1 interaction related to thyrotoxicosis
Ashwagandha (Withania somnifera) can lower TSH and raise T3 and T4, so it acts on your own thyroid axis on top of the levothyroxine you already take. A randomized trial showed this hormone shift in people with subclinical hypothyroidism, and separate case reports describe ashwagandha-related thyrotoxicosis and painless thyroiditis. Those case reports were not in people taking levothyroxine at the same time, so the additive-overreplacement scenario is plausible but not directly documented.
