L-Citrulline vs. L-Arginine: Which is right for you?
Reviewed by | Dr. Caley Scott, ND
In the world of dietary supplements, amino acids have carved out a significant niche — especially among fitness enthusiasts and those seeking to improve their overall health. Two of the most popular amino acids on the market today are L-citrulline and L-arginine.
Both are renowned for their roles in enhancing nitric oxide production, which can lead to better blood flow and improved cardiovascular health. However, despite their similar benefits, they work in distinct ways and can have different effects on the body.
Choosing the right supplement can be overwhelming, given the plethora of information and opinions available.
By the end of this article, you'll have a comprehensive understanding of what L-citrulline and L-arginine are, how they work, their benefits, and which might be the best choice for your specific needs. Let’s dive into the world of amino acids and explore which one is right for you.
What is L-citrulline?
L-citrulline is a non-essential amino acid, meaning that the body can produce it on its own. Unlike essential amino acids, which must be obtained from the diet, L-citrulline can be synthesized from other nutrients in the body.
It gets its name from the Latin word for watermelon, “citrullus," which is a primary natural source of this amino acid.
How does L-citrulline work in the body?
L-citrulline plays a crucial role in the urea cycle, helping the body eliminate ammonia, a byproduct of protein metabolism. However, its most significant function, especially from a supplement perspective, is its ability to convert into L-arginine in the kidneys.
This conversion process boosts the production of nitric oxide, a molecule that relaxes and dilates blood vessels, supporting blood flow and blood pressure. Enhanced blood flow can lead to better oxygen and nutrient delivery to muscles, which is particularly beneficial during intense physical activity.
What are the benefits of L-citrulline?
The unique properties of L-citrulline translate into several health benefits:
- Support for Exercise Performance and Endurance: By supporting nitric oxide production, L-citrulline can support blood flow to the muscles, which can help combat feelings of tiredness and support overall endurance during exercise.
- Enhanced Recovery Post-Exercise: The support for blood flow facilitated by L-citrulline can also support the proper removal of waste products like lactic acid from the muscles, promoting faster recovery after strenuous workouts.
- Potential Benefits for Cardiovascular Health: Nitric oxide production can help support healthy blood pressure and enhance overall cardiovascular function. This makes L-citrulline a valuable supplement for those looking to support their heart health.
What is L-arginine?
L-arginine is a semi-essential amino acid, meaning that while the body can produce it, there are times when dietary intake becomes necessary, especially during periods of rapid growth, illness, or stress. It is a critical building block for proteins and plays a vital role in various physiological processes.
How does L-arginine work in the body?
L-arginine is best known for its role as a precursor to nitric oxide, a molecule that helps relax and dilate blood vessels. This process enhances blood flow and can support healthy blood pressure.
Additionally, L-arginine is involved in protein synthesis, making it crucial for muscle growth and repair. It also plays a role in the urea cycle.
What are the benefits of L-arginine?
L-arginine's diverse functions in the body contribute to several notable health benefits:
- Support for Nitric Oxide Production and Blood Flow: By supporting nitric oxide levels, L-arginine helps support healthy blood flow, which can enhance physical performance — especially in endurance and high-intensity sports. Healthy blood flow also supports cardiovascular health by supporting healthy blood pressure and arterial function.
- Support for Cardiovascular Health: L-arginine's ability to support the healthy production of nitric oxide and maintain proper blood flow makes it beneficial for heart health.
- Potential Benefits for Immune Function: L-arginine plays a role in the development of white blood cells, which are essential for the immune system. Supplementation can help enhance immune response, especially in individuals under physical or mental stress.
How do L-citrulline and L-arginine compare?
With all of this in mind, let’s take a closer look at how these two supplements compare, and what else you should know.
Mechanisms of action
Both L-citrulline and L-arginine are integral to the production of nitric oxide, a molecule that plays a crucial role in vascular health by promoting the relaxation and dilation of blood vessels. However, they work through slightly different mechanisms.
After ingestion, L-citrulline is converted into L-arginine in the kidneys. This newly formed L-arginine is then used to produce nitric oxide. The conversion process ensures a more sustained increase in L-arginine levels compared to direct L-arginine supplementation, which can be quickly metabolized and excreted.
When consumed, L-arginine directly contributes to the production of nitric oxide. However, its bioavailability is relatively low due to rapid breakdown in the liver.
We use L-arginine in our Libido Boost Gummies to bring you more direct blood flow benefits, alongside Korean red ginseng, horny goat weed, and muira puama for well-rounded support.
Bioavailability and absorption
The body’s ability to absorb and utilize these amino acids differs significantly:
- L-Citrulline: L-citrulline is not subject to the same rapid breakdown as L-arginine, leading to better absorption and sustained increases in L-arginine and nitric oxide levels. This makes it more efficient in achieving the desired physiological effects with smaller doses.
- L-Arginine: Due to its rapid metabolism, L-arginine has lower bioavailability, requiring larger doses to be effective. This can sometimes lead to gastrointestinal discomfort in some individuals.
Potential side effects and safety
Both supplements are generally considered safe when used appropriately, but they do have potential side effects and safety considerations:
- L-Citrulline: Generally well-tolerated with minimal side effects. High doses may cause mild gastrointestinal discomfort but are rare.
- L-Arginine: Can cause gastrointestinal issues like nausea, diarrhea, and bloating, especially at high doses. It may also interact with certain medications, such as blood pressure drugs and medications for erectile dysfunction, so consulting with a healthcare provider is important.
How to choose the right supplement for you
Determining the right supplement often depends on your specific health objectives:
- For Improved Exercise Performance and Endurance: L-Citrulline is typically more effective due to its sustained nitric oxide production and better absorption.
- For Cardiovascular Health: Both supplements are beneficial, but L-Citrulline might offer longer-lasting effects with fewer side effects.
- For Immune Support: L-Arginine may be more advantageous due to its direct role in immune function.
- For Sexual Function: L-Arginine directly supports blood flow and healthy blood pressure, helping improve sexual function in both men women.
Both supplements are suitable for vegetarians and vegans, but sourcing from reputable suppliers is essential to ensure quality.
It's also crucial to consider potential interactions with other supplements or medications. For instance, individuals taking blood pressure medications or erectile dysfunction drugs should consult with a healthcare provider before starting L-Arginine.
Before starting any new supplement regimen, consulting with a healthcare professional is highly recommended. They can provide personalized advice based on your health status, medical history, and specific needs.
What are some sources of L-citrulline and L-arginine?
L-citrulline is naturally found in several foods, with watermelon being the most well-known source. Other good sources include cucumbers, melons, pumpkins, and gourds. These foods can be easily integrated into a balanced diet, offering a natural way to boost L-citrulline intake.
In supplement form, L-citrulline is often available as L-citrulline or citrulline malate. The latter is a combination of L-citrulline and malic acid, which is believed to enhance absorption and efficacy. Supplements are typically found in powder or capsule form and can be taken to specifically target increased nitric oxide production and improved exercise performance.
L-arginine is found in a variety of protein-rich foods. Animal products such as red meat, poultry, fish, and dairy are excellent sources. For those following a plant-based diet, L-arginine can be obtained from nuts, seeds, soybeans, chickpeas, lentils, and whole grains. These foods not only provide L-arginine but also other essential nutrients that support overall health.
L-arginine supplements are widely available in various forms, including capsules, tablets, and powders. They are often used by individuals looking to support cardiovascular health, enhance athletic performance, or boost immune function. Some supplements combine L-arginine with other ingredients like L-citrulline, vitamins, or minerals to enhance their effectiveness.
The bottom line
Deciding between L-citrulline and L-arginine depends largely on your personal health goals and how your body responds to each supplement. Both amino acids are powerful in their own right, offering unique benefits from improved exercise performance to enhanced cardiovascular health, sexual health, and immune support.
L-citrulline tends to offer longer-lasting effects due to its efficient conversion process in the body, making it a preferred choice for athletes and those seeking sustained nitric oxide production. On the other hand, L-arginine is directly involved in protein synthesis and immune function, providing immediate benefits in these areas.
At Sunmed, we understand the importance of making informed choices about your health. While our expertise lies in providing high-quality CBD products, we are also your go-to resource for a wide range of wellness products. Our commitment to quality and customer satisfaction ensures that you receive the best possible support on your health journey.
Whether you're looking to enhance your performance, support your cardiovascular health, or simply improve your overall well-being, Sunmed is here to help you achieve your goals with trusted wellness products and expert advice.
Sources:
Amino Acid: Benefits & Food Sources | Cleveland Clinic
Can L-arginine supplements lower blood pressure? | Mayo Clinic