Advice seems to come only from the experience of the speaker, but promotes a product.
I propose to verify the indications of collaboration and distinguish testimony, promotion and proof of effectiveness. In the example, the appreciation of the creator does not prove that the product is suitable for every reader.
The commercial relationship does not invalidate all information, but helps to interpret its purpose. A decision also requires conditions, costs, and alternatives, especially when it comes to health or well-being.