A Randomized, Single-Blind, Crossover Study to Evaluate the Efficacy of a Novel Dietary Supplement Blend with L-Citrulline on Biomarkers of Hydration, Muscle Size, Affect, Inflammation, and Muscular Endurance

Introduction: Citrulline is a non-essential amino acid that has previously been shown to improve athletic performance, reduce fatigue, and increase blood flow. The purpose of this study was to examine the efficacy of a novel dietary supplement blend (3D PUMP BREAKTHROUGH®, 3DPump) vs. citrulline alone on changes in muscle volume, fluid shifts, markers of hydration, inflammation, recovery, affect, and muscular endurance.  Methods:  Twenty-eight recreationally active subjects (6 women, 22 men) participated in a randomized, positive-controlled, single-blind, crossover study which involved 4 testing visits (2 workout visits each with a 24-hr follow-up visit).  Participants ingested 3DPump (containing 3g L-citrulline, 1.2g glycerol, 165mg Amla fruit extract) or 8g of L-citrulline alone 45min before an aerobic and resistance training workout.  Assessments of body fluid shifts (via BIA), markers of hydration (urine and serum osmolality, USG, hemoglobin), and appendicular girth were taken before and after exercise while markers of damage and inflammation (neutrophils, CK, ESR, MCP-1, CRP) were taken before and 24 hours after exercise, muscular endurance (reps to failure) was assessed during resistance exercises, and subjective measures of affect and recovery were taken before, after and 24 hours after exercise.  Mixed factorial ANOVAs with dependent t-tests were used to compare treatments. Results: A significant interaction occurred for right thigh circumference; however post hoc testing indicated both groups increased similarly in post workout girth (p<0.05).  A significant interaction occurred for ECF/TBW indicating post workout was greater than pre workout in 3DPump only (p=0.002).  An interaction trend (p≤0.010) occurred for SBP and DBP indicating that 3DPump was uniquely able to significantly lower blood pressure (SBP and DBP) post workout compared to baseline and 24 hours after exercise (p<0.001).  Conclusions: 3DPump, which contains 3g L-citrulline was able to provide similar effects in muscular endurance, muscle pump and other subjective feelings of affect, hydration, damage and inflammation markers, and body fluid shifts as an 8g dose of L-citrulline alone.  3DPump may have unique benefits on improving post exercise vascular tone and ECF/TBW.