We're sorry to hear of your thyroid cancer diagnosis but it sounds like you are past it now, thank goodness. The main recommendation for taking Synthroid is to take it away from all of your supplements. The DE and clay we use in the sludgy cocktail will decrease its efficacy. Also, you might find this helpful - our friend Izabella Wentz is known as the Thyroid Pharmacist and she graciously shared with us her eBook on thyroid medications.You might enjoy learning about the different ones.That is available for download in the Bonus module.