The variability of PRP is a major contributor to the lack of evidence regarding the therapeutic effect of PRP in musculoskeletal diseases. In a large study, we are currently investigating factors that may influence PRP variability. Interim results showed that concentrations of IL‑6, but not IGF‑1 or cellular constituents, were significantly decreased in PRP samples from vegans compared with omnivores and tended to be decreased compared to samples from vegetarians. This suggests that diet …