Standard protocols suggest 5% vol/vol. We have had great luck at that concentration. There is one big difference between our hPLs and FBS: You CAN use too much PLTMax® or PLTGold®. It will slow growth of MSCs at high concentrations. But feel free to titrate it to maximize the growth of your cells (between 2-10%). We have reports of different concentrations required with different base medias and different cells.