Ashwagandha (KSM-66) and Levothyroxine: interaction, severity and spacing
Ashwagandha (KSM-66) and Levothyroxine interact because ashwagandha can raise circulating thyroid hormone levels, which stacks with levothyroxine and risks iatrogenic hyperthyroidism. Take them with care. Moderate risk.
The interaction in detail
| Pair | Ashwagandha (KSM-66) and Levothyroxine |
|---|---|
| Type | Nutrient–drug interaction |
| Severity | Moderate |
| Required spacing | None specified |
| Onset | At the time of dosing |
Mechanism
Ashwagandha can raise circulating thyroid hormone levels, which stacks with levothyroxine and risks iatrogenic hyperthyroidism.
What to do
Avoid or monitor thyroid labs closely if combining.
How to fit both into one day
Ashwagandha lowers cortisol and is mildly sedating, so evening dosing suits it. Avoid with thyroid medication without lab monitoring.
Levothyroxine needs an empty stomach and gastric acid for full absorption. Take it 30-60 minutes before breakfast with plain water, and keep calcium, iron and coffee at least 4 hours away.
Putting Ashwagandha (KSM-66) in the evening and Levothyroxine in the morning satisfies the 0-hour separation without disrupting either one's absorption window.