Ashwagandha and Levothyroxine
Supplement–drug interaction evidence from the TruthStack database.
| Severity | MODERATE |
|---|---|
| Evidence Tier | Moderate |
| Interaction Type | ANTAGONISTIC |
| Mechanism | PHARMACODYNAMIC |
| Last Reviewed | 2026-02-24 |
Summary
Ashwagandha has demonstrated thyroid-stimulating activity — increasing serum T3 and T4 in subclinical hypothyroidism trials. In patients on levothyroxine, ashwagandha may alter thyroid hormone levels and require dose adjustment. FAERS: 36 reports. Monitor thyroid panel.
CYP Enzyme Profiles
Published CYP enzyme data for compounds in this interaction:
Levothyroxine: CYP3A4 substrate (weak)
Shared Pharmacodynamic Endpoints
Both compounds influence the same physiological endpoints in the same direction:
| Endpoint | Direction | Ashwagandha | Levothyroxine |
|---|---|---|---|
| THYROID | INCREASE | MODERATE | STRONG |
Cumulative effect on shared endpoints may exceed individual compound profiles. This is relevant to discussion with a prescribing clinician.
API Reference
GET https://api.truthstack.co/v1/check?c1=ashwagandha&c2=levothyroxine
Open, unauthenticated. Returns JSON. Developer documentation
Sources
Primary: 28829155
Related Interactions
What this page is and is not. TruthStack is an informational reference database that describes published pharmacological findings. It does not provide medical advice, diagnosis, or treatment recommendations. The information on this page reflects flags in our database and should not replace consultation with a qualified healthcare provider. Always discuss supplement-drug combinations with your prescriber or pharmacist.