T3 Conversion Booster is considered a low thyroid support supplement so you generally would not want to take it if you are in a state of thyroid overactivity or hyperthyroidism. Having said that, there are a few situations where it may make sense to use low thyroid support if you have been labeled with hyperthyroidism: #1. If your thyroid has been surgically removed. If your thyroid has been removed then you are considered to be hypothyroid even if the reason for the removal was due to hyperthyroidism. #2. If your thyroid has been ablated with radioactive iodine. If your thyroid has been ablated then you are considered to be hypothyroid even if the reason for the ablation was due to hyperthyroidism. #3. If you are undergoing block and replace therapy or add-back therapy for hyperthyroidism. Block and replace therapy is an uncommon treatment used in some situations where a patient with hyperthyroidism will take both thyroid medication like levothyroxine as well as thyroid blocking medication like methimazole. If you are undergoing this kind of treatment (which is uncommon) then you can consider thyroid support supplements as well. In general, if you are using thyroid-blocking thyroid medication like methimazole then you probably shouldn't use T3 Conversion Booster. On the other hand, if you are taking any sort of thyroid medication replacement like levothyroxine (or any others) then you can consider using T3 Conversion Booster.