Some people think that if a substance is 'natural' it's healthy. That's not always the case. Strychnine, arsenic and hemlock are also natural substances but are highly toxic. You wouldn't want to ingest them. Nor should you.
Although certain supplements are helpful when you need them, it's best to discuss them with a health care provider or an herbalist. If you don't and just start buying stuff off of a shelf and chugging it thinking you'll lose weight, stop hot flashes,get a better libido,you could have a problem. If you're lucky, the substance you've ingested will merely be ineffective, while other substances are downright dangerous, causing heart, liver and kidney damage. Further, herbs like Black Cohosh has been linked to the spreading of breast cancer, and ingesting soy products have little bearing on hot flashes should you be menopausal. I know this from personal experience.
I'm not saying that you shouldn't supplements them if you need them. But remember that these are medicinal and do have side effects. Please contact a certified herbalist before experimenting with supplement's.
So check out this link and learn more.