L-Arginine or L-Citrulline: Which One of 2 Boosts Nitric Oxide Better for Athletics, Recovery, and Heart Health?

L-Arginine or L-Citrulline? Which one is better? Blood flow is key in sports performance, muscle recovery, and heart health. Good circulation delivers oxygen, nutrients, and hormones to your muscles and heart. These are vital to improving how you perform and recover. Yet, this important system is often overlooked.

The heart of this process involves Nitric Oxide (NO), a gas made in the endothelium. It works as a signaling molecule and loosens vascular smooth muscles, which makes blood vessels widen—a process known as vasodilation.

Nitric Oxide does more than help athletes. It:

• Lowers blood pressure
• Supports a healthy endothelium
• Helps cells respond to insulin
• Aids in brain and sexual functions

Because nitric oxide plays such an important role in multiple systems, many people want to find natural ways to boost it. L-arginine and L-citrulline are two of the most studied options in this area. You’ll often see both in supplements aimed at workouts, heart health, or NO enhancement. But which one gets you the best results? L-Arginine or L-Citrulline?

At Rambodfit, we’ve provided you with the answers you want to see which one is better. L-Arginine or L-Citrulline?

L-Arginine or L-Citrulline?

To know the exact answer to which one is better? L-Arginine or L-Citrulline, you should know the mechanisms of them and how the physiology of the human body responds to them.

L-Arginine or L-Citrulline can both have benefits if consumed properly with the right purpose.

Here is are explanation of both of them that can help you decide which is better? L-Arginine or L-Citrulline?

What Is L-Arginine?

L-arginine is known as an essential amino acid. This means your body can produce it in normal situations. However, during physical stress, injuries, or heavy exercise, your body may not manage to make enough.

Its main significance lies in being a direct substrate used by nitric oxide synthase (NOS). This enzyme transforms arginine into nitric oxide (NO). Arginine also serves as a building block to produce creatine, polyamines, proline, and urea, which makes it vital to support various metabolic processes.

Foods rich in arginine include:

• Meats like beef and pork
• Poultry like chicken and turkey
• Dairy products such as milk, cheese, and yogurt
• Seafood like shrimp and salmon
• Seeds and nuts like walnuts and sesame

Key roles of L-arginine:

• Triggers the sudden widening of blood vessels
• Helps regulate the immune system through macrophages
• Aids in repairing wounds and forming collagen
• Boosts the release of growth hormone
• Could improve male sexual health by increasing blood flow to the penis

But taking arginine as a supplement by mouth has a big issue with how much the body can use, making it less useful—this will be explained more soon.

What Is L-Citrulline?

L-citrulline, a non-essential amino acid, was first found in watermelon (Citrullus vulgaris). Citrulline, unlike arginine, does not directly make nitric oxide. Instead, it turns into arginine in the kidneys, which increases the level of arginine in the blood more than taking arginine itself.

You can find it in foods such as:

• Watermelon provides the most citrulline.
• Cucumbers offer a decent source.
• Gourds and squash also contain citrulline.
• Pumpkins are another natural option.
• Bitter melon includes it too.

Citrulline has gained importance in performance nutrition because it:

• Has superior absorption in the body.
• Helps maintain elevated nitric oxide levels for a longer time.
• Lessens feelings of fatigue during physical activity.
• Supports the process of building muscle proteins.
• Helps reduce lactic acid and ammonia buildup.

The best type for athletes is Citrulline Malate. It combines citrulline and malic acid, which helps fuel energy production through the Krebs cycle and regenerates ATP.

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Key Advantages: A Direct Comparison

L-Arginine’s Advantages:

• Vasodilation: Arginine causes blood vessels to widen, leading to better blood flow and helping deliver nutrients while exercising.
• Male Sexual Health: Research shows L-arginine supports erectile health by boosting nitric oxide production in the body.
• Immune Function: It helps the immune system respond better, which speeds up recovery after hard physical activity.

L-Citrulline Benefits:

• Extended Blood Vessel Relaxation: Citrulline raises NO levels longer than arginine does, which keeps blood vessels relaxed for an extended period.
• Less Muscle Fatigue: Citrulline lowers muscle exhaustion, allowing better endurance during activities.
• Better Protein Creation in Muscles: Citrulline improves how the body makes proteins after a workout, helping muscles recover faster.
• Managing Lactate and Ammonia Levels: Citrulline controls the buildup of lactate and ammonia that cause muscle tiredness when exercising hard.

Pro Tip #1: The Sexual Health Link

Both L-Arginine and L-Citrulline work as PDE5 inhibitors, similar to how drugs like sildenafil (Viagra) function. They achieve this by increasing NO levels, which helps widen blood vessels in the penile tissues.

Clinical studies have found that citrulline supplements show good potential in helping men with mild or moderate erectile dysfunction. These studies report better erection firmness and more frequent intercourse with no reported side effects.

This is why these amino acids are common in male enhancement pills and pre-workout formulas. They serve a dual purpose—improving performance in the gym as well as in the bedroom.

Which One Is More Effective? L-Arginine or L-Citrulline?

The quick answer: L-Citrulline comes out ahead.

Here’s a closer look at why.

When you take L-arginine in pill form, the enzyme arginase breaks down much of it in your liver and intestines. This process means around 70% of the dose doesn’t enter your bloodstream, which lowers its ability to boost NO levels.

L-citrulline works. It skips arginase, gets turned into arginine by the kidneys, and keeps plasma arginine levels higher and steadier. Several studies back up this process.

• A 2010 study in the British Journal of Clinical Pharmacology showed that citrulline raised plasma arginine levels more effectively than arginine itself. It also helped improve how the endothelium functions under certain conditions.
• Cyclists in a 2017 experiment who took citrulline saw gains in time-to-exhaustion and lowered how hard the effort felt when compared to those who got a placebo.

When you add Citrulline Malate, it’s not just about boosting nitric oxide. The malic acid in it helps recycle ATP, increase power output, and ease muscle soreness after physical activity.

How Much to Take for Best Results

To get the most out of citrulline, using the right amount is important. Experts suggest these dosages as general guidelines.

• L-Arginine: Take 3 to 6 grams daily.
• L-Citrulline: Use 3 to 6 grams per day. If you’re using Citrulline Malate, a common mix is two parts Citrulline to one part Malate.

Keep in mind that taking more Arginine can lead to bloating or diarrhea in some people. It’s best to start with a smaller dose to see how your body reacts.

How Nitric Oxide Helps Beyond Workouts

Nitric Oxide supplements don’t boost muscle pumps. These amino acids play a big role in keeping your body healthy over the long run.

• Hypertension Control: L-arginine and L-citrulline improve blood vessel flexibility, which helps maintain normal blood pressure.
• Preventing Atherosclerosis: These amino acids encourage better blood flow, which lowers the risk of hardening arteries and plaque buildup over time.
• Diabetes and Circulation Issues: Citrulline increases blood flow, which can be helpful to those with diabetes, as poor circulation is a common problem.
• Aging and Vessel Stiffness: Blood vessels get less flexible with age. Using citrulline can support healthy endothelial function and cut down on heart issues tied to aging.

Pro Tip #2: The Golden Stack – Citrulline + Vitamin B12

Here’s the real gem: combining L-citrulline with methylated vitamin B12 (like methylcobalamin) creates a powerful boost to blood vessel health.

Here’s why it works:

• Citrulline helps widen blood vessels by raising NO levels.
• Vitamin B12 lowers homocysteine, which makes blood vessels stiff and raises heart disease risk.

When paired, they improve how the blood vessel lining works, fight oxidative damage, and calm inflammation in the vessels.

This combination could be helpful not only to athletes but also to those facing risks like:

• High blood pressure
• Heart attacks or reduced blood flow
• Diseases affecting peripheral arteries

New studies hint that this mix might slow down mental decline since proper blood flow in the brain is tied to NO levels and the condition of the endothelium.

New Uses and Research Directions

1. Cognitive Performance: NO plays an important part in brain signaling and maintaining blood flow to the brain. Many people are now exploring L-citrulline to boost mental sharpness, improve focus, and recover brain health after injuries.
2. Pre-diabetes and Insulin Sensitivity: Studies have shown that L-citrulline might help the body use glucose more efficiently. This is believed to happen by improving blood flow in the muscle tissues that rely on insulin.
3. Longevity and Vascular Aging: As people age, the lining of blood vessels works less, which reduces NO levels. Taking supplements like citrulline and arginine could help slow down the stiffening of blood vessels, supporting healthy aging of the heart and blood circulation.

You can read about The Role of Nitric Oxide in Cardiovascular Health on PubMed to know more academically about the mechanism and decide which is better. L-Arginine or L-Citrulline?

Conclusion: The Best Option to Improve Blood Flow and General Performance

If you want to improve your performance, speed up recovery, and keep your heart healthy long-term, L-citrulline in its malate form is the best choice.

It raises plasma arginine levels better, boosts endurance, eases soreness, and works well when paired with compounds like B12. This makes it a versatile option.

While L-arginine can still play a role for short-term use or when combined with other nutrients, citrulline offers more lasting benefits. It helps you unlock the full power of nitric oxide without causing major digestion issues.

If you’re lifting weights, going for a long run, or just trying to feel more energetic each day, citrulline can give you a boost. It can also help your heart stay healthy while improving your performance.

So, let me ask you a question: L-Arginine or L-Citrulline?

Here are some other useful articles you can read:

• Vitamin A For Health: 4 Best Benefits for Success, and Healing
• 14 Essential Trace Minerals: Boosting Health and Energy
• Creatine And Gaining Muscle: 4 Best Ways How

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