg) to 1.5 g, and some supplements contain a mixture of L-citrulline and other ingredients.
Concerns and Side Effects
The NMCD reports no adverse effects associated with L-citrulline, but usage may affect the ways certain drugs are reacted and metabolized in the body.
Do not use in conjunction with nitrates for heart disease, or other medications like Viagra, Cialis, and Levitra that can alter blood pressure.
Pregnant and nursing women should avoid using L-citrulline supplements since there is not enough reliable research that has been completed to determine safety for these groups.
L-citrulline supplements are rated as “possibly safe” in healthy adults when properly and orally used.
In children, proper, oral usage is also rated as possibly safe, and 5.7 grams have been used daily for as long as 20 months with no side effects.
To be in a good position, it is best to talk to a doctor who knows about your health history and medications before starting supplementation with L-citrulline.