Introduction. TeaCrine® is the pharmaceutically-produced, synthetic version to naturally occurring theacrine (1, 3, 7, 9-tetramethyluric acid) found in the leaves of the Camellia kucha tea plants. Few studies have examined the effects of TeaCrine® on cognitive function, but no research exists examining its effects on exercise performance. As such, the purpose of this study was to examine the effects of TeaCrine® on resistance exercise performance. Methods. Twelve resistance trained men (mean ± SD, age: 23.17 ± 3.10 years; height: 176.53 ± 5.89 cm, weight: 83.24 ± 7.23 kg) were recruited to participate in this study to examine the effects of TeaCrine on resistance exercise performance. Each participant performed (in order) one repetition maximum (1RM) bench press, 1RM squat, bench press reps to failure (RTF) at 70% 1RM, squat RTF at 70% 1RM, and 2km rowing time trial after the consumption one of four treatments (in random order): (1) Caffeine 300mg (CAFF300); (2) TeaCrine® 300mg (TEA300); (3) TeaCrine® + Caffeine combo (150mg/150mg) (COMBO); (4) Placebo (PLA). Visual analog scales for energy, focus, motivation to exercise, and fatigue were administered at baseline and, 90 min post-treatment. Rating of perceived exertion was also assessed after bench press and squat RTF at 70% 1RM. Magnitude based inferences were utilized to examine performance effects in 1RM and RTF for bench press and squat. Performance and perceptual data was also assessed via null-hypothesis testing. Data are presented as mean ± SD. Results. Mean bench press 1RM was 1.3%, 2.2%, and 2% higher in CAFF300 (120.08 ± 16.21 kg), TEA300 (118.94 ± 15.7 kg), and COMBO (119.89 ± 15.96 kg) compared to PLA (17.42 ± 15.52 kg), respectively. Mean squat 1RM was 150.57 ± 23.88, 148.48 ± 25.37, 149.81 ± 23.49, and 147.54 ± 20.8 kg for CAFF300, TEA300, COMBO, and PLA, respectively. Performance in CAFF300, TEA300, and COMBO were 1.8% ,0.2%, 1.3% higher compared to PLA. Mean bench press RTF was 1.4%, 5.0%, 1.5% higher in CAFF300 (12.41 ± 2.71 reps), TEA300 (12.83 ± 2.59 reps) and COMBO (12.50 ± 2.88 reps) compared to PLA (12.25 ± 2.67 reps), respectively. Mean differences in CAFF300, TEA300, and COMBO vs. PLA were 11.3% ,0.7%, 2.4%, respectively. Mean effects between all treatments for muscular strength and endurance were trivial and there were no significant differences between groups (p>0.05). CAFF300, TEA300, and COMBO were not different from PLA for 1RM and RTF in either the bench press or squat (p>0.05). There were no significant differences in peak or average power or velocity for bench press or squat. Only CAFF300 resulted in significant increases in energy (+9.8%; +15.3%), and motivation to exercise (+8.9%, +14.6%) vs. TEA300 and PLA, respectively, and increased focus (+9.6%) vs. TEA300, but no differences from COMBO. Conclusion. CAFF300, TEA300 and COMBO had no significant effect on 1RM, RTF, power or velocity in the bench press and squat. CAFF300 improved measures of focus, energy or motivation to exercise but TEA300, COMBO, and PLA did not.
