Creatine is the most widely used supplement for increasing strength performance (Lanhers 2015). The most common form used for supplementation is creatine monohydrate, which has shown to increase fat free mass and improve exercise performance, particularly along with concurrent heavy resistance training. Creatine may benefit other exercise types including high-intensity sprints or endurance training. Creatine monohydrate supplementation may also enhance muscle recovery from intense exercise. (Cooper 2012, Rawson 2018)
Most of the creatine in the human body is in two forms; either in the phosphorylated form or the free form, accounting for 60% and 40% of total stores, respectively (Cooper 2012). Approximately 95% of the body's creatine stores are located in skeletal muscle with the remaining 5% found in the liver, brain, kidneys, and other tissues (Cooper 2012). Intense exercise depletes muscle creatine stores, but supplementing creatine can help replenish this fuel source (Rawson 2018). Supplementing creatine leads to increased creatine levels in the body. Creatine monohydrate supplementation increases muscle creatine by about 20% (Rawson 2018). Anaerobic exercise that relies heavily on creatine to resynthesize energy stores (ATP) can be improved with supplementation (Rawson 2018).
Creatine has been shown to increase strength performance. A meta-analysis by Lanhers (2015) evaluating lower-limb strength performance for exercise with duration < 3 min, found that creatine supplementation improved strength performance with increases in maximal weight lifted during squat and leg press. Similarly, another meta-analysis by Lanhers (2017) evaluating upper limb strength, found creatine is effective at improving upper limb strength independent of training method, dosing strategy, or population characteristics.
Creatine has exhibited effects on short duration, intermittent, anaerobic exercise performance by improving work and power. Most of the beneficial effects of creatine supplementation are demonstrated in anaerobic exercise, since the ergogenic potential on aerobic exercise decreases with activity greater than 2.5 min. Creatine supplementation has also demonstrated improvements in muscle damage and recovery following intense exercise through decreases in markers of muscle damage and creatine's antioxidant effects. (Cooper 2012)
Typical protocol for supplementing creatine usually requires a loading phase of 20-25g of creatine monohydrate per day for 4-5 days to quickly saturate muscle creatine stores, followed by a maintenance period of 3-5g/day. Recent research suggests creatine supplementation of 0.1g/kg of body weight combined with resistance training is sufficient at improving training adaptations. (Cooper 2012)
Cooper R, Naclerio F, Allgrove J, Jimenez A (2012). Creatine supplementation with specific view to exercise/sports performance: An update. Journal of the International Society of Sports Nutrition, 9(1), 33-33.
Lanhers C, Pereira B, Naughton G, Trousselard M, Lesage F, Dutheil F (2017). Creatine supplementation and upper limb strength performance: A systematic review and meta-analysis. Sports Medicine, 47(1), 163-173.
Lanhers C, Pereira B. Naughton G, Trousselard M, Lesage F, Dutheil F (2015). Creatine supplementation and lower limb strength performance: A systematic review and meta-analyses. Sports Medicine, 45(9), 1285-1294.
Rawson ES, Miles MP, Larson-Meyer DE (2018). Dietary supplements for health, adaptation, and recovery in athletes. International Journal of Sport Nutrition and Exercise Metabolism, 28(2), 188-199.