Effects of Pre-Workout Supplement on Performance

Participants were matched for age, body mass, and FFM and randomly assigned to ingest in a double-blind manner either: (1) a flavored dextrose placebo (PLA); (2) a PWS containing beta-alanine (3 g), creatine nitrate as a salt (2 g), arginine alpha-ketoglutarate (2 g), N-Acetyl-L-Tyrosine (300 mg), caffeine (284 mg), Mucuna pruiriens extract standardized for 15% L-Dopa (15 mg), Vitamin C as Ascorbic Acid (500 mg), niacin (60 mg), folate as folic acid (50 mg), and 70 mg of Vitamin B12 as Methylcobalamin (Cellucor C4 Pre-Workout, Nutrabolt, Bryan, TX); or, 3.) the PWS with Citrus aurantium (PWS + S) extract standardized for 30% synephrine (20 mg) (Nutratech Inc., Caldwell, NJ). Supplements were independently packaged by a third party into coded single foil packets for double-blind administration following Good Manufacturing Practices and certified to contain the aforementioned ingredients by VMI Nutrition (Salt Lake City, UT). All supplements had similar color and powdered texture. Participants were instructed to ingest one foil packet per day approximately 15–30 min prior to exercise on training days and in the morning with breakfast on non-training days. Supplement compliance was verified by weekly compliance verification and collecting and counting empty packets.