I am extremely sensitive to niacin, aspirin and benedryl to nothing; I get an EXTREME lower extremity histamine reaction where my legs itch non-stop for hours, uncontrolably to the point it literally takes over my mind; no joke lol, I am a very calm person and almost punched out my mom when she told me to stop scratching, it literally takes over my mind haha. I have to burn my legs with hot water to stop it.. anyways, I do not get any reaction at all from hemavol powder and have used it several times.
Mike