High Citrulline: Arginine Ratio: Arginine is a proven precursor to nitric oxide (NO), a vasodilator. What most people don’t know is that arginine supplementation stimulates the activity of arginase, an enzyme that breaks down arginine. Over time, this may actually result in reduced arginine and NO levels, in turn causing your pre-workout formula to stop working. Research suggests that supplementing with a high ratio of citrulline to arginine may reduce this risk by avoiding overstimulation of ar CFB Helps Support Testosterone: In a clinical study, calcium fructoborate (CFB) was shown to increase total and free testosterone within 3 hours of a single dose equivalent to just over 2 scoops of Nitraflex.* A longer-term study reported an increase in free testosterone by up to 29%. Effective Dose of Beta-Alanine*: The clinically-proven performance enhancer beta-alanine was not “fairy dusted” in this formula. Rather, we added a powerful dose that you will feel working following your very first serving. (May promote slight, tingly-cerebral sensation).* Creatine-Free: Creatine causes water retention, which can make achieving a dry, hard muscular look even more difficult. NITRAFLEX contains no creatine, making it ideal for pre-contest prep and lean muscle physique* Cognitive Enhancers*: NITRAFLEX contains unique ratios of scientifically validated compounds that help you remain alert, intense and focused while you’re flying from set to set with veins fully dilated and muscles pumped to the extreme. (DMAE)*.