i also read if you filter the prop with a syringe filter it can help with the pain. my theory is when prop is painful, it might be that the powder wasnt cooked properly when brewing and maybe the stuff didnt dissolve fully, leaving you with painful crystals in your muscle once the oil is absorbed. maybe filtering can get some of the crystals out, but i guess that could technically weaken the strength but im not sure about that.
just my thoughts, not sure how accurate it is.