Figure 2. Plasma caffeine concentration was measured at baseline (prior to supplement ingestion) and at each hour following ingestion of the supplement for a total of 8 hours. PL = Placebo; TR-CAF = Time-release caffeine supplement; CAF = Regular caffeine supplement; AUC = Area under curve * Plasma caffeine concentration for CAF and TR-CAF was significantly greater than PL (p < 0.001). # Plasma caffeine concentration was significantly different between CAF and TR-CAF (p < 0.05). † CAF and TR-CAF showed significantly greater plasma caffeine concentration AUC than PL over the 8 hours (p < 0.0001). ‡ CAF showed significantly greater plasma caffeine concentration AUC than TR-CAF over the 8 hours (p = 0.001).