肌酸作为一种天然营养素，其增强肌肉力量的效果已得到广泛验证，但其对认知功能的改善作用仍缺乏充分证据支持。
肌酸在体育增强领域的效果明确：研究显示肌肉力量增加5-15%，冲刺性能增加1-5% [1]。国际运动营养学会的声明指出，在健康和患病人群中，从婴儿到老年人，肌酸补充的安全性良好——即使在0.3-0.8克/千克/天的剂量下持续使用长达5年，也未显示不良健康风险 [1]。
然而，肌酸的认知效益证据存在矛盾。早期一项2003年的研究报告肌酸能增加约17.85至26.4分的智商 [1]，但后续研究未能复现该结果。2023年Sandkühler等人进行的高质量随机对照试验，共纳入123名受试者，结果显示效应量仅为0.17标准差，换算为约2.5个智商分值，不具统计学显著性 [1]。
欧洲食品安全局在2024年的评估中审视了10项人体干预研究，最终结论为肌酸补充对认知功能未显示一致效果，因此缺乏充分证据支持其认知益处的宣称 [1]。虽然肌酸可能增加脑内肌酸水平3-10% [1]，且该物质对大脑功能确实至关重要并能跨越血脑屏障，但现有随机对照试验未能验证这种生化变化能否转化为实际的认知改善。
Creatine is a natural nutrient with well-established benefits for muscle strength, increasing it by 5-15% and sprint performance by 1-5% [1]. However, evidence for cognitive enhancement remains inconsistent and largely unconvincing.
While creatine is crucial for brain function and can cross the blood-brain barrier, randomized controlled trials have produced minimal cognitive benefits [1]. A landmark 2003 study by Rae and colleagues reported IQ increases of approximately 17.85 to 26.4 points, yet subsequent research has failed to replicate these findings [1]. A high-quality 2023 randomized controlled trial by Sandkühler and colleagues involving 123 subjects found an effect size of only 0.17 standard deviations, equivalent to approximately 2.5 IQ points and statistically nonsignificant [1].
In 2024, the European Food Safety Authority reviewed 10 human intervention studies and concluded that creatine supplementation has shown no consistent effect on cognitive function [1]. The authority ultimately determined there is insufficient evidence to support claims of cognitive benefits from creatine supplementation [1].
Creatine may increase brain creatine levels by 3-10%, though evidence for this mechanism remains weak [1]. Additionally, vegetarians and vegans may not necessarily have significantly lower brain creatine levels compared to meat eaters [1].
Regarding safety, the International Society of Sports Nutrition has stated that creatine supplementation at doses of 0.3-0.8 grams per kilogram per day for up to five years has shown no adverse health risks in healthy and diseased populations, from infants to older adults [1].