The Antioxidant Power of Bergamot Polyphenolic Fraction Gold Potentiates the Effects of L-Citrulline in Athlete Performance and Vasodilation in a Pilot Study

Background: The dietary supplement citrulline might increase nitric oxide levels, leading to vasodilation and improved blood flow, potentially benefiting athletes’ aerobic exercise performance. However, rapid oxidative impairment of the L-arginine/nitric oxide (NO) pathway limits these effects. This is countered by Bergamot Polyphenolic Fraction Gold® (BPFG), a strong natural antioxidant. To investigate L-citrulline + BPFG supplementation’s effects, we performed a randomized, double-blind, placebo-controlled pilot trial on athletic performance and blood flow in trained athletes (cyclists). Methods: Random assignment of 90 male athletes resulted in nine different groups: placebo for Group 1, BPFG at 500 and 1000 mg daily for Groups 2 and 3, L-citrulline at 1000 and 2000 mg/daily for Groups 4 and 5, and the combination product of BPFG plus citrulline (N.O. Max) for Groups 6–9. Baseline and 3-month pre- and post-exercise biochemical, reactive vasodilation (RHI), and maximal oxygen consumption measurements were taken for all subjects. Results: Three months of the combination of BPFG and L-citrulline (N.O. Max) produced a significant synergistic effect, markedly increasing NO (p < 0.001 vs. placebo) release and RHI (p < 0.001 vs. placebo). Cardiorespiratory fitness improved significantly with the BPFG and L-citrulline combination, resulting in substantially higher VO2 max, VT1, VT2, and peak power and a significantly lower heart rate (p < 0.01 vs. placebo). No harmful adverse effects were observed. Conclusions: N.O. Max supplementation, providing beneficial effects on the antioxidant state and preserving the vascular endothelium might be a supplementation strategy to improve athletic performance and potentiate results. Given the small sample size, this study serves as a pilot, and further research is needed to validate these findings on a larger scale.