Quote Originally Posted by MESSY_UK
Would your ammune system over time attack the DNP?
I will look for the source post on this, but yes, your immune system can respond negatively to DNP - that's why a portion of users get hives.

Basically, if I remember right the DNP molecules aren't usually noticed by the immune system, until they attach themselves to bigger molecules. When the immune system notices this it reacts strongly, thus the hives. At this point going to a doctor for some Zyrtec is the quickest way to get over it.

I have no idea what percentage of people get hives, but imagine it can't be too high, or people would not use it.