Primary Research · 2018
Efficacy and Safety of Ashwagandha Root Extract in Subclinical Hypothyroid Patients: A Double-Blind, Randomized Placebo-Controlled Trial
Sharma et al. · J Altern Complement Med, 2018
Key finding
TSH decreased significantly (p<0.001); T3 increased significantly (p=0.0031); T4 increased significantly (p=0.0096). Direction of effect consistent with thyroid-stimulating action of ashwagandha.
Abstract
PubMed · PMID 28829155 →BACKGROUND: Subclinical hypothyroidism, a thyroid disorder without obvious symptoms of thyroid deficiency, occurs in 3%-8% of the global population. Ashwagandha [Withania somnifera (L.) Dunal], a traditional medicine in Ayurveda, is often prescribed for thyroid dysfunctions. OBJECTIVE: This pilot study was designed to evaluate the efficacy and safety of ashwagandha root extract in subclinical hypothyroid patients. DESIGN, SETTING, AND PARTICIPANTS: A prospective, randomized, double-blind, single-center placebo-controlled study was performed at Sudbhawana Hospital, Varanasi, India between May 2016 and September 2016. Fifty subjects with elevated serum thyroid stimulating hormone (TSH) levels (4.5-10 μIU/L) aged between 18 and 50 were randomized in either treatment (n = 25) or placebo (n = 25) groups for an 8-week treatment period. INTERVENTIONS: Ashwagandha root extract (600 mg daily) or starch as placebo. Efficacy Variables: Serum TSH, serum triiodothyronine (T3), and thyroxine (T4) levels. RESULTS: A total of four subjects (two from each group) withdrew their consent before the second visit. Eight weeks of treatment with ashwagandha improved serum TSH (p < 0.001), T3 (p = 0.0031), and T4 (p = 0.0096) levels significantly compared to placebo. Ashwagandha treatment effectively normalized the serum thyroid indices during the 8-week treatment period in a significant manner (time-effects: TSH [p < 0.001], T3 [p < 0.001], and T4 [p < 0.001]). Four subjects (8%) (ashwagandha: 1[4%]; Placebo: 3[12%]) out of 50 reported few mild and temporary adverse effects during this study. CONCLUSION: Treatment with ashwagandha may be beneficial for normalizing thyroid indices in subclinical hypothyroid patients.
Abstract sourced from PubMed, a database of the U.S. National Library of Medicine. Displayed in the authors’ own words for context; our critique is in the sections below.
Read the full paper
How to read a study like this
The same questions worth asking about any research paper, not just this one. Worth a minute even if you trust the grade.
Who was studied, and do you resemble them?
Supplement effects often depend on baseline status. Vitamin D helps people who are deficient; iron helps people who are anemic. A result in people unlike you may not apply to you.
What was measured, and does it matter in daily life?
A study that shows a blood marker moved isn't the same as a study that shows people felt or functioned better. Ask what the outcome means in practice.
How large was the effect — not just whether it was significant.
'Statistically significant' only means the effect is unlikely to be zero. It doesn't tell you the effect is large enough to notice. Look for effect sizes, not just p-values.
Who paid for the trial, and what did they stand to gain?
Industry-funded trials are several times more likely to report positive results than independent ones. It's not usually fraud — it's subtle design and reporting choices. Weight accordingly.
Has anyone else replicated this?
Single positive trials are hypotheses. Replication by independent groups is what turns a hypothesis into reliable evidence. If the only positive trial is the one you're reading, wait.
Does the dose in the trial match what's being sold?
Supplement marketing routinely cites trials that used 5–10× the dose in the product. If the effective dose was 2 g/day and the capsule has 200 mg, expect roughly no effect.
About this page
Formulate maintains a registry of clinical studies cited across its guides and evidence grades. This page links the study metadata to the content that cites it — one canonical entry per landmark study.
The full citation chain is public so readers can verify claims without hunting through individual guide pages. Browse all cited studies →
Note: Study summaries on this page are editorial interpretations of the research. Always consult the primary source before drawing clinical conclusions.