Creatine

Creatine is a naturally occurring compound made in the liver and kidneys from the amino acids glycine, arginine, and methionine. Small amounts are also obtained from foods such as meat and fish. Creatine monohydrate is the most widely studied and clinically supported form of creatine. After ingestion, creatine is taken up by cells and converted into phosphocreatine, which acts as a rapidly available energy reserve. Phosphocreatine donates a phosphate group to adenosine diphosphate (ADP) to regenerate adenosine triphosphate (ATP) during high energy demand. This creatine kinase system plays a key role in muscle energy metabolism and supports repeated bouts of high-intensity exercise, as well as increases in strength and lean body mass when combined with resistance training. Creatine should not be confused with creatinine, which is a metabolic waste product formed from the normal breakdown of creatine and is commonly used as a marker of kidney function, not an indicator of creatine intake or toxicity. The International Society of Sports Nutrition recognizes creatine as one of the most effective nutritional supplements for improving high-intensity exercise performance [1].

Beyond its effects on physical performance, creatine supplementation has been studied for additional benefits. Clinical research shows that creatine can improve memory performance in healthy adults, with more pronounced effects observed in older adults [2]. Ongoing research is exploring creatine’s role in cognitive function and brain resilience, with proposed mechanisms suggesting that improved cellular energy availability may help support brain metabolism, particularly under conditions of metabolic stress [3]. Creatine has also been shown to support metabolic performance and functional capacity in different age groups, including older adults [4].

Overall, clinical evidence supports the safety of creatine monohydrate in healthy adults when consumed at doses commonly used in research, typically 3 to 5 grams per day following a loading phase. Long-term studies show no evidence of adverse effects on kidney function in individuals without preexisting kidney disease [5].