Abstract
Background
Pre-workout supplements (PWS) have become increasingly popular with recreational and competitive athletes. While many ingredients used in PWS have had their safety assessed, the interactions when combined are less understood.
Objective
The purpose of this study was to examine the safety of 1 and 2 servings of a PWS.
Design
Forty-four males and females (24.4±4.6 years; 174.7±9.3 cm; 78.9±18.6 kg) from two laboratories participated in this study. Subjects were randomly assigned to consume either one serving (G1; n=14) or two servings (G2; n=18) of PWS or serve as an unsupplemented control (CRL; n=12). Blood draws for safety panels were conducted by a trained phlebotomist before and after the supplementation period.
Results
Pooled data from both laboratories revealed significant group×time interactions (p<0.05) for mean corpuscular hemoglobin (MCH; CRL: 30.9±0.8–31.0±0.9 pg; G1: 30.7±1.1–30.2±0.7 pg; G2: 30.9±1.2–30.9±1.1 pg), MCH concentration (CRL: 34.0±0.9–34.4±0.7 g/dL; G1: 34.1±0.9–33.8±0.6 g/dL; G2: 34.0±1.0–33.8±0.8 g/dL), platelets (CRL: 261.9±45.7–255.2±41.2×103/µL; G1: 223.8±47.7–238.7±49.6×103/µL; G2: 239.1±28.3–230.8±34.5×103/µL), serum glucose (CRL: 84.1±5.2–83.3±5.8 mg/dL; G1: 86.5±7.9–89.7±5.6 mg/dL; G2: 87.4±7.2–89.9±6.6 mg/dL), sodium (CRL: 137.0±2.7–136.4±2.4 mmol/L; 139.6±1.4–140.0±2.2 mmol/L; G2: 139.0±2.2–138.7±1.7 mmol/L), albumin (CRL: 4.4±0.15–4.4±0.22 g/dL; G1: 4.5±0.19–4.5±0.13 g/dL; G2: 4.6±0.28–4.3±0.13 g/dL), and albumin:globulin (CRL: 1.8±0.30–1.8±0.28; G1: 1.9±0.30–2.0±0.31; G2: 1.8±0.34–1.8±0.34). Each of these variables remained within the clinical reference ranges.
Conclusions
The PWS appears to be safe for heart, liver, and kidney function in both one-serving and two-serving doses when consumed daily for 28 days. Despite the changes observed for select variables, no variable reached clinical significance.
To access the supplementary material to this article, please see Supplementary files under ‘Article Tools’
To access the supplementary material to this article, please see Supplementary files under ‘Article Tools’
Acknowledgements
We thank all of the participants as well as MusclePharm Corporation for supplying product and funding the investigation. JJ, PF, RV, MM, CT, LC, DK, DC, MK, and JM participated in data collection for Lab 1. RP and JW participated in data collection for Lab 2. All authors contributed to the conception of the experimental design, drafting of the manuscript, and interpretation of data. All authors have read and approved the final manuscript.
Funding source
This investigation was funded by MusclePharm Corporation.
Conflict of interest and funding
JJ, PF, RV, MM, CT, LC, MK, and JM are employees of the funding source, MusclePharm Corporation. However, the remaining authors have no financial interests concerning the outcome of this investigation. Additionally, this publication should not be viewed as endorsement by the investigators, the United States Sports Academy, the University of Tampa, or MusclePharm Corporation.
Notes
To access the supplementary material to this article, please see Supplementary files under ‘Article Tools’