Drug interactions
ashwagandha + levothyroxine
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Overview
Ashwagandha may increase thyroid hormone levels, leading to additive effects with levothyroxine and risk of hyperthyroidism/thyrotoxicosis (e.g., palpitations, tachyarrhythmias).
Mechanism of action
Probable pharmacodynamic interaction: ashwagandha may increase T3/T4 or stimulate thyroid function; additive thyromimetic effect with levothyroxine.
Clinical management
Consider avoiding the combination. If used, monitor TSH and free T4 about 4–6 weeks after initiation, discontinuation, or dose changes; counsel on hyperthyroid symptoms; adjust levothyroxine dose or stop ashwagandha if TSH is suppressed or symptoms occur.
Drug reference
References
- Ashwagandha (Withania somnifera): Monograph — Lexicomp
- Ashwagandha (Withania somnifera): Drug information — UpToDate
Frequently asked questions
Can I take ashwagandha with levothyroxine?
The interaction is rated: Moderate. Ashwagandha may increase thyroid hormone levels, leading to additive effects with levothyroxine and risk of hyperthyroidism/thyrotoxicosis (e.g., palpitations, tachyarrhythmias).
How serious is the interaction between ashwagandha and levothyroxine?
The interaction is rated: Moderate. Evidence level: Moderate.
How is the interaction between ashwagandha and levothyroxine managed?
Consider avoiding the combination. If used, monitor TSH and free T4 about 4–6 weeks after initiation, discontinuation, or dose changes; counsel on hyperthyroid symptoms; adjust levothyroxine dose or stop ashwagandha if TSH is suppressed or symptoms occur.
Why do ashwagandha and levothyroxine interact?
Probable pharmacodynamic interaction: ashwagandha may increase T3/T4 or stimulate thyroid function; additive thyromimetic effect with levothyroxine.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.