L-Arginine vs L-Citrulline: Which Is Higher?

L-arginine and L-citrulline are amino acids that play important roles in your physique’s nitric oxide manufacturing.

Nitric oxide is a gasoline molecule that helps blood vessels chill out and dilate their vascular clean muscle cells, which improves blood move.

By enhancing blood circulation, L-arginine and L-citrulline will help alleviate signs of hypertension, improve sexual well being, and ease signs of diabetes.

However which one is best? Must you take each to see the consequences in your physique?

On this article, we are going to discover the arginine and citrulline fundamentals and the variations between L-arginine vs L-citrulline so you’ll be able to select which complement is best for you.

What’s L-arginine?

L-arginine is a necessary amino acid required for a lot of bodily features.

It’s present in varied meals sources, together with meats, fish, dairy, eggs, and sure greens. It’s additionally out there in complement type.

It’s a precursor of nitric oxide, a potent vasodilator, which is accountable for the regulation of blood move.

L-arginine is produced within the physique from the amino acid L-citrulline by the motion of assorted enzymes.

Then, nitric oxide synthesis makes use of L-arginine by the enzyme nitric oxide synthase.

As soon as synthesized and launched, nitric oxide has many necessary features within the physique, together with regulating blood strain, immune system perform, and cell signaling.

Thus, it’s no shock that L-arginine has been linked to improved cardiovascular health, muscle efficiency, and sexual perform. It has additionally been used to deal with kidney and liver problems.

RELATED: Does L-Arginine Help With Erectile Dysfunction?

What’s L-citrulline?

L-citrulline is an amino acid carefully associated to L-arginine. It’s discovered naturally in meals like watermelon, pumpkin seeds, and nuts and can be taken as a dietary complement.

The physique makes use of L-citrulline to supply L-arginine, which is then transformed into nitric oxide, a substance with the above features.

Athletes and bodybuilders primarily use this complement as a result of it could enhance muscle efficiency and endurance.

Moreover, L-citrulline might profit folks with heart problems, as it could assist improve blood flow and cut back irritation.

And even for those who’re not an athlete, the benefits of L-citrulline will help. One study checked out L-citrulline in older adults with blood circulation issues of their legs.

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The researchers reported that 14 days of L-citrulline had been sufficient to extend femoral blood move by 11%.

Furthermore, the muscle mass and blood vessels turned 14% extra attentive to decrease limb train in these sufferers.

RELATED: Erectile Dysfunction and L-Citrulline: What You Should Know.

L-arginine vs L-citrulline Comparability

On this part, we examine L-arginine vs L-citrulline and their makes use of, variations, similarities, and effectiveness.

Makes use of

As talked about above, each amino acids have a job within the synthesis of nitric oxide (NO) within the physique, which is important for blood move regulation, immune system functioning, and the regulation of the nervous system.

Nitric oxide is produced by the enzyme nitric oxide synthase (NOS) from L-arginine. Nonetheless, since L-citrulline can produce L-arginine, each enhance plasma nitric oxide ranges and have comparable makes use of. You’ll be able to say they undergo the identical pathway however from completely different standpoints.

L-arginine as a complement or nutrient is used to improve sexual health, enhance blood circulation, obtain higher management of blood strain ranges, boost the immune system, and defend the organism towards cardiovascular illnesses.

Citrulline malate has the identical purposes vs L-arginine, however athletes additionally use it to enhance their stamina and bodily efficiency.

And, as talked about above, even for those who’re not an athlete, your muscle mass can turn out to be extra attentive to train by growing their blood move.

In comparison with L-arginine, L-citrulline has higher proof in energy and conditioning analysis.

Regardless of being one step away from nitric oxide in comparison with L-arginine, L-citrulline is believed to stay untouched for longer, which extends the vary of makes use of we may give this complement.


L-arginine is a semi-essential amino acid, which means it may be made within the physique, however it must also be acquired from meals sources.

It’s the direct precursor for nitric oxide manufacturing, which means it’s the molecule that’s first utilized in synthesizing nitric oxide.

However, L-citrulline is a necessary amino acid, which means it needs to be obtained by meals or dietary supplementation. It isn’t synthesized in any approach by the organism.

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As an alternative of directly producing nitric oxide, L-citrulline is the first molecule used to synthesize L-arginine, which then maintains your nitric oxide ranges.

Research have discovered that L-citrulline is more practical at increasing nitric oxide ranges within the physique than L-arginine, making it a extra fascinating possibility for these trying to enhance blood move and coronary heart well being.

Moreover, due to its distinctive metabolic pathway, L-citrulline has been proven to be more practical than L-arginine in reducing fatigue, muscle soreness, and post-exercise restoration time.


As famous above, each of those amino acids are necessary for the manufacturing of nitric oxide.

Nonetheless, they strategy this in numerous methods. L-arginine is the direct precursor of nitric oxide, whereas L-citrulline is not directly concerned within the course of.

L-arginine and L-citrulline are each amino acids and really comparable of their chemical construction and plenty of different respects.

Each are present in meals corresponding to fish, dairy, eggs, and plenty of dietary supplements. So, you might select a base weight-reduction plan with arginine content material or search for a complement.

Each are used as dietary dietary supplements to assist with circulation, and heart health, amongst different purposes.

When it comes to well being advantages, each L-arginine and L-citrulline have been proven to have helpful results on blood move.

Though L-arginine is extra generally used for these purposes, L-citrulline can be utilized in its place.


Research have proven that supplementing with L-arginine can enhance NO manufacturing and enhance blood move, however the results are short-lived, and the absorption of L-arginine shouldn’t be very environment friendly.

Thus, it doesn’t attain very excessive plasma amino acid focus. This might enhance by giving increased doses of L-arginine, however such excessive doses might trigger gastrointestinal misery.

Conversely, supplementing with L-citrulline can enhance NO manufacturing and enhance blood move extra successfully than L-arginine.

Moreover, L-citrulline is best absorbed than L-arginine and doesn’t trigger gastrointestinal misery.

Subsequently, L-citrulline is mostly thought of a more practical complement for growing NO manufacturing and enhancing cardiovascular well being than L-arginine.

Additionally, L-citrulline shouldn’t be damaged down by the physique like L-arginine is. That’s why it’s thought to have higher bioavailability than L-arginine, which means that it’s extra prone to be absorbed and utilized by the physique.

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How lengthy do they take to work?

After taking both L-arginine or L-citrulline, it solely takes a couple of minutes or as much as one hour earlier than the dietary supplements or vitamins in meals are absorbed and used within the organism.

However the caveat of arginine or citrulline supplementation is that it takes longer to provide noticeable outcomes.

Nitric oxide manufacturing begins the identical day you are taking the primary tablet. Nonetheless, the consequences of L-arginine and L-citrulline aren’t rapid.

Relying on what results you’re on the lookout for, it might take just a few weeks to some months to take impact. 

For instance, suppose you’re taking L- arginine or L-citrulline for erectile dysfunction. In that case, you may want to attend one month of continued use for it to take impact.

And keep in mind that erectile dysfunction not solely will depend on nitric oxide, so for those who’re not seeing outcomes but, you could want one thing else.

However suppose you’re taking L-citrulline to enhance muscle efficiency. In that case, the consequences shall be extra noticeable after seven days of taking it every day with out lacking one dose.

Which is best?

Each L-citrulline and L-arginine are wonderful at growing nitric oxide ranges. They can be utilized collectively in the identical dietary supplements with out a downside.

Nonetheless, if it’s a must to select between certainly one of them, most research would level out that L-citrulline is best.

L-citrulline has higher bioavailability. It’s absorbed quicker and stays unchanged within the physique for longer.

In distinction, since L-arginine is extra generally acknowledged by many cells, they take L-arginine and convert it to one thing else earlier than it turns into nitric oxide.

This is called first-pass metabolism. That doesn’t occur with L-citrulline, which reaches the enzymes that convert it to L-arginine after which to nitric oxide with out being modified by different cells and enzymes within the course of.

However then, which one ought to I take advantage of? L-citrulline vs L-arginine for heart problems, erectile dysfunction, or bodybuilding?

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Each are superb if you’re on the lookout for long-term outcomes, corresponding to enhancing your heart problems.

However if you wish to see a really particular impact in your muscle perform or erectile dysfunction, use a mix complement of each or L-citrulline alone.

Ought to I take L-arginine and L-citrulline collectively?

As famous above, L-arginine and L-citrulline are two carefully associated amino acids which have been studied for his or her potential to extend nitric oxide (NO) ranges within the physique.

Taking each of those amino acids collectively might additional maximize the advantages of NO manufacturing, as every of those amino acids is a precursor for the synthesis of NO.

When taken collectively, L-arginine with L-citrulline can work synergistically within the physique to extend NO manufacturing.

L-arginine will produce nitric oxide immediately, and L-citrulline will produce further results and enhance the complement’s bioavailability.

The mix might be helpful for these trying to maximize nitric oxide manufacturing within the physique. These amino acids can work synergistically to extend NO manufacturing, leading to improved circulation, muscle progress, train efficiency, and total well being.


On this assessment of L-citrulline vs L-arginine, we now have seen they’re amino acids concerned within the formation of nitric oxide.

This gasoline molecule is important to regulate blood strain, improve immune perform, and should even enhance bodily efficiency and erectile issues.

Arginine and citrulline supplementation will increase plasma ranges of those amino acids. They’re used to create nitric oxide, which finally makes a distinction in hypertension, erectile dysfunction, and different issues.

Bodybuilders additionally use such a important amino acid complement to extend their bodily efficiency, measured by barbell bench press repetitions, strolling distance, or most load.

One of many most important variations between L-citrulline and L-arginine is that the latter is transformed into different metabolites and waste merchandise.

Arginine degradation leads to a lower in plasma arginine focus. This doesn’t occur with citrulline, which reaches the cells untouched and has higher bioavailability.

Thus, L-citrulline has extra purposes than L-arginine, however they can be utilized together for higher outcomes.

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