This is a topic of huge debate on virtually any board with a lot of R3IGF-1 info. I assume you are buying it in BA? There are those who say it degrades at a fairly rapid pace once reconstitued in BA. They recommend acetic acid or HCl I believe. There are plenty of others who say its fine in BA and I have seen a lot of threads of people who get results with it. This to me looks like one of those try it and see deals. There appears to be no definitive answer. That probably is not the answer you are looking for but its what my research leads me to believe. Hope it helps a little. If you want to do a lot of reading shoot me a PM and I can steer you towards a wealth of info.
Please Scroll Down to See Forums Below 
