If you're interested in insulin, try to get Humalog, its a prescriiption only, but hell I'm assuming your using AAS anyway right? Humalog acts much faster than Humulin R and is out of your system faster. It slams ya pretty quick, but then runs out quickly as well, so it has a sharp peak. The problem I had with R, is the peak is much longer, so after I had my post workout meal, I had to keep eating almost constantly for 4 hours to avoid crash. Humalog is obviously very dangerous, but personally has always been much smoother for me