Bottom line up front: All supplements have side-effects.
FACT: This is complete malarkey. Not a single item you take in orally is without side effects. Take beans for instance. I would consider beans to be healthy and natural, but they can give you gas. Everything that you take in orally has side effects and just because it is “natural” has nothing o do with whether it has side effects or not. The fact is that is they are over priced and will not generate long term weight loss.
The bottom line: Avoid most supplements. They will cause more harm than good, and a lot of that harm will be to your pocket book.