Erythritol is derived naturally from fruits/fermented food. Its 60–70% as sweet as table sugar but its non-caloric, doesnt affect blood sugar, doesnt cause tooth decay, and is absorbed by the body, so its unlikely to cause gastric side effects unlike other sugar alcohols. It also has a cooling effect much like mint and has a way of starving the bacteria in your body (woohoo bye bye gas lol). You can buy it online as it is FDA approved. The Chinese have been using it for generations, which makes alot of sense why they're so slim, hehe.
Also forgot to mention that it works better than Splenda and other sweetners in baking, and unlike other sugar alcohols or substitutes, it doesn't harm the colon,liver or kidneys as studies have suggested for majority of sugar alternatives--especially because it's made naturally whereas Splenda and other sweetners are made artificially :(
You can find it online anywhere, I posted one link that offers it in powder form I believe, I like it better in liquid form.