Vitargo is excellent, but personally I use Professional Supplements "Pure Karbolyn"--essentially the same type of product but less expensive. By the way, don't be fooled by the hype concerning waxy maise starch. It's not the source of the carbohydrate, but, rather, the special processing that makes Vitargo/Pure Karbolyn so rapidly absorbed.
Originally, Vitargo was made from waxy maise starch (but no longer is so) specially modified/processed. So, other supplement companies wanting to make a buck jumped on the WMS bandwagon and starting selling plain unmodified WMS; however, this stuff DOES NOT have the properties of Vitargo/Pure Karbolyn no matter what the companies claim. It's just plain old starch--a pure con. It's no better, no worse, than any other concentrated starch source.
Anyone who has tried both types of products knows exactly what I'm talking about.