Benefits
Endurance: time to exhaustion in a cycling test
In a randomized, double blind crossover trial in 48 physically active men, 500 mg the evening before and 500 mg one hour before testing increased time to exhaustion at high intensity by about 9.7% versus placebo, and maximal perceived exertion was reached later. It was one manufacturer funded study of an acute dose.
Nitric oxide and blood flow: proposed, not measured
The trial paper, which a Nexira employee co-wrote, cites unpublished cell and animal work suggesting the blend raises nitric oxide production. The human trial did not measure nitric oxide or blood flow, and heart rate, blood pressure and oxygen use were the same as on placebo, so a circulation effect has not been shown in people.
Antioxidant content
The blend scores highly on the ORAC test, a lab measure of antioxidant capacity. No human study has measured whether Vinitrox reduces oxidative stress during exercise, so this describes the ingredient rather than a demonstrated effect in the body.
Mechanism of action
Nitric oxide signalling
The trial authors cite unpublished observations that the blend increased nitric oxide synthase activation in human endothelial cells and nitric oxide dependent relaxation of rat aortic rings. These are unpublished preclinical data and were not tested in the human trial.
Antioxidant activity
Grape and apple procyanidins and flavanols scavenge free radicals in lab assays, which is reflected in the blend's ORAC score. Whether this protects muscles or blood vessels during exercise has not been studied in people taking Vinitrox.
Clinical trials
Randomized, double blind, placebo controlled crossover trial: 500 mg of Vinitrox (two 250 mg capsules) the evening before and one hour before a constant load cycling test to exhaustion, versus maltodextrin placebo. (Deley et al. 2017, Nutrients)
48 healthy, physically active men averaging 31 years old who exercised 3 to 6 hours a week.
Time to exhaustion rose by 9.7% with polyphenols versus placebo (p<0.05), and maximal perceived exertion came 12.8% later. Heart rate, blood pressure, oxygen use and ventilation were similar between conditions, while oxygen use recovered slightly more slowly after the test with polyphenols (half recovery time 8.5 seconds longer). No adverse events. Nexira funded the study and one author was a Nexira employee.