How long can platelet rich plasma sit at room temperature and still be used in hair loss? Hello, we are conducting an experiment on Selective Serotonin Reuptake Inhibitor induced hair loss (post treatment). We have all the legitimate tools for harvesting plasma rich proteins for use in hair loss. I go to the phlebotomy lab where my blood is harvested in 8ML PRP tubes containing sodium citrate and gel and the blood is centrifuged and PRP is harvested. We don’t use activators like calcium chloride or anything, but my concern is that sometimes there is a gap of 4-5 hours in which the harvested plasma rich protein sits at room temperature before I can get into my appointment with my physician to have her re-inject the blood plasma into my scalp. Will the harvested PRP work after setting for 4-5 hours at room temperature without activators? Will I still receive benefit from the PRP? I read on PubMed that PRP is good at room temperature for up to six hours, is that so? Thank you