Citrulline and Arginine: Is This a Good Supplement Combo?

Citrulline and arginine are two amino acids that have gained attention for their potential to enhance athletic performance.

Both are known to play essential roles in nitric oxide (NO) production, which can lead to improved blood flow, endurance, and recovery.

Citrulline is converted into arginine in the body, which then boosts NO production, improving vascular function and oxygen delivery to muscles.

• Citrulline and arginine are often sourced from watermelon, particularly from its rind, because watermelon is one of the richest natural sources of citrulline.
• Watermelon-based production is favored due to its high citrulline content, and supplement manufacturers extract citrulline from the fruit because it is more easily absorbed than directly consuming arginine.

By supplementing with citrulline, the body can produce more arginine over time, allowing for sustained nitric oxide production without the digestive issues sometimes associated with direct arginine intake.

But the real question is whether combining citrulline and arginine creates a synergistic effect, enhancing performance more than taking either one alone.

In this article, we will explore the mechanisms behind these amino acids and whether they are an effective combination for athletes looking to improve their performance.

Last update on 2025-03-27 / This article includes affiliate links/Images via Amazon Product Advertising API. I may earn commissions on purchases made through these links.

Understanding Citrulline and Arginine

Both citrulline and arginine are non-essential amino acids, meaning the body can produce them on its own.

However, supplementing with these amino acids has been shown to offer potential performance benefits, especially related to nitric oxide production and improved blood flow.

Citrulline

Citrulline is found naturally in foods like watermelon and is a precursor to arginine in the body. Once consumed, citrulline is converted to arginine, which then produces nitric oxide.

Citrulline bypasses the liver, allowing for a more efficient increase in arginine levels compared to direct arginine supplementation (Gonzalez & Trexler, 2020).

Arginine

Arginine, commonly found in meat, dairy, and fish, is an amino acid that plays a key role in producing nitric oxide through the nitric oxide synthase (NOS) pathway. Nitric oxide is crucial for vasodilation, helping to increase blood flow and oxygen delivery to muscles during exercise.

While arginine can be supplemented directly, it is subject to extensive breakdown in the liver, which reduces its overall effectiveness compared to citrulline (Bahri et al., 2008).

How Does the Combination Work?

The theory behind combining citrulline and arginine is that the two amino acids together may increase nitric oxide production more effectively than either one alone.

Since citrulline is converted into arginine, supplementing with both could potentially maximize arginine availability in the body, leading to greater nitric oxide production, enhanced vasodilation, and improved exercise performance.

Nitric Oxide Production

Nitric oxide is a molecule that helps widen blood vessels, improving circulation and delivering more oxygen and nutrients to muscles. This is particularly important during exercise, as enhanced blood flow can reduce fatigue, improve muscle endurance, and aid in faster recovery.

Studies show that citrulline is more efficient than arginine at increasing nitric oxide production because it is better absorbed and converted into arginine in the kidneys, bypassing the liver’s breakdown of arginine (Bailey et al., 2015).

When used together, the combination of citrulline and arginine may provide a more sustained increase in nitric oxide levels.

Enhanced Blood Flow and Vasodilation

The most widely studied benefit of citrulline and arginine supplementation is their ability to enhance blood flow through nitric oxide production. This improved circulation can increase oxygen and nutrient delivery to working muscles, which may help athletes perform at higher intensities for longer periods.

A study by Sureda and Pons (2012) suggested that supplementing with citrulline and arginine together could amplify nitric oxide production, improving aerobic capacity and exercise efficiency.

Performance Benefits of Citrulline and Arginine

The research on citrulline and arginine suggests that combining the two amino acids can offer several performance benefits, particularly in high-intensity or resistance-based exercise. Here are some key findings:

Reduced Fatigue and Improved Endurance

Citrulline and arginine may also help buffer ammonia and lactate buildup in muscles, which is associated with fatigue during high-intensity exercise. Ammonia is a byproduct of protein metabolism that can impair muscle function, while lactate buildup leads to muscle soreness and fatigue.

Citrulline, particularly when combined with malate (citrulline malate), plays a role in the urea cycle, helping to remove excess ammonia and improve endurance during exercise (Breuillard et al., 2015).

Improved Strength and Power

Several studies have indicated that citrulline and arginine supplementation can enhance power output and strength during resistance training.

For example, Gonzalez & Trexler (2020) reviewed the effects of citrulline supplementation on strength performance and found improvements in both upper and lower body exercises.

The combination of citrulline and arginine could potentially enhance these effects by boosting nitric oxide levels and increasing blood flow to the muscles, helping athletes push harder during weightlifting and other power-based exercises.

Reduced Muscle Soreness and Faster Recovery

Citrulline malate, in particular, has been shown to reduce muscle soreness after high-intensity exercise, likely due to its role in removing ammonia and other waste products.

When combined with arginine, this effect may be amplified, allowing for faster recovery and less downtime between workouts.

Bendahan et al. (2002) found that citrulline malate supplementation significantly reduced post-exercise muscle soreness and fatigue, which could help athletes recover quicker and return to training faster.

Side-Effects of Citrulline and Arginine Supplements

While there is promising research supporting the benefits of citrulline and arginine supplementation, there are also some considerations to keep in mind.

Bioavailability Issues

One of the challenges with arginine supplementation is its limited bioavailability due to extensive breakdown in the liver. Even though arginine is effective in producing nitric oxide, much of it is metabolized before it can be used by the body.

Citrulline, however, is more readily absorbed and converted into arginine, making it a more efficient option.

Some research suggests that supplementing with citrulline alone may be just as effective, if not more so, than combining it with arginine due to this bioavailability issue (Bahri et al., 2008).

Potential Gastrointestinal Discomfort

High doses of arginine can cause gastrointestinal distress in some individuals, leading to discomfort or bloating. Citrulline, on the other hand, is typically better tolerated and may be a more comfortable option for athletes.

If you experience digestive issues with arginine, opting for a citrulline-only supplement could still provide many of the same performance benefits.

Best Arginine and Citrulline Supplement

There are a lot of good arginine and citrulline supplements on the market, respectively, and there are quite a few good combination supplements as well.

One of the best arginine plus citrulline supplements on the market is the Horbäach L-Arginine L-Citrulline Complex. This supplement combines 3,000 mg of L-arginine and L-citrulline in a convenient capsule form, offering an effective way to boost nitric oxide (NO) production for improved blood flow and athletic performance.

What sets this product apart is its potent formula, featuring free-form amino acids that are easily absorbed and quickly released into the bloodstream.

This ensures a steady increase in NO levels, helping to dilate blood vessels, enhance nutrient delivery, and reduce muscle fatigue during workouts.

The Horbäach L-Arginine L-Citrulline Complex is also free from artificial flavors, gluten, and other unnecessary additives, making it a clean and reliable choice for athletes. Whether you’re engaging in high-intensity workouts or endurance training, this supplement offers excellent support for muscle recovery and energy production.

For those seeking a trusted, non-GMO, and gluten-free nitric oxide booster, this product is highly recommended, particularly due to its affordability, purity, and high-quality ingredients.

Last update on 2025-03-27 / This article includes affiliate links/Images via Amazon Product Advertising API. I may earn commissions on purchases made through these links.

Final Thoughts: Is Citrulline and Arginine a Powerful Combination?

The combination of citrulline and arginine shows potential as an effective strategy for improving performance, particularly in activities requiring strength, power, and recovery.

By boosting nitric oxide production, enhancing blood flow, and reducing muscle fatigue, this amino acid duo may help athletes push harder and recover faster from intense workouts.

However, due to the bioavailability challenges of arginine, some athletes may benefit just as much, if not more, from citrulline supplementation alone.

Citrulline’s superior absorption and conversion to arginine make it a reliable option for boosting nitric oxide levels without the gastrointestinal discomfort that sometimes comes with arginine.

Ultimately, the decision to use citrulline, arginine, or a combination of both depends on individual goals, training intensity, and how well the body tolerates each supplement.

Athletes looking to improve blood flow, reduce fatigue, and enhance performance may find that this combination is a powerful addition to their supplement regimen.