You need to look into Chinese Medicine that has used it for only a few thousand years. As for study’s, would you spend a 100 million $ of your money for a product that is natural and can not be patented? No patent no profit. Big Medicine could care less about you! The faster you get cancer and become a $400,000 profit the better.
Heroin is a natural product. Cocaine is a natural product. Arsenic is a natural product.
All of these are natural and yet not really good for you.