Just to highlight a few points:J Appl Physiol. 1996 Feb;80(2):452-7.
Caffeine counteracts the ergogenic action of muscle creatine loading.
Faculty of Physical Education and Physiotherapy, Department of Kinesiology, Katholieke Universiteit Leuven, Belgium.
This study aimed to compare the effects of oral creatine (Cr) supplementation with creatine supplementation in combination with caffeine (Cr+C) on muscle phosphocreatine (PCr) level and performance in healthy male volunteers (n = 9). Before and after 6 days of placebo, Cr (0.5 g x kg-1 x day-1), or Cr (0.5 g x kg-1 x day-1) + C (5 mg x kg-1 x day-1) supplementation, 31P-nuclear magnetic resonance spectroscopy of the gastrocnemius muscle and a maximal intermittent exercise fatigue test of the knee extensors on an isokinetic dynamometer were performed. The exercise consisted of three consecutive maximal isometric contractions and three interval series of 90, 80, and 50 maximal voluntary contractions performed with a rest interval of 2 min between the series. Muscle ATP concentration remained constant over the three experimental conditions. Cr and Cr+C increased (P < 0.05) muscle PCr concentration by 4-6%. Dynamic torque production, however, was increased by 10-23% (P < 0.05) by Cr but was not changed by Cr+C. Torque improvement during Cr was most prominent immediately after the 2-min rest between the exercise bouts. The data show that Cr supplementation elevates muscle PCr concentration and markedly improves performance during intense intermittent exercise. This ergogenic effect, however, is completely eliminated by caffeine intake.
PMID: 8929583
1) Creatine was administered in 8 equal doses split throughout the day.
2) Caffeine was administered in a single dose following breakfast.
3) The participants followed a standardized diet with a 18/50/32 macronutrient breakdown.
It should also be noted that this study corresponds to around 50g and 500mg of Cr/C respectively for a 100kg individual. This is a significant dose of creatine to be rendered useless by the caffeine.
Bad news for the majority of pre-workout supplements out on the market:icon_lol: