In our opinion, purchasing supplements online in general can be a little tricky if the distributing source is unknown, because the supplements may not have been handled or stored safely under the proper conditions, and some even have been shown to have counterfeit labels. Also if you are not familiar with the formulator, the ingredients may not be in the most absorbable form and may not be tested for purity and nutrient levels.
I have made a list there of my “Favorite” supplements that I recommend as well as “protocols” with suggested supplements for men, women and children, and special supplements designed to boost the immune system, most of which our own family is currently taking.