If you are contemplating taking a vitamin or mineral supplement to improve your health or wellbeing, the Australian Thyroid Foundation recommend asking your GP to order blood tests to determine if you have a deficiency in a particular vitamin and mineral before taking any vitamins or supplements.  

It is recommended to ensure you have a healthy diet which includes all food sources to maintain good health.  

Vitamins and mineral supplements can interact with Levothyroxine, affecting absorption and performance of the medication.

If it is determined you are deficient in a vitamin or mineral, it is advised to increase a particular food source to help overcome the deficiency.  If dietary changes are unsuccessful and a vitamin or mineral supplement is needed, ensure you inform your thyroid treating doctor and have regular Thyroid Function Blood Tests to monitor your thyroid function and monitor your general health and wellbeing to ensure the supplement is not having an affect on how you feel.