Citrulline
L-Citrulline is an amino acid. It is turned into L-arginine in the kidneys after supplementation, which means L-citrulline supplementation is a more effective method of increasing L-arginine levels in the body than L-arginine supplementation.
arginine. Citrulline is very readily converted to arginine as needed, and it is also better absorbed than arginine, which not only makes it a better source of arginine for the body but can mean a lower rate of gastrointestinal upset than arginine when taken in high doses.
What is citrulline malate?
Citrulline bound to malate, an organic salt of malic acid, an intermediate in the citric acid cycle. It is the most researched form of citrulline, and there is speculation about an independent role of malate in producing performance benefits, but there’s insufficient research to compare citrulline malate to L-citrulline directly. Citrulline malate can be taken in the dose used in studies, but it’s important to keep in mind that 1.76 g of citrulline malate is needed to about 1 g of citrulline.
How to Take Citrulline
Recommended dosage, active amounts, other details
To supplement L-citrulline for circulatory health or to alleviate erectile dysfunction, take 1,000 mg of citrulline, three times a day with meals, for a total daily dose of 3,000 mg. L-citrulline does not need to be taken with meals, however.
To supplement for circulatory health with a citrulline malate supplement, take 1.76 g of citrulline malate for every 1 gram of citrulline you would normally take.
To supplement L-citrulline to enhance sports performance, take 6,000 – 8,000 mg of citrulline malate about an hour before exercise.
Human Effect Matrix
The Human Effect Matrix looks at human studies (it excludes animal and in vitro studies) to tell you what effects citrulline has on your body, and how strong these effects are.
| GRADE | LEVEL OF EVIDENCE[show legend] | |||||
| LEVEL OF EVIDENCE
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OUTCOME | MAGNITUDE OF EFFECT
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CONSISTENCY OF RESEARCH RESULTS
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NOTES | ||
| Blood Glucose | – | Very HighSee all 3 studies | There do not appear to be any significant influences of supplemental citrulline on blood glucose concentrations | |||
| Insulin | – | HighSee all 4 studies | Most studies note that there is no significant change in insulin concentrations, although a lone study (not replicated) suggested that the exercise-induced increase in insulin was suppressed with cit…
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| Fatigue | Notable | ModerateSee all 3 studies | The decrease in fatigue during exercise is thought to underlie most of the benefit seen with training capacity (work volume), although in men who self-report fatigue issues supplemental citrulline ap…
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| Muscle Soreness | Notable | –See study | The lone study using citrulline acutely pre-workout noted a 40% reduction in muscle soreness the following two days after the workout. | |||
| Nitric Oxide | Notable | Very HighSee 2 studies | Nitric oxide derivatives (nitrate and urinary cGMP, since nitric oxide itself is hard to measure these biomarkers are indicative of nitric oxide production) appear to be reliably increased following …
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| Plasma Arginine | Notable | Very HighSee 2 studies | Citrulline can increase plasma arginine concentrations, and due to acting as a resevoir of arginine it is actually more effective overall at increasing plasma arginine than arginine itself (acute pea…
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| Training Volume | Notable | –See study | The increase in work capacity seen with citrulline supplementation appears to be time dependent. While there are no inherent and immediate effect, the reduction of fatigue later in a weight lifting w…
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| Blood Flow | Minor | –See study | An increase in blood flow is noted with citrulline supplementation in persons with impaired blood flow | |||
| Blood Pressure | Minor | ModerateSee all 3 studies | A decrease in blood pressure is noted secondary to increasing plasma arginine (and thus increasing nitric oxide), but this blood pressure reduction may only occur in those with hypertension or prehypertension | |||
| Creatinine | Minor | –See study | A slight increase in creatinine has been noted with citrulline supplementation, practical relevance unknown. | |||
| Growth Hormone | Minor | Very HighSee 2 studies | An increase in growth hormone has been noted with exercise, but not at rest. Practical significance of this information is unknown, since Arginine supplementation has unreliable effects itself | |||
| Immunity | Minor | –See study | Neutrophil oxidative burst post-workout appears to be enhanced when the exercise is preloaded with citrulline supplementation | |||
| Plasma Glutamine | Minor | ModerateSee 2 studies | Although acute usage does not appear to influence plasma glutamine, a week of high dose supplementation (0.18g/kg) has been noted to reduce glutamine concentrations slightly. | |||
| Plasma Nitrate | Minor | –See study | An increase in plasma nitrate has been noted with citrulline supplementation, but not to the degree of supplemental nitrate itself | |||
| Urea | Minor | –See study | An increase in urea is seen with citrulline supplementation (possibly due to increased serum ornithine sequestering ammonia) | |||
| Aerobic Exercise | – | –See study | No significant influence on a treadmill test to exhaustion nor oxygen kinetics during this test | |||
| C-Reactive Protein | – | –See study | No significant influence on C-reactive protein concentrations | |||
| DNA Damage | – | –See study | No significant influence of citrulline on DNA damage | |||
| HDL-C | – | –See study | No significant influence on HDL-C concentrations | |||
| Heart Rate | – | ModerateSee 2 studies | No significant influence on heart rate seems likely, although at least one study noted a random but significant reduction post-exercise | |||
| IGF-1 | – | –See study | No demonstrated effects on IGF-1 concentrations following the usage of citrulline supplementation | |||
| LDL-C | – | –See study | No significant influence on LDL-C concentrations in serum following citrulline supplementation | |||
| Lactate Production | – | –See study | No significant influence on lactate production seen with citrulline supplementation before exercise | |||
| Lipid Peroxidation | – | –See study | No significant influence of citrulline on lipid peroxidation has been noted | |||
| Liver Enzymes | – | –See study | Plasma concentrations of LDH are unaffected following citrulline supplementation | |||
| Muscle Protein Synthesis | – | –See study | Currently no human evidence to support a practically significant increase in muscle protein synthesis at rest with citrulline supplementation | |||
| Total Cholesterol | – | –See study | No significant influence on total cholesterol concentrations | |||
| Erections | Minor | –See study | Hardness of erections in persons with mild erectile dysfunction appears to be increased following supplementation of citrulline supplementation. | |||
| Exercise Capacity (with Heart Conditions) | Minor | –See study | Citrulline has been noted to increase physical exercise capacity in persons with heart failure. | |||
| Muscle Oxygenation | Minor | –See study | An increase in muscle ATP production via aerobic means was noted in men given 6g citrulline daily, but this appeared to be attenuated with time. | |||
| Right Ventricular Ejection Fraction | Minor | –See study | In persons with heart failure with normal ejection fractions, right ventricular ejection fraction during exercise appears to be increased relative to control. | |||
Things To Know & Note
Is a Form Of
• Performance Enhancer
• Amino Acid Supplement
Other Functions:
• Cardiovascular
Primary Function:
• Muscle Gain and Exercise