Aspartame, saccharin, cyclamates, and sucralose are all non-nutritive sweeteners that are the subjects of many tests and statements. Saccharin, 30 times sweeter than sugar, was banned then allowed again in the US, and cyclamates are still banned there.
Both are available in Australia. Sucralose is made from sugar, but is 600 times sweeter, has no joules yet tastes like sugar with no aftertaste. Aspartame, 180 times sweeter than sugar, has been declared safe by the USFDA, although tests and controversy continues. Its taste advantage is that it lacks the bitter after-taste of saccharine. Cyclamates are often added to saccharine to mask this flavour.