Meanwhile, nitric oxide-boosting supplements have skyrocketed in the fitness and performance nutrition world. These chemicals help to increase the blood flow and increase oxygen delivery to your muscles, which can also help with quicker recovery. L-citrulline and L-arginine are two of the most common used amino acids for this exact application. However, between L-citrulline vs L-arginine for increased endurance, which supplement is better?

Now, we unpack their contrasts, the possible potential for performance benefit and what the science says, how you can utilise each of these to help maximise your goals.

What Are L-Arginine and L-Citrulline?

L-arginine is a conditionally essential amino acid that serves as an endogenous donor for NO production. This dilates blood vessels, leading to improved circulation and oxygen and nutrient delivery to your workout muscles. Food sources containing arginine are poultry, fish, dairy products, and red meat and soy naturally.

In contrast, L-citrulline is a non-essential amino acid found in watermelons, squash, cucumbers. Upon consumption, your body turns L-citrulline into L-arginine in the kidneys and this make it to support nitric oxide production. Studies have also found that l-citrulline is more effective in raising blood arginine levels than arginine supplements directly.

How Do They Work in the Body?

L-arginine and L-citrulline provide the basic material for urea cycle and nitric oxide production in different pathways to achieve the same purpose respectively.

ARG is a substrate of nitric oxide synthase (NOS), acting as the direct precursor of NO and leading to vasodilation.

L-citrulline does not pass through the intestines, and it becomes arginine in the kidneys leading to a much more reliable & longer NO boosting effect.

This bioavailability advantage is one of the reasons L-Citrulline is chosen over alternative endurance enhancers.

Well, before we get into the science of it all its important that you understand why people take L-Citrulline or L-Arginine (over each other) for their endurance.

As far as endurance is concerned, it has a clear winner: L-citrulline always leaves behind L-arginine.

Clinical studies highlight the difference:

In fact, a 2010 studyPublished in the Journal of Strength and Conditioning Research found that L-citrullineIncreased cycling efficiency by delaying fatigue and increasing adenosine triphosphate.

One 2006 study(13) demonstrated that L-arginine had little effect on nitric oxide levels because gut absorption was poor.

A different trial in the British Journal of Clinical Pharmacology found that L-citrulline was a better way to increase plasma arginine than simply using L-arginine itself.

It is considered by many experts to be the best choice for long-distance, high-intensity athletes.

L-Arginine Benefits for Males

In spite of not being the best for long-term stamina, L-Arginine actually has some great advantages for men such as :

• Enhanced erectile function through higher blood flow
• Boosts sperm quality and Motility
• Improvement in blood flow and dilation of vessels (Cardivascular support)
• Acute transient muscle pumps desired during workouts

Still, there are some downsides to L-arginine you might want to know about. Any Amount >6g – Some Notice:

• Digestive distress, frequent gas, bloating and possible diarrhea
• Potential blood pressure drops, especially when used with vasodilators
• Worsening of asthma
• Interactions with medications such as nitrates or ED drugs
• For these reasons, people may take less L-arginine or cycle it on and off.

Field Testing: Popular Among Athletes and Coaches

Many performance coaches suggest looking for citrulline in the form of L-citrulline malate, which comes with additional help from malic acid (a key player in energy metabolism). This version is popular for its dual benefit (increased nitric oxide production and decreased fatigue) in the endurance and strength circles.

Although some pre-workout products offer both amino acids, many seasoned athletes find 5–8g of citrulline malate without arginine is enough to provide muscular endurance, pump, and recovery.

Let's say a triathlete prepares to run two marathons consecutively. Previously she struggled with muscle soreness and fatigue much earlier in classes before taking supplements. Once i started dosing 6g L citrulline malate daily, the improvements were obvious; increased endurance, faster recovery time, and more consistent trainies.

I had been experimenting with L-arginine which gave me a small pump but did not give me the sustained energy that would help during endurance sports.

L-Citrulline + L-Arginine: Okay to Take Together?

Yes — L-citrulline and L-arginine work well in tandem with each other to create a synergy effect:

• L-arginineFast Nitric Oxide Spike
• L-CITRULLINE: SMOOTH, COLORLESS LONG-LASTING BOOST

This is found in many performance formulas to be used preworkout or for athletes that want both immediate and sustained improvements in exercise.

Does L-Arginine Increase Endurance?

It's true that L-arginine can increase seminal volume, but only if used for a limited time before exercise. The problem — the effect of carbohydrate inbested this way is not sustained enough to last long distance, longer than an hour energy expenditures. It could still be worthwhile for sprinters or in sports that require short, explosive work.

Does L-Citrulline Increase Endurance?

Yes—L-citrulline excels in endurance performance. It:

• Increased Oxygen and Nutrient Delivery to Muscles.
• Flushes ammonia and lactic acid
• Decreases muscle soreness after a workout
• It is commonly known as the best nitric oxide supplement for serious athletes.

Dosage and Timing Recommendations

L-citrulline:

• 6-8g citrulline malate or 3-5g pure L-citrulline
• Consume 30–60 minutes pre-workout.

L-arginine:

• A wrapped on an 3–6g empty belly
• Consume 15–30 minutes before exercise
• Only if stacking, and then reduce dosage of each and test before increasing.

Stacking with Other Supplements

Exercise should include a combination of max-strength exercises, intervals, and metabolic workouts for best results. 3 your workout needs to consist of high-strength exercises (very basic motions) which ought to be done at excessive intensity….

• Beta Alanine- it reduces the muscle fatigue
• Creatine – supports high-intensity effort
• Electrolytes — reduces cramping and hydration
• Beetroot powder -- A PB, of course!

Watch out for Your Overlapping Ingredients in Your Pre-Workout Shelllivet

Long-Term Use and Cycling

Although they can both be taken daily, some people prefer cycling:

• 8 to 12 weeks on, then 2–4 weeks off
• Ensures the form sensitivity and performance gains.

Final Thoughts

While both citrulline and arginine serve a role in the supplement wars, L-citrulline wins when it comes to support during endurance activities (and any other exercise that doesn't have you reaching your max all-out effort). It gives a longer lasting nitric oxide improvement, delays fatigue and recovery from intensive workouts.

L-arginine, on the other hand, is really specific for male well being and brief lived vascular assistance. The right approach for you will depend on your specific goals, whether that means getting faster in your next race or recovering more effectively post-workout, or anything specifically pertaining to your vascular health.

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