The short answer
Not known in people. We found no study in people that tested berberine with levothyroxine. The two related studies were in rats given large doses of thyroid hormone, and both used isolated berberine, not daruharidra (daru haldi) or a classical medicine. In those rats, berberine lessened the heart enlargement and diarrhoea that the excess hormone caused.
Rat studies like these cannot tell us how levothyroxine is absorbed in people, or what happens to TSH. Levothyroxine has a narrow therapeutic index, so small changes can matter. If you take levothyroxine, tell your prescribing doctor before you start berberine, and ask whether your TSH should be rechecked.
Levothyroxine is sold in India as Thyronorm and Eltroxin.
At a glance
| What was seen | How it may work | Direction | Evidence |
|---|---|---|---|
| Less heart enlargement in rats given excess thyroxine (isolated berberine)[1] | Lower calcineurin activity in heart muscle | Effect on levothyroxine treatment not known | Animal |
| Less diarrhoea and lower gut hormones in hyperthyroid rats (isolated berberine)[2] | Not established | Effect on levothyroxine absorption not tested | Animal |
No listing is not a clearance. A missing interaction here never means a combination is safe.
The evidence, study by study
Rat study, 2004 Animal
Twenty-four rats were split into three groups. Two groups were injected with L-thyroxine for 10 days to enlarge the heart, and one of these was also given berberine by mouth. Heart size measures and calcineurin activity were lower with berberine than with thyroxine alone. The hormone was injected at a high dose, so this says nothing about levothyroxine tablets in people.[1]
Rat study, 2009 Animal
Rats were made hyperthyroid, which gave them diarrhoea, and some were then given berberine. Berberine reduced the rise in two gut hormones, motilin and gastrin, and the wet stools. The study did not test absorption of any thyroid medicine.[2]
What your doctor may watch for
- TSH and free T4, on the schedule your thyroid doctor sets.[3]
- The levothyroxine label says it has a narrow therapeutic index, so small changes in absorption or dose can matter.[3]
What to tell your prescribing doctor
You can read this out, or show them this page:
“I am taking, or planning to take, berberine (name of product, how much berberine it contains, dose) along with levothyroxine. It has not been studied with levothyroxine in people. Should my TSH be rechecked after I start, and when?”
Withheld until review
Questions people ask
Does berberine interfere with thyroid medication?
Nobody knows yet. No study has measured levothyroxine levels or TSH in people taking berberine, and the rat study of the heart used injected thyroid hormone at a high dose.[1][2]
Should I keep a gap between berberine and levothyroxine?
No study has tested a gap between the two. The spacing advice on the levothyroxine label is for other named products, not berberine, so ask your prescribing doctor.[3]
Is daruharidra the same as berberine?
No. Berberine is one compound found in daruharidra (Berberis aristata, also called Indian barberry or tree turmeric) and in plants such as barberry, goldthread and goldenseal. How much berberine a daruharidra powder or classical medicine gives is not known from these studies.[4]
Related
Berberine and metformin
In one small trial, a 97% berberine tablet lowered sugar further when added to metformin. In rats, berberine changed where metformin goes in the body.
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.
InteractionAshwagandha and thyroid medicines
Ashwagandha can raise thyroid hormone levels. That could add to levothyroxine, or work against antithyroid drugs.
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.
Sources
- Yang J, Zhou ZY, Xu JG. [Protective effect of berberine on cardiac hypertrophy induced by L-thyroxine in rats]. Sichuan Da Xue Xue Bao Yi Xue Ban. 2004;35(2):223-225. PMID 15071923.
- Cheng ZF, Zhang YQ, Liu FC. Berberine against gastrointestinal peptides elevation and mucous secretion in hyperthyroid diarrheic rats. Regul Pept. 2009;155(1-3):145-149. PMID 19323986.
- Levothyroxine sodium tablets, US prescribing information (DailyMed, Proficient Rx).
- Memorial Sloan Kettering Cancer Center. About Herbs: Berberine.
Updated 4 November 2026
Taking berberine with other medicines? A vaidya can check your full list.
Medicine Check · ₹299