Structurally related (−)-epicatechin metabolites in humans: Assessment using de novo chemically synthesized authentic standards

► We present improved sample preparation and analytical methods for (−)-epicatechin metabolites. ► These methods provided us with novel insights into the uptake and metabolism of flavanols in humans. ► We identified and quantified structurally related (−)-epicatechin metabolites. ► We found that the stereochemical configuration of flavanols affects their metabolism in humans.