title: Ingesting a preworkout supplement containing caffeine, creatine, β-alanine, amino acids, and B vitamins for 28 days is both safe and efficacious in recreationally active men.
abstract: The purpose of this study was to determine the safety and efficacy of consuming a preworkout supplement (SUP) containing caffeine, creatine, β-alanine, amino acids, and B vitamins for 28 days. We hypothesized that little to no changes in kidney and liver clinical blood markers or resting heart rate and blood pressure (BP) would be observed. In addition, we hypothesized that body composition and performance would improve in recreationally active males after 28 days of supplementation. In a double-blind, placebo-controlled study, participants were randomly assigned to ingest one scoop of either the SUP or placebo every day for 28 days, either 20 minutes before exercise or ad libitum on nonexercise days. Resting heart rate and BP, body composition, and fasting blood samples were collected before and after supplementation. Aerobic capacity as well as muscular strength and endurance were also measured. Significant (P < .05) main effects for time were observed for resting heart rate (presupplementation, 67.59 ± 7.90 beats per minute; postsupplementation, 66.18 ± 7.63 beats per minute), systolic BP (presupplementation, 122.41 ± 11.25 mm Hg; postsupplementation, 118.35 ± 11.58 mm Hg), blood urea nitrogen (presupplementation, 13.12 ± 2.55 mg/dL; postsupplementation, 15.24 ± 4.47 mg/dL), aspartate aminotransferase (presupplementation, 34.29 ± 16.48 IU/L; postsupplementation, 24.76 ± 4.71 IU/L), and alanine aminotransferase (presupplementation, 32.76 ± 19.72 IU/L; postsupplementation, 24.88 ± 9.68 IU/L). Significant main effects for time were observed for body fat percentage (presupplementation, 15.55% ± 5.79%; postsupplementation, 14.21% ± 5.38%; P = .004) and fat-free mass (presupplementation, 70.80 ± 9.21 kg; postsupplementation, 71.98 ± 9.27 kg; P = .006). A significant decrease in maximal oxygen consumption (presupplementation, 47.28 ± 2.69 mL/kg per minute; postsupplementation, 45.60 ± 2.81 mL/kg per minute) and a significant increase in percentage of oxygen consumption per unit time at which ventilatory threshold occurred (presupplementation, 64.38% ± 6.63%; postsupplementation, 70.63% ± 6.39%) and leg press one-repetition maximum (presupplementation, 218.75 ± 38.43 kg; postsupplementation, 228.75 ± 44.79 kg) were observed in the SUP only. No adverse effects were noted for renal and hepatic clinical blood markers, resting heart rate, or BP. Supplements containing similar ingredients and doses should be safe for ingestion periods lasting up to 28 days in healthy, recreationally trained, college-aged men.
authors.affiliation: Department of Health and Kinesiology, Georgia Southern University, Statesboro, GA. Electronic address: kkendall@georgiasouthern.edu.
authors.forename: Kristina L
authors.initials: KL
authors.lastname: Kendall
authors.affiliation: Department of Sports Exercise Science, United States Sports Academy, Daphne, AL; Sports Science Institute, MusclePharm, Corp, Denver, CO.
authors.forename: Jordan R
authors.initials: JR
authors.lastname: Moon
authors.affiliation: Department of Health and Kinesiology, Georgia Southern University, Statesboro, GA.
authors.forename: Ciaran M
authors.initials: CM
authors.lastname: Fairman
authors.affiliation: Department of Sports Exercise Science, United States Sports Academy, Daphne, AL.
authors.forename: Brandon D
authors.initials: BD
authors.lastname: Spradley
authors.affiliation: Department of Sports Exercise Science, United States Sports Academy, Daphne, AL; Sports Science Institute, MusclePharm, Corp, Denver, CO.
authors.forename: Chih-Yin
authors.initials: CY
authors.lastname: Tai
authors.affiliation: Sports Science Institute, MusclePharm, Corp, Denver, CO.
authors.forename: Paul H
authors.initials: PH
authors.lastname: Falcone
authors.affiliation: Sports Science Institute, MusclePharm, Corp, Denver, CO.
authors.forename: Laura R
authors.initials: LR
authors.lastname: Carson
authors.affiliation: Sports Science Institute, MusclePharm, Corp, Denver, CO.
authors.forename: Matt M
authors.initials: MM
authors.lastname: Mosman
authors.affiliation: Sports Science Institute, MusclePharm, Corp, Denver, CO.
authors.forename: Jordan M
authors.initials: JM
authors.lastname: Joy
authors.affiliation: Sports Science Institute, MusclePharm, Corp, Denver, CO.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Kim
authors.affiliation: Sports Science Institute, MusclePharm, Corp, Denver, CO.
authors.forename: Eric R
authors.initials: ER
authors.lastname: Serrano
authors.affiliation: Department of Sports Exercise Science, United States Sports Academy, Daphne, AL; Department of Human Performance & Exercise Science, University of Mobile, Mobile, AL.
authors.forename: Enrico N
authors.initials: EN
authors.lastname: Esposito
mesh_terms: D000293:Adolescent; D000596:Amino Acids / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D001806:Blood Urea Nitrogen; D001823:Body Composition / Q000187:drug effects; D002110:Caffeine / Q000494:pharmacology*; D003401:Creatine / Q000494:pharmacology; D019587:Dietary Supplements / Q000009:adverse effects; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000187:drug effects*; D010101:Oxygen Consumption / Q000187:drug effects; D010807:Physical Endurance / Q000187:drug effects* / Q000502:physiology; D011998:Recreation; D000637:Transaminases / Q000097:blood; D016896:Treatment Outcome; D014803:Vitamin B Complex / Q000494:pharmacology*; D055815:Young Adult; D015091:beta-Alanine / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D015091:beta-Alanine; D014803:Vitamin B Complex; D002110:Caffeine; D000637:Transaminases; D003401:Creatine
keywords: Amino acids; Exercise; Human; Nutrition; Supplement