Supplements (all of them) have potential side effects. Not saying don't take them just be cautious of what you put in your body. Know the potential side effects, how to watch for them and how to counteract them if they occur. If you take something with multiple ingredients, read the labels carefully and resears all of the ingredients.
Creatine, for example, can cause hypertension.
Currently, I take a multi vitamin, vitamin E and a power stack supplement from my health food store.
I'm also doing some research into SARM's (Selective Androgen Receptor Modulator's). They are a grey area body building supplement. Originally developed to counteract wasting disease and fight effects of AIDS. They give most of the benefits of steroids without most of the negative side effects. Notice I said most.
They are a grey area because the are legal to buy (labeled "not for human consumption" of "For Lab Use Only") without a prescription.
But I am having a hard time finding good solid data on the ingredients and potential side effects because they are a fairly new item and not enough research has been done.
Edit: I also drink a protein shake every morning mixed with bullet proof coffee.