L-Citrulline

Citrulline (α-amino acid)

A naturally occurring amino acid that converts to L-Arginine in the kidneys — producing more sustained nitric oxide elevation than direct L-Arginine supplementation, making it superior for cardiovascular and athletic performance support.

Benefits: Cardiovascular Support, Energy, Hormonal Support, Performance
Type: Amino Acid
Forms: Capsule, Powder

What Is It?

L-Citrulline is a non-essential amino acid found abundantly in watermelon (its name comes from Citrullus lanatus, the Latin name for watermelon). Unlike direct L-Arginine supplementation, L-Citrulline bypasses intestinal breakdown and converts to L-Arginine in the kidneys — resulting in higher and more sustained blood arginine levels.

This makes L-Citrulline one of the most effective supplements for supporting nitric oxide production, blood flow, and cardiovascular health.

How It Works

After absorption, L-Citrulline travels to the kidneys where it is converted into L-Arginine. This conversion pathway avoids the digestive degradation that limits direct L-Arginine absorption, resulting in significantly higher plasma arginine levels.

The resulting increase in L-Arginine then drives nitric oxide synthesis, promoting vasodilation, improved blood flow, reduced blood pressure, and enhanced oxygen and nutrient delivery to muscles. L-Citrulline also plays a role in the urea cycle, helping remove ammonia from the body during intense exercise — reducing fatigue.

Side Effects & Considerations

L-Citrulline has an excellent safety profile and is one of the best tolerated performance supplements available:

- Generally very well tolerated even at higher doses
- May cause mild digestive discomfort in sensitive individuals
- May lower blood pressure — use caution with blood pressure medications
- Those with low blood pressure should monitor carefully
- Pregnant or nursing women should consult a healthcare provider before use
- No significant adverse effects reported in clinical studies at standard doses

Typical Dosage Range

3,000mg – 6,000mg daily

Clinical studies typically use 3-6g of L-Citrulline or 6-8g of Citrulline Malate (a common combined form). For pre-workout performance benefits, take 30-60 minutes before exercise. For cardiovascular support, consistent daily dosing is recommended regardless of exercise timing.

Research Notes

- Pérez-Guisado & Jakeman (2010) — Published in Journal of Strength & Conditioning Research, found citrulline malate supplementation significantly improved athletic performance and reduced muscle soreness by 40% compared to placebo.

- Ochiai et al. (2012) — Study in Hypertension Research demonstrated that L-Citrulline supplementation significantly reduced arterial stiffness and blood pressure in middle-aged men.

- Sureda et al. (2010) — Research in Free Radical Research showed citrulline supplementation reduced markers of muscle damage and improved exercise recovery.

- Bailey et al. (2015) — Published in Journal of Applied Physiology, found citrulline supplementation improved oxygen uptake efficiency and exercise tolerance.

* These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.