Vascularity And Pump
Also known as: L-Citrulline, Citrulline Malate, Nitric oxide boosters, Vasodilators, Pre-workout pump enhancers, L-citrulline
Overview
Supplements marketed for "vascularity and pump" typically contain ingredients that increase nitric oxide production or improve blood flow to muscles during exercise, with L-citrulline being a primary component. These supplements aim to enhance muscle blood flow, improve muscle "pump" (transient swelling), increase nutrient delivery, and potentially improve exercise performance and recovery. L-citrulline is a non-essential amino acid that is a precursor to L-arginine, which in turn is a precursor to nitric oxide (NO). NO induces vasodilation by relaxing vascular smooth muscle, improving blood flow and nutrient delivery to muscles. Common forms include L-citrulline and citrulline malate. Natural sources include watermelon and beetroot. Research suggests that L-citrulline supplementation reliably increases plasma L-arginine and nitric oxide metabolites, enhancing endothelial-dependent vasodilation at rest. However, effects on muscle pump during or after resistance exercise are inconsistent.
Benefits
L-citrulline supplementation reliably increases plasma L-arginine and nitric oxide metabolites, enhancing endothelial-dependent vasodilation at rest. For example, 8 g of citrulline malate has been shown to increase vasodilation 60 minutes post-ingestion. Some evidence suggests improved vascular tone and fluid shifts post-exercise with multi-ingredient blends containing L-citrulline. However, effects on muscle pump (muscle swelling) during or after resistance exercise are inconsistent; several studies found no significant increase in muscle thickness or blood flow parameters surrounding exercise bouts. Most studies focus on healthy adults, including strength athletes and resistance-trained individuals.
How it works
L-citrulline is converted to L-arginine, increasing substrate availability for endothelial nitric oxide synthase (eNOS). This enhances nitric oxide (NO) production. NO induces vasodilation by relaxing vascular smooth muscle, improving blood flow and nutrient delivery to muscles. L-citrulline is well absorbed orally and more effective than L-arginine at raising plasma L-arginine because it bypasses hepatic metabolism. The primary biological pathways involve the conversion of L-citrulline to L-arginine and the subsequent production of NO by eNOS.
Side effects
L-citrulline is generally safe and well-tolerated in doses up to 10-15 g. The most common side effect is mild gastrointestinal discomfort at higher doses. No significant adverse events have been reported in high-quality trials. L-citrulline may have potential additive effects with antihypertensives due to vasodilation, so caution is advised for individuals with low blood pressure or those on vasodilator medications. Limited data exists regarding safety in pregnant or lactating women, so use in these populations is not established. Overall, the safety profile is favorable with minimal reported side effects at recommended dosages.
Dosage
A minimum effective dose of around 3 g of L-citrulline may provide some vascular benefits, but 6-8 g doses more consistently increase vasodilation markers. Up to 15 g of L-citrulline has been shown to be safe in studies. For acute vasodilation effects, it is recommended to take L-citrulline 30-60 minutes before exercise. Citrulline malate is commonly used for the combined benefits of citrulline and malate. Citrulline has better bioavailability than arginine. No specific cofactors are required for its effectiveness.
FAQs
Does it improve muscle pump during workouts?
Evidence is mixed. While vasodilation at rest is improved, enhancement of muscle pump during resistance exercise is not consistently demonstrated.
Is it safe for daily use?
Yes, L-citrulline is generally safe at recommended doses.
When should it be taken?
L-citrulline should be taken about 30-60 minutes before exercise.
Will it improve strength or endurance?
Some studies suggest minor improvements in muscular endurance, but the effects are modest.
Are multi-ingredient blends better?
Some blends may have additional vascular benefits beyond citrulline alone.
Research Sources
- https://pubmed.ncbi.nlm.nih.gov/34511143/ – This systematic review and meta-analysis summarized the effects of whey protein on vascular reactivity and arterial stiffness. It showed some positive vascular effects, highlighting the importance of vascular function in exercise performance, although not directly related to pump supplements.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC9921013/ – This review examined L-citrulline and citrulline malate supplementation, finding consistent increases in plasma NO markers and vasodilation at rest but limited evidence for enhanced blood flow or muscle pump during resistance exercise. The review concluded that acute vasodilation is reliably increased, but exercise-related blood flow benefits are less clear.
- https://www.mdpi.com/2308-3425/12/4/112 – This randomized, single-blind crossover study compared a multi-ingredient supplement containing 3 g L-citrulline to 8 g citrulline alone. Both increased post-exercise muscle girth similarly, but the multi-ingredient supplement uniquely improved post-exercise vascular tone and fluid shifts and lowered blood pressure significantly, suggesting potential additional vascular benefits beyond citrulline alone.
- https://www.journalofexerciseandnutrition.com/index.php/JEN/article/view/144 – This study provides evidence supporting the use of L-citrulline to improve vascular tone and fluid shifts post-exercise. It highlights the potential benefits of multi-ingredient blends containing L-citrulline for enhancing vascular function and reducing blood pressure after exercise.
- https://academic.oup.com/ejcts/article/33/6/961/508151 – This article discusses the importance of nitric oxide in vasodilation and its role in cardiovascular health. It provides a broader context for understanding how L-citrulline, as a nitric oxide precursor, can influence vascular function.