Summary
Researchers conducted a systematic review and meta-analysis to determine whether adding creatine supplementation to resistance training produces measurable increases in muscle hypertrophy when assessed with high-quality imaging techniques like MRI, CT, or ultrasound. Ten randomized controlled trials lasting at least six weeks met the criteria, yielding 44 regional hypertrophy outcomes in healthy adults. When all data were pooled, creatine combined with resistance training produced only a very small advantage over training with placebo, with a standardized effect size of 0.11—just slightly favoring creatine. Multivariate analyses showed similarly modest improvements in both upper- and lower-body muscle thickness (about 0.10–0.16 cm). Subgroup analysis suggested that younger adults might experience somewhat greater benefits from creatine than older adults, though the confidence intervals were wide and crossed zero. Overall, the findings indicate that creatine supplementation provides a small but real boost to muscle growth when paired with resistance training, confirming its role as a modest enhancer of skeletal muscle hypertrophy.
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Abstract
The purpose of this paper was to carry out a systematic review with a meta-analysis of randomized controlled trials that examined the combined effects of resistance training (RT) and creatine supplementation on regional changes in muscle mass, with direct imaging measures of hypertrophy. Moreover, we performed regression analyses to determine the potential influence of covariates. We included trials that had a duration of at least 6 weeks and examined the combined effects of creatine supplementation and RT on site-specific direct measures of hypertrophy (magnetic resonance imaging (MRI), computed tomography (CT), or ultrasound) in healthy adults. A total of 44 outcomes were analyzed across 10 studies that met the inclusion criteria. A univariate analysis of all the standardized outcomes showed a pooled mean estimate of 0.11 (95% Credible Interval (CrI): -0.02 to 0.25), providing evidence for a very small effect favoring creatine supplementation when combined with RT compared to RT and a placebo. Multivariate analyses found similar small benefits for the combination of creatine supplementation and RT on changes in the upper and lower body muscle thickness (0.10-0.16 cm). Analyses of the moderating effects indicated a small superior benefit for creatine supplementation in younger compared to older adults (0.17 (95%CrI: -0.09 to 0.45)). In conclusion, the results suggest that creatine supplementation combined with RT promotes a small increase in the direct measures of skeletal muscle hypertrophy in both the upper and lower body.
Keywords: lean mass; muscle cross-sectional area; muscle thickness; nutritional supplements; strength training.
Burke R, Piñero A, Coleman M, Mohan A, Sapuppo M, Augustin F, Aragon AA, Candow DG, Forbes SC, Swinton P, Schoenfeld BJ. The Effects of Creatine Supplementation Combined with Resistance Training on Regional Measures of Muscle Hypertrophy: A Systematic Review with Meta-Analysis. Nutrients. 2023 Apr 28;15(9):2116. doi: 10.3390/nu15092116. PMID: 37432300; PMCID: PMC10180745.