**Abstract**

Non-nutritive sweetener (NNS) use has increased exponentially over the last 30 years as industrialized countries attempted, and failed, to battle obesity epidemics. Large studies have now shown that consumption of NNS's does not help obese individuals lose weight. A large number of scientific studies on NNS's effects have many conflicting results, methodological issues, conflicts of interest, while double blind studies represent a small minority of the studies. NNS's have often been considered as a group despite having unique in vivo absorption, distribution, metabolism, and excretion (ADME). Aspartame may be the most desirable NNS due to its rapid degradation in vivo, whereas saccharin and sucralose are worrisome due to their extended stability in vivo. This review will focus on the most ubiquitous NNS's: aspartame, saccharin, acesulfame-K, sucralose, stevia, sugar alcohols (sorbitol, xylitol, and erythritol), and discuss their different chemical structures, metabolism, effect on the gut biome and cancer.

**Keywords:** artificial sweetener, sweet receptor, gut brain axis, obesity, diet
