Creatine

Study: A scoping review of randomized clinical trials (RCTs) from 2012 to 2021 investigated creatine’s effects on muscle growth across various populations.

Findings: Creatine is effective for muscle growth in healthy young individuals with adequate resistance training, but results are less consistent in older adults or those with muscular diseases. It enhances maximal strength, power production, and fat-free mass, particularly when combined with resistance training.

Study: A systematic review and meta-analysis of 16 RCTs (1993–2024) evaluated creatine monohydrate’s effects on cognitive function in adults.

Findings: Creatine showed significant positive effects on memory (SMD = 0.31), attention time (SMD = -0.31), and information processing speed (SMD = -0.51), particularly in adults aged 18–60 and females.

Study: A 12-week RCT (UNSW, Australia) with 63 participants examined creatine monohydrate (5 g/day) effects on lean body mass, with and without resistance training.

Findings: No significant difference in lean body mass was observed between creatine and control groups after 12 weeks of resistance training. Initial gains in the creatine group (especially in females) during a 7-day wash-in phase were attributed to water retention rather than muscle growth. The study suggests that 5 g/day may be insufficient for muscle-building benefits, and higher doses (e.g., 10 g/day) or longer studies are needed.

Study: A review of 685 clinical trials analyzed the safety profile of creatine supplementation, focusing on reported side effects and adverse events.

Findings: No evidence supports creatine impairing kidney function. Gastrointestinal issues (4.9% vs. 4.3% in controls) and muscle cramping (2.9% vs. 0.9%) were slightly higher but not statistically significant. Creatine is deemed safe at doses up to 30 g/day for up to 5 years in healthy and clinical populations.

Study: A clinical trial investigated a high single dose of creatine monohydrate (0.35 g/kg) during 21 hours of sleep deprivation, using cognitive tests and brain scans (31P-MRS, 1H-MRS).

Findings: Creatine improved cognitive performance and increased cerebral high-energy phosphates, suggesting potential for mitigating sleep deprivation effects. However, central nervous system uptake is limited, requiring long-term supplementation for detectable changes.

Study: The International Society of Sports Nutrition (ISSN) position stand reviewed creatine’s safety and efficacy in exercise, sport, and medicine.

Findings: Creatine increases intramuscular creatine concentrations, improving high-intensity exercise performance and training adaptations. It shows therapeutic potential in neurodegenerative diseases (e.g., muscular dystrophy), heart ischemia, and rehabilitation, with no significant adverse effects at doses up to 30 g/day for 5 years.