Vanadyl is possibly harmful. There are better products available
Vanadyl finds its uses in mimicking Insulin, much like ALA. It regulates blood-sugar levels and helps the uptake of glucose into the cells, instead of turning it to fat. So it promotes the efficacy of creatine and protein. Vanadyl sulfate is derived of the trace mineral vanadium, and is in effect a salt. Users claim they get an increased pump from it.
But what I dont like is the toxicity level of vanadyl. Though the recommended doses are far below toxic, they are also far below effective. They recommend 25-50 mg, prior to workout or after a meal, but the effective dose for bodybuilders lies closer to 75 mg. The toxicity level starts at 100 mg for most people.
So what's the problem ?
75 isn't 100. True, but like all trace minerals, vanadium remains in the body longer than you would like, and as you keep using it, the body level of vanadium keeps going up. Vanadyl accumulates in bone, kidneys and in high concentrations in the liver. For someone watching this closely it's not a true problem, but your multi-vitamin and several other supplements contains small amounts of vanadium as well. As a result using vanadyl requires cycling it 3 weeks on, 12 weeks off. The standard RDA is 10 mcg, that's a tenth of a gram. So what is the use of extra, for the little benefit it has. You'll find ALA to be more effective for a similar price.
Vanadyl has uses in medical conditions, but most nutritionists will advise you to avoid vanadyl if you are in good shape. They have little use, plus there are many other insulin potentiators that work just as well.