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Many compounds in the body serve important roles, and nitric oxide (NO) is one of them. This is because NO helps widen blood vessels and supports circulatory health, which is crucial for ensuring all tissues in the body receive adequate blood. Oddly enough, though, nitric oxide supplements are not the most effective way to increase NO levels in the body.

Instead, one of the best ways to raise NO levels is by supplementing L-citrulline, which is a precursor to NO and boosts NO synthesis. By increasing NO levels in the body, L-citrulline offer health benefits that include circulatory support, cognition improvement, and immune boost.

What is L-Citrulline?

When looking at supplements, it is common to see the name L-citrulline, which simply refers to citrulline on its own. This is in comparison to another citrulline supplement called citrulline malate, which is a combination of citrulline and malate.

Citrulline is a nonessential alpha-amino acid formed by enzymes in the mitochondria, although it was first identified in watermelon. It is considered a nonessential compound not because the body does not need it, but because the body can naturally produce some on its own. However, supplementing the amount of citrulline in the body by eating foods that contain it or taking supplements can offer greater benefits to your health.

Health Benefits of L-Citrulline

Despite being an amino acid, L-citrulline does not build proteins. However, it is a crucial compound for the urea cycle, which removes harmful compounds from the body.

Additionally, many of the health benefits of L-citrulline result from its ability to increase nitric oxide (NO) production. Another compound often included in this pathway, which you will see frequently mentioned in the research detailed below, is arginine. Citrulline increases arginine production, and arginine stimulates the production of NO, which is how supplementing citrulline increases the amount of NO in the body and produces the below benefits.

Increases Exercise Capacity

While L-citrulline does not directly build proteins, it can increase protein synthesis due to its ability to stimulate an important signaling pathway that is used for muscle building.

L-citrulline may also benefit muscle growth by preventing the liver from breaking down certain amino acids, which can then be used to create muscle.

Research has also shown that citrulline can cause an increase in growth hormone (GH) after exercising, which may contribute to the beneficial bodily adaptations seen after exercising.

Decreases Blood Pressure

One role of L-citrulline is acting as a substrate for recycling L-arginine, which is a precursor for the synthesis of nitric oxide (NO). NO is a signaling molecule that helps regulate many body functions, and when the amount of NO available decreases, many age- and lifestyle-related diseases can develop and progress.

L-citrulline offers a way to increase L-arginine and, thus, NO synthesis in the body, with research showing that its supplementation offers many cardioprotective effects, such as lowering blood pressure.

Studies on the benefits of L-citrulline for blood pressure found that after 8 weeks of supplementation, blood pressure levels were reduced by 4-15%.

Other studies have found that benefits to blood pressure can be seen sooner than this, with one study reporting a drop in blood pressure of 6-16% after just 7 days.

Increases Blood Flow

The ability of L-citrulline to decrease blood pressure through increasing NO synthesis is because NO helps widen the arteries and veins, a process called vasodilation. In addition to lowering blood pressure, vasodilation also increases blood flow, which improves cardiac function.

Reduces Erectile Dysfunction

By reducing blood pressure and increasing blood flow, L-citrulline helps to improve cardiac function. This effect is especially beneficial for those with ED due to cardiovascular problems, such as low blood flow.

One study on L-citrulline for erectile dysfunction found that 50% of the participants experienced an increase in erection hardness after taking the supplement, and all the participants seeing these results were very satisfied with the improvements.

Enhances Cognition and Brain Performance

L-citrulline also offers protection to the brain, with one study showing that L-citrulline was able to prevent cerebrovascular injury following a stroke. The study gave mice L-citrulline supplements for 10 days following stroke, and the results showed that the supplement not only prevented neuronal cell death but also prevented the loss of capillaries in the hippocampus. The study also found that L-citrulline addressed memory deficits seen after a stroke.

These neuroprotective effects were also seen in mice with Alzheimer’s because of L-citrulline’s ability to supplement L-arginine. A 2020 study found that supplementing citrulline for 3 months improved long-term spatial memory, suggesting that it can be used as an early treatment to lessen cognitive decline due to Alzheimer’s disease.

Boosts Immune Health

L-citrulline has the ability to modulate regulatory T-cell immune effects, which plays a role in suppressing the immune response and maintaining homeostasis. This is crucial for preventing autoimmune or chronic inflammatory diseases.

Studies have also shown that L-citrulline can help in cases of sepsis, a severe condition characterized by full-body infection. Sepsis causes immune dysfunction, but supplementing citrulline increases arginine availability, which then restores T-cell function and reduces immunosuppression due to sepsis.

L-Citrulline for Improving Health

L-citrulline offers many benefits to the body when supplemented, such as improvements in exercise capacity, decreased blood pressure, greater blood flow, improved cardiac output, enhanced cognition, and boosted immune health. Many of these benefits are due to L-citrulline’s ability to increase arginine and NO in the body, better than arginine or NO supplementation itself can.

For those looking to improve these areas of their life, Glutathione Rapid Boost+ (GRB+) is a low-calorie and caffeine-free sports drink that boosts glutathione (the body’s most important antioxidant) and contains 750mg of L-citrulline, helping to boost L-arginine and NO in the process. This is in addition to Vitamin C, Vitamin B complex, selenium, and L-theanine, among other beneficial compounds.

GRB+ is a perfect choice for those who want a quick and convenient way to significantly boost their daily vitamin and nutrient intake while also getting an energy boost; give it a try today and experience the health benefits of L-citrulline yourself.


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