L-Citrulline for Blood Circulation

Research suggests that L-citrulline may support blood circulation primarily by increasing plasma L-arginine levels and enhancing nitric oxide (NO) bioavailability, which plays a key role in vascular function. Studies indicate that animal research — including rat, rabbit, and mouse models — found that L-citrulline supplementation, particularly in combination with L-arginine, was associated with improved blood flow and faster recovery from stress-induced circulatory impairment, with one mouse study also noting potential benefits for cold-related vascular sensitivity. A 2025 military nutrition review included L-citrulline among nutritional strategies that may help support blood flow to the extremities in cold conditions, alongside nitrate and L-arginine, though the authors noted significant research gaps remain. It is important to note that the supporting evidence comes largely from animal and preclinical studies, and several other studies in this collection, while touching on related metabolic and vascular pathways, do not directly test L-citrulline's effects on circulation in humans — meaning broader conclusions about its effectiveness in people should be drawn cautiously until more human clinical evidence is available.