If it was blue before you got it, then that boost has added to your stats.. And now that it has added to your stats, it's shows as red to state that you shouldn't get it again, as getting it a second time will have no affect
It stops people buying (let's say) 1000 of them and getting 41,000% boost... You only get the original 41% from the first purchase.. Therefore you would avoid buying more than once