Just make sure if you take Vanadyl Sulfate you start out with a minimal dosage and test your body's tolerance....I can tell you (from personal experience)...if you take too much Vanadyl Sulfate your stomach will pay the price....I had some custom Vanadyl sent to me that was a wee bit overdosed and man....Talk about spending the afternoon in the bathroom...That stuff took me for a ride.
Try to stay within 10-20mg of vanadyl Sulfate and you will get awesome pumps.
Like Jayson said VS along with L-Arganine is excellent.