What is Citrulline Malate?
Citrulline malate is a dietary supplement that combines L-citrulline, a semi-essential amino acid, with malic acid (malate), an organic acid involved in cellular energy production. L-citrulline is naturally produced in the body and plays a crucial role in the urea cycle, which helps eliminate ammonia from the body. The compound is named after the Latin word “citrullus,” referring to watermelon, where it was first discovered in significant quantities.
Unlike essential amino acids that must be obtained through diet, citrulline can be synthesized by the body, though supplementation may provide additional benefits. When combined with malate, citrulline’s bioavailability and potential therapeutic effects may be enhanced. This combination supplement has gained popularity particularly among athletes and fitness enthusiasts for its potential performance-enhancing properties.
Health benefits & uses
Exercise Performance (Moderate Evidence): Research suggests citrulline malate may improve exercise performance, particularly in resistance training. Studies have shown it can increase the number of repetitions performed during weightlifting and reduce muscle soreness following intense exercise.
Cardiovascular Health (Moderate Evidence): Citrulline supplementation may support cardiovascular health by increasing nitric oxide production, which can improve blood flow and potentially reduce blood pressure in individuals with elevated levels.
Muscle Recovery (Limited Evidence): Some studies indicate citrulline malate may reduce delayed onset muscle soreness (DOMS) and accelerate recovery between training sessions, though more research is needed to establish definitive benefits.
Erectile Dysfunction (Limited Evidence): Due to its role in nitric oxide production, citrulline has been investigated as a potential treatment for mild erectile dysfunction, with some preliminary positive results reported in small studies.
How it works
Citrulline malate works through several interconnected mechanisms. When consumed, L-citrulline is converted to L-arginine in the kidneys, which then serves as a substrate for nitric oxide synthase enzymes. This process produces nitric oxide, a potent vasodilator that relaxes blood vessels and improves circulation.
The malate component contributes to the Krebs cycle (citric acid cycle), supporting cellular energy production and potentially reducing the accumulation of lactate during exercise. This dual action may explain why citrulline malate appears more effective than citrulline alone for exercise performance.
Additionally, citrulline plays a role in the urea cycle, helping to remove toxic ammonia produced during protein metabolism. This function may contribute to reduced fatigue during prolonged exercise and improved recovery.
Dosage
There is no established Recommended Daily Allowance (RDA) or Upper Limit (UL) for citrulline malate, as it is not considered an essential nutrient. Typical adult dosages used in research and clinical practice include:
For exercise performance: 6-8 grams of citrulline malate taken 30-60 minutes before exercise
For cardiovascular support: 3-6 grams daily, often divided into multiple doses
General supplementation: 3-9 grams daily, depending on individual goals and tolerance
It is advisable to start with lower doses to assess tolerance and gradually increase as needed. Consultation with a healthcare provider is recommended before beginning supplementation, especially for individuals with existing health conditions or those taking medications.
Food sources
While citrulline occurs naturally in several foods, dietary sources typically provide much lower amounts than those used therapeutically in supplements:
Watermelon: The richest natural source, containing approximately 250mg of citrulline per cup of diced fruit
Other melons: Cantaloupe and honeydew contain smaller amounts
Cucumbers: Contain modest levels of citrulline
Pumpkin and other squashes: Provide small amounts
Legumes: Chickpeas and other legumes contain trace amounts
To achieve therapeutic doses equivalent to those used in research studies, supplementation is typically necessary, as it would be impractical to consume sufficient quantities through food sources alone.
Safety & side effects
Citrulline malate is generally well-tolerated by most individuals when used at recommended dosages. Reported side effects are typically mild and may include:
Gastrointestinal discomfort, including stomach upset or diarrhea, particularly with higher doses or when taken on an empty stomach. Some individuals may experience mild nausea or bloating initially.
Very high doses may potentially cause headaches or dizziness due to the vasodilatory effects of increased nitric oxide production. These effects are generally temporary and resolve with dose reduction.
Long-term safety data is limited, though short to medium-term use appears safe for healthy individuals. As with any supplement, discontinue use and consult a healthcare provider if adverse effects occur.
Interactions
Blood pressure medications: Citrulline malate may enhance the effects of antihypertensive drugs, potentially causing excessive blood pressure reduction. Monitor blood pressure closely if using both.
Nitrates and PDE5 inhibitors: Combining citrulline with medications like nitroglycerin or sildenafil may amplify vasodilatory effects.
L-arginine supplements: Since citrulline converts to arginine, concurrent use may increase arginine levels more than intended.
Caffeine: Often combined in pre-workout supplements, though no significant negative interactions have been reported.
Who should be cautious
Individuals with low blood pressure (hypotension) should exercise caution, as citrulline malate may further reduce blood pressure. Those with cardiovascular disease should consult their healthcare provider before use, particularly if taking heart medications.
People with kidney disease should be cautious, as citrulline metabolism occurs primarily in the kidneys. Pregnant and breastfeeding women should avoid supplementation due to insufficient safety data.
Individuals scheduled for surgery should discontinue use at least two weeks beforehand due to potential effects on blood pressure and circulation.
Frequently asked questions
When is the best time to take citrulline malate?
For exercise performance, take 30-60 minutes before workouts on an empty stomach for optimal absorption. For general health benefits, timing is less critical, though dividing daily doses may improve tolerance.
How long does it take to see results?
Acute effects on exercise performance may be noticed within hours of supplementation. Cardiovascular benefits typically develop over several weeks of consistent use. Individual responses vary significantly.
Can I take citrulline malate every day?
Daily supplementation appears safe for most healthy adults based on available research. However, some people prefer cycling on and off supplements or using them only on training days.
Is citrulline malate better than L-arginine?
Research suggests citrulline may be more effective than arginine for raising blood arginine levels, as it bypasses first-pass metabolism in the liver and is more readily absorbed.
Should I take citrulline malate with food?
Taking on an empty stomach may improve absorption and reduce the time to peak blood levels. However, if gastrointestinal upset occurs, taking with a small amount of food may help while still providing benefits.
Classification:
Typical dose: — · Studied up to: —
References
Authoritative profile & live regulatory status: Citrulline Malate on SupplementIndex →