BioEnerGy C. Longevity product. Uses the Ribose gateway, only problem is getting a hold of it. Seems like they haven't been able to ramp production to keep up with demand. But since most peoples problem with high dose Vit C is mouth-gut I guess I can see why. It's the only one my wife will use. I have no such issues and can comfortably consume 25 grams a day with only a little gas.