it is not dangerous if you know what you are doing...i have done 3 cycles of it...gets your RBC's up to about the mid 50's if you do it right...you have to do a lot of shit though...iron, b12 shots and folic acid...then you have to get a zipocrit so you can check your RBC count ed and figure out what you need to maintain a hemotocrit of 55%..pm me if you have more questions...i am a mma guy...i use it for every fight