Pharmacokinetic Profile of Caffeine and Its Two Main Metabolites in Dried Blood Spots After Five Different Oral Caffeine Administration Forms—A Randomized Crossover Study

Abstract

This article has been retracted as of July 17, 2024, after a reader expressed concern that maximum caffeine concentrations in the study were substantially higher than those in earlier reports. The authors of the original article were asked to provide their raw dataset and an explanation for the apparent inconsistencies. During an independent review of the study data in coordination with the authors, they identified a contamination issue with caffeine that affected their evaluation of the results. Because the plausibility of the present data is in doubt due to the contamination issue, the article is retracted.