Milk thistle’s actions are generally beneficial to the thyroid. The reason It’s contraindicated in hypothyroidism is that it can interfere significantly with medicines commonly used with thyroid conditions. I’ll clarify that on the quickview.
Milk thistle also helps the liver to convert thyroid hormone T4 (thyroxine) to its active form T3 (triiodothyronine). So using it in a case of hyperthyroidism may also be an issue because it may make the excessive T4 being produced more effective…which is bad in that case. Also, it interacts badly with drugs used for hyperthyroidism too.
Don't use herbs or combine herbs with medications or use them during lactation or pregnancy without talking with your healthcare provider.
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