Protein fractional turnover rates (FTR) represent measurements of flux through a protein pool, i.e. net abundance (ABD) of the protein. If protein abundance is not measured or is different between experimental conditions the interpretation of FTR data may be confounded. This project investi-gates the consequences of reporting turnover rates of human muscle proteins in vivo in mole and absolute units (that incorporate protein abundance data) compared to fractional (%/d) data that ignore protein abundance. Three physically active males (21 ± 1 years) were recruited and un-derwent a 12-d protocol of daily deuterium oxide (D2O) consumption and biopsies of vastus lat-eralis on days 8 and 12. Protein abundances were normalised to yeast alcohol dehydrogenase, added during sample preparation, and FTR was calculated from time-dependent changes in pep-tide mass isotopomer profiles. FTR and abundance data (fmol/ μg protein) were combined to calculate molar turnover rates (MTR; fmol/ μg protein/ d) and absolute turnover rates (ATR; ng/ d). Abundance data were collected for 1,772 proteins and FTR data were calculated from 3,944 peptides representing 935 proteins (average 3 peptides per protein). The median (M), lower- (Q1) and upper-quartile (Q3) values for protein FTR (%/d) were M = 4.39, Q1 = 0.96, Q3 = 7.84. Our analyses suggest MTR data is preferred over FTR, particularly for studies on multiprotein com-plexes, wherein MTR takes account of potential differences amongst the molecular weight of the component subunits. ATR data may be preferred over MTR and FTR, particularly when compar-ing samples with different abundance profiles.