The weight loss industry in Australia is huge.
There are all sorts of different supplements out there that claim to have dramatic effects, but they are never very effective when studied properly.
The main reason they can work for some people is the placebo effect. People fall for the marketing and want the supplements to help them lose weight, so they become more conscious of what they eat, at the same time they normally increase activity AND start taking the supplement. So it can be hard to know what is giving the benefit if everything is changed at once.
Most supplements for weight loss are completely useless. The best ones can help you lose a moderate amount of fat, at most.