Remember, there is no substitute for a healthy diet. And it is always best to talk to a nutritionist or your GP before taking anything, especially if you are on other meds, pregnant or trying to get pregnant.
You’d have to really go some to do yourself any harm with supplements but don’t underestimate them; they are powerful and can be life-changing.
Check the free resources below for a summary of nutrient advisory statements and possible interactions with foods and other meds.
If you need more help, please talk to your health professional for advice.
Cautions & Contraindications of Nutrients
There is also a good drug-supplement checker here at Medscape. And another for more US drugs here.