L-Citrulline is a widely recognized pre-workout supplement used by athletes and fitness enthusiasts seeking to enhance their training capacity. This non-protein amino acid improves blood flow and delays muscle fatigue, making it a common ingredient in performance formulas. Understanding the correct dosage is important for maximizing benefits. The amount you should take before a workout depends directly on the specific form of the supplement chosen.
The Performance Rationale for Citrulline
Athletes take citrulline pre-workout to capitalize on its role in the body’s Nitric Oxide (NO) pathway. Once ingested, citrulline is efficiently converted by the kidneys into L-arginine, the direct precursor to NO. This conversion is more effective than supplementing with L-arginine directly, as L-arginine is largely broken down in the digestive system.
The resulting increase in Nitric Oxide acts as a potent vasodilator, signaling the smooth muscles surrounding blood vessels to relax. This vasodilation widens the blood vessels, which improves the delivery of oxygen and nutrients to active muscles during exercise. Better blood flow supports increased energy production and the faster removal of metabolic waste products like ammonia, which contributes to muscle fatigue. This mechanism translates to delayed exhaustion, allowing for more repetitions and greater overall power output.
Establishing the Effective Dosage Range
The clinically effective dose centers on the amount of pure L-Citrulline delivered. Research suggests that a minimum intake of 6 to 8 grams of pure L-Citrulline is required to achieve performance benefits before a workout. Dosages below this range may offer circulatory benefits, but they are unlikely to maximize effects on power output and endurance.
Taking a dose within this range is associated with better muscle oxygenation and a reduction in perceived effort during high-intensity exercise. Exceeding the 8-gram threshold for a single serving rarely provides additional performance gains. Furthermore, excessively high doses increase the risk of gastrointestinal (GI) discomfort, such as bloating or stomach upset. For best results, the goal is to consistently hit the 6 to 8-gram mark of the active compound.
The Critical Difference Between Citrulline Forms
Citrulline is most commonly sold in two distinct forms, which significantly impacts the total powder weight required for an effective dose. The first is pure L-Citrulline, which is 100% active amino acid, meaning 6 grams of powder contains 6 grams of L-Citrulline. The second and more common form is Citrulline Malate (CM), where L-Citrulline is bonded with malic acid.
Citrulline Malate is typically sold in a 2:1 ratio, meaning two parts L-Citrulline are combined with one part malic acid. To calculate the required dose of Citrulline Malate, you must account for the malic acid portion, which makes up about one-third of the total weight. Therefore, to achieve the clinically relevant 6 grams of pure L-Citrulline, a user must consume a total of approximately 9 grams of 2:1 Citrulline Malate powder.
Timing, Cycling, and Safety Considerations
For acute performance effects, the timing of citrulline intake relative to the exercise session is important. Peak plasma levels of L-arginine, responsible for increased Nitric Oxide production, are typically reached 60 to 90 minutes after ingestion. Consequently, consuming the dose one to one-and-a-half hours before the workout is recommended to ensure the compound is fully active during training.
While many people use citrulline pre-workout, consistent daily dosing may be more beneficial for maintaining elevated Nitric Oxide levels. This approach is helpful during periods of high-volume training or for those seeking broader cardiovascular health benefits. L-Citrulline is generally well-tolerated, but the most common side effect at high doses is mild GI distress. Individuals with pre-existing medical conditions, particularly those on blood pressure medications, should consult a healthcare professional before beginning supplementation.