Methodological Approaches to Bioavailability of Oral Creatine in Randomized Controlled Trials: A Meta-Research Study
Abstract
Background: Creatine is one of the most widely used dietary supplements for enhancing physical performance and is increasingly investigated for a range of health-related applications. Although creatine monohydrate is the most commonly used formulation, concerns have been raised regarding its oral bioavailability, prompting the development of alternative formulations and delivery strategies. However, it is unclear to what extent randomized controlled trials (RCTs) evaluating oral creatine supplementation address issues related to bioavailability. Therefore, we aimed to assess how bioavailability of oral creatine is considered and reported in RCTs. Methods: We conducted a meta-research study of published RCTs in which orally administered creatine was used as an intervention or comparator, regardless of participant characteristics or outcomes. MEDLINE and Embase were searched from inception to 1 March 2024. We extracted data on trial characteristics, creatine formulations used, mentions of bioavailability, and comparisons between different creatine products. Data were summarized descriptively. Results: We included 357 reports corresponding to 343 RCTs published between 1994 and 2023. Creatine monohydrate was the most commonly used formulation, reported in 275 (80.2%) trials; however, 53 (15.5%) reports did not specify the exact creatine form used. Bioavailability was mentioned in only 38 (11.1%) reports, most frequently in the discussion section. Four trials (1.2%) reported…
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Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design.
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