The short answer
Not known in people. The only study we found was in mice, where a brahmi (Bacopa monnieri) leaf extract raised T4, a thyroid hormone, by 41%. If the same happened in people, brahmi could add to levothyroxine or work against antithyroid drugs such as carbimazole. Nobody has tested that.
We found no study of brahmi with any thyroid medicine. Levothyroxine has a narrow therapeutic index, so small changes can matter. If you take a thyroid medicine, tell your prescribing doctor before you start brahmi, and ask whether your TSH and T4 should be rechecked.
Levothyroxine is sold in India as Thyronorm and Eltroxin. Carbimazole is sold as Neo-Mercazole, methimazole as Methimez, and propylthiouracil as PTU.
At a glance
| What was seen | How it may work | Direction | Evidence |
|---|---|---|---|
| T4 raised by 41% in male mice[1] | Possible thyroid stimulation; not established | May add to levothyroxine; may work against carbimazole or methimazole | Animal |
No listing is not a clearance. A missing interaction here never means a combination is safe.
The evidence, study by study
Mouse study, 2002 Animal
Male mice were given leaf extracts of three medicinal plants, one of them Bacopa monnieri, and their thyroid hormones were measured. Bacopa raised T4 by 41%, and the authors suggest it stimulates the thyroid. No thyroid medicine was given, and a mouse result cannot tell us what happens in people.[1]
What your doctor may watch for
- TSH and T4, if your doctor thinks they should be rechecked after you start brahmi.[2]
- The levothyroxine label says it has a narrow therapeutic index, and that too much or too little can affect the heart and bones.[2]
What to tell your prescribing doctor
You can read this out, or show them this page:
“I am taking, or planning to take, brahmi (name of product, the Latin name on the pack, dose) along with my thyroid medicine. In mice, brahmi raised the thyroid hormone T4. Should my TSH and T4 be checked, and when?”
Withheld until review
Questions people ask
Related
Ashwagandha and thyroid medicines
Ashwagandha can raise thyroid hormone levels. That could add to levothyroxine, or work against antithyroid drugs.
ConditionUnderactive thyroid (hypothyroidism): what Ayurveda offers
One small trial found ashwagandha improved mildly raised TSH. No trial we found tested Ayurveda in place of levothyroxine. Do not stop it.
InteractionFenugreek (methi) and levothyroxine
Not tested in people. In mice and rats, methi seed extract lowered T3 and raised T4. Nobody has studied it with levothyroxine.
InteractionGuggulu and thyroid medicine (levothyroxine)
Guggul raised thyroid hormone in mice. The one human trial in people on levothyroxine used a multi-herb tablet and cannot show guggul's own effect.
Sources
- Kar A, Panda S, Bharti S. Relative efficacy of three medicinal plant extracts in the alteration of thyroid hormone concentrations in male mice. J Ethnopharmacol. 2002;81:281-285. PMID 12065164.
- Levothyroxine sodium tablets, US prescribing information (DailyMed, Proficient Rx).
- Walker EA, Pellegrini MV. Bacopa monnieri. StatPearls. Updated 17 March 2023.
- LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Bacopa monnieri. Updated 24 April 2024.
Updated 4 November 2026
Taking brahmi with other medicines? A vaidya can check your full list.
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