Take a whole packet of 5 or 6 heart vitamins from gmc store that come together and one aside for thyroid function. is this safe??even with medication?

Maybe, maybe not: It all depends on what is in the vitamins that you take. Anything can be bad for you if the dosage is too high, even things that we think of as natural, like vitamins. Some medications can also interact with vitamins. In particular, thyroid medications and blood thinners can interact with supplements. If you take prescription medications, you could ask your prescribing doctor or your pharmacist.