- The question
- Does ashwagandha root extract change TSH, T3 and T4 in adults with subclinical hypothyroidism, a raised TSH without obvious symptoms of an underactive thyroid?
- Who was studied
- 50 adults aged 18 to 50 with a TSH between 4.5 and 10, at a hospital in Varanasi. 25 were placed in each group.
- What they took
- Ashwagandha root extract, 600 mg a day, or a starch placebo, for eight weeks. Neither the participants nor the researchers knew who had which.
- What happened
- After eight weeks, TSH, T3 and T4 had all improved significantly more with ashwagandha than with placebo (P<0.001, P=0.0031 and P=0.0096). Four people withdrew before the second visit, two from each group. The abstract does not say how far each test moved.[1]
- How strong is this
- Randomised and double-blind, but the authors call it a pilot study. With 50 people over eight weeks, it shows a signal worth testing, not a treatment.
The limits
- A pilot study: 50 people at one hospital, for eight weeks.
- The summary gives P values but not the size of the change in TSH, T3 or T4, so the size of the effect is not known from it.
- The trial measured blood tests only. It did not show that people felt better, or that later thyroid disease was prevented.
- It tested people with a mildly raised TSH. It did not test ashwagandha in full hypothyroidism, or alongside levothyroxine.
- Liver injury has been reported with supplements containing ashwagandha. An eight-week trial in 50 people does not settle that risk.
Who paid for it
Not given in the abstract we read. We have not confirmed who paid for the trial.
Questions people ask
Can ashwagandha replace my thyroid tablet?
This trial cannot show that. It tested 50 people with a mildly raised TSH for eight weeks. It did not test replacing levothyroxine, or adding ashwagandha to it. If you take a thyroid medicine, tell your prescribing doctor before you start ashwagandha.[1]
Does this apply to the ashwagandha I buy?
The trial used a root extract. Powders, churnas and multi-herb products were not tested, so the result cannot simply be carried over to them.[1]
Can ashwagandha harm the liver?
Liver injury has been reported. A 2020 case series from Iceland and the US described five people with liver injury put down to supplements containing ashwagandha. Case reports cannot show how often this happens, and an eight-week trial in 50 people cannot settle it.[2][3]
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.
EvidenceDoes ashwagandha reduce stress?
One small placebo-controlled trial found ashwagandha root extract lowered stress scores and cortisol over 60 days. Promising, not settled.
Sources
- Sharma AK, Basu I, Singh S. Efficacy and safety of ashwagandha root extract in subclinical hypothyroid patients: a double-blind, randomized placebo-controlled trial. J Altern Complement Med. 2018;24(3):243-248. PMID 28829155.
- Björnsson HK, Björnsson ES, Avula B, Khan IA, Jonasson JG, Ghabril M, Hayashi PH, Navarro V. Ashwagandha-induced liver injury: a case series from Iceland and the US Drug-Induced Liver Injury Network. Liver Int. 2020;40(4):825-829. PMID 31991029.
- LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Ashwagandha. Not yet checked by us: the page returned a reCAPTCHA challenge.Not yet checked against the original
Updated 4 November 2026
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