L-citrulline is an amino acid that is primarily known for its role in the urea cycle and as a precursor to L-arginine, which in turn boosts nitric oxide (NO) production. While L-citrulline is most commonly associated with cardiovascular health and exercise performance, there is some scientific rationale for its role in supporting mitochondrial function, though the evidence remains preliminary and not robust.

Mitochondria are the energy powerhouses of cells, relying on efficient blood flow and nutrient delivery for optimal function. By increasing NO production, L-citrulline may enhance blood flow and thus contribute indirectly to mitochondrial efficiency by improving oxygen and nutrient supply. Some preclinical studies suggest that NO can influence mitochondrial biogenesis and function. There is also early research indicating that L-citrulline might reduce oxidative stress, which could further benefit mitochondrial health.

However, direct clinical evidence supporting L-citrulline supplementation specifically for mitochondrial function in humans is limited. Most research focuses on exercise performance, vascular health, or ammonia clearance. Thus, while there is a plausible mechanism and some supporting laboratory data, clinical validation in the context of mitochondrial health remains insufficient.