L-Arginine & L-Citrulline: Unleashing Synergistic Power for Athletes and Bodybuilders

L-Citrulline combined with L-Arginine


The supplementation landscape continuously evolves in athletic performance and bodybuilding, driven by scientific research and breakthroughs.

In this context, two compounds, L-arginine and L-citrulline, have drawn significant attention for their potential benefits.

This article will explore these amino acids, their advantages, and their possible synergistic amplification of by their combination.

Understanding L-Arginine and L-Citrulline

L-Arginine and L-Citrulline are naturally occurring amino acids crucial in various metabolic processes. L-arginine, a semi-essential amino acid, primarily functions in protein synthesis and is a precursor to nitric oxide (NO), a potent vasodilator.

On the other hand, L-citrulline, a non-essential amino acid, contributes to NO production but has a less direct route. It converts to L-arginine in the kidneys before being used for NO production.

Benefits of L-Arginine

L-arginine’s contribution to nitric oxide production is its most significant benefit for athletes and bodybuilders. Nitric oxide acts as a vasodilator, expanding the blood vessels, improving blood flow, and consequently, oxygen and nutrient delivery to the muscles.

This process enhances performance, allowing athletes to train longer and harder, and supports faster recovery post-workout. Additionally, L-arginine helps to stimulate the release of growth hormone, promoting muscle growth and recovery.

However, L-arginine is not absorbed particularly well because it is susceptible to rapid degradation by enzymes in the intestine and liver.

Benefits of L-Citrulline

Though indirect, L-Citrulline’s contribution to nitric oxide production offers several advantages. Its conversion to L-arginine provides a sustained increase in plasma L-arginine levels and NO production. Like L-arginine, L-citrulline promotes blood flow, aiding in nutrient delivery and waste removal from the muscles.

Additionally, L-citrulline may reduce muscle soreness and improve endurance, making it a popular choice for endurance athletes.

Amazingly, L-citrulline is actually more effective for boosting nitric oxide than L-arginine because it bypasses the liver’s metabolism, allowing for greater systemic availability and conversion to L-arginine, which is the precursor of nitric oxide.

The Power of Combination

When combined, L-arginine and L-citrulline offer several synergistic benefits. The L-citrulline to L-arginine pathway provides a sustained source of L-arginine, promoting prolonged nitric oxide production, while direct L-arginine supplementation offers an immediate boost. This dual-action approach enhances the overall effectiveness of both supplements.

Further, by spreading the nitric oxide production over time, the combination reduces the likelihood of experiencing side effects related to high-dose L-arginine supplementation, such as gastrointestinal discomfort.

Moreover, L-citrulline might enhance L-arginine absorption, creating a more efficient pathway for nitric oxide production. It’s a one-two punch that can support increased endurance, improved muscle recovery, and more effective nutrient delivery to the muscles during strenuous activities.

2017 study by Suzuki, et al, shows a significant boost in plasma L-Arginine occurs when combined with L-Citrulline vs just L-Cit or L-Arg alone
As you can see in this 2017 study by Suzuki, et al, a significant boost in plasma L-Arginine occurs when combined with L-Citrulline vs just L-Cit or L-Arg alone.

Implications for Athletes and Bodybuilders

For athletes and bodybuilders, combining L-arginine and L-citrulline has several potential benefits. Increased nitric oxide production may improve performance, promote muscle growth, and accelerate recovery. The sustained delivery of L-arginine through L-citrulline may also support longer, more intense training sessions.

While more research is needed to quantify these benefits fully, anecdotal evidence and preliminary studies suggest a positive impact on athletic performance and recovery.


Combining L-arginine and L-citrulline offers a compelling proposition for athletes and bodybuilders. Their potential to enhance nitric oxide production, improve blood flow, and support muscle growth and recovery make them a worthwhile addition to any performance-oriented supplement regimen.

While the existing body of research is promising, it’s crucial to remember that supplementation should be part of a broader performance strategy, including a balanced diet, regular exercise, and adequate rest. Individuals should consult with a healthcare professional before beginning any new supplementation regime.

Overall, science heavily suggests L-arginine and L-citrulline, in their unique yet complementary roles, hold significant potential as allies in pursuing athletic excellence and optimal bodybuilding results.


  1. The Physiological Effects of Amino Acids Arginine and Citrulline: Is There a Basis for Development of a Beverage to Promote Endurance Performance? A Narrative Review of Orally Administered Supplements by S Nyawose, R Naidoo, N Naumovski, and AJ McKune. Link
  2. l-Citrulline supplementation improves O2 uptake kinetics and high-intensity exercise performance in humans by B Bailey, J Blackwell, J Lord, and P Vanhatalo. Link
  3. Dietary Arginine and Citrulline Supplements for Health and Exercise: A Comprehensive Review of Clinical Trials by AJ McKune and S Semple. Link
  4. The Effects of Consuming Amino Acids L-Arginine, L-Citrulline (and Their Combination) as a Beverage or Powder, on Athletic and Physical Performance: A Systematic Review by S Nyawose, R Naidoo, N Naumovski, and AJ McKune. Link
  5. Effect of L-citrulline intake on intermittent short-time high-intensity exercise performance by T Suzuki, T Morita, and K Kobayashi. Link