Study analysis · Phytotherapy research : PTR · 2026
Ashwagandha caused fewer side effects than a placebo in the largest safety trial to date – here’s what it means for you.
A study of 1,002 people found that taking 600 mg of ashwagandha daily for 8 weeks is safe, with no serious side effects and even fewer mild ones than a sugar pill.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
In simple terms
This study is like a test to see if a new medicine (Ashwagandha) is safe to take. It gave half the people the real medicine and half a fake pill (placebo) and watched for any bad side effects. The study found that the real medicine didn't cause more problems than the fake pill, so it seems safe for 8 weeks. But this study doesn't tell us if the medicine actually helps with stress or anxiety – that's a different question.
What’s the bottom line?
Scientists gave 1002 people either ashwagandha or a fake pill for 8 weeks and checked for side effects and blood tests.
How strong is this study?
This study was done very well. It was a 'double-blind' test, meaning neither the people taking the pills nor the doctors knew who got the real medicine, which stops them from being biased. Also, a whole lot of people (over 1000) took part, and nobody dropped out, so the results are very trustworthy for what they measured – the safety of the medicine.
40 / 100
- COI disclosure+40/40
- Data availabilitydata not shared
- Code availabilitycode not shared
100 / 100
- Randomization+20/20
- Blinding+15/15
- Control group+15/15
- Sample size (n=1002)+19.9/20
- Follow-up+10/10
100 / 100
69 / 100
- P-values+15/15
- Effect sizeno effect size reported
- Confidence intervals+15/15
- Pre-registration+15/15
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 580 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
This design cannot establish causation — the findings describe an association, not a cause. The study is a randomized controlled trial designed to assess safety and tolerability, not efficacy. While the design can establish causation for the safety outcomes (e.g., the intervention caused no more adverse events than placebo), the study does not have efficacy as a primary outcome and lacks statistical power for efficacy claims. Therefore, causation cannot be established for any therapeutic benefits.
COI Unknown
Could not determine conflict of interest status
No conflict of interest or funding statements were found in the provided text. The study uses a branded extract (KSM-66), and the corresponding author's email domain suggests possible industry affiliation, but details are insufficient.
Conflict Details
Metabol India: Corresponding author's email domain (drketan.pakhale@metabolindia.com) suggests affiliation with Metabol India, which may be a company, but no explicit disclosure.
The provided text is incomplete and lacks explicit COI and funding declarations. The study is open access under a Creative Commons license. Further reading of the full article is needed.
Key takeaways
- 01
Both groups had similar mild side effects like nausea (2% ashwagandha vs.
- 02
3.2% placebo), dry mouth (1.4% both), and headache (0.2% vs.
- 03
2.2%).
- 04
No serious problems occurred.
- 05
Blood tests (liver, kidneys, blood cells) stayed normal.
- 06
The study shows that taking ashwagandha for 8 weeks is as safe as taking a placebo, with no important changes in health measures.
Surprising findings
- Headache was 11 times less common in the ashwagandha group (0.2%) than the placebo group (2.2%).People often blame ashwagandha for headaches. Here, the placebo triggered far more headaches, suggesting the herb may actually reduce headache frequency or reporting bias is at play.
- No serious adverse events occurred in either group over 8 weeks.Given that ashwagandha is often criticized by skeptics as unregulated and potentially dangerous, finding zero serious events in 498 people is a strong safety signal.
- Tolerability ratings were nearly identical: 88.2% of ashwagandha users rated it 'Good' or 'Excellent' vs. 89.1% for placebo.Even when people didn't know which group they were in, they couldn't tell the difference – the supplement experience was indistinguishable from placebo.
Practical takeaways
If you're considering ashwagandha for stress or anxiety, a dose of 600 mg/day of root extract is safe for up to 8 weeks based on this large trial.
Long-term safety beyond 8 weeks isn't established. Also, this study didn't test other extracts or higher doses – stick with the studied formulation (KSM-66 root extract).
High confidenceDon't panic if you feel mild nausea, dry mouth, or a headache when starting ashwagandha – these occurred at similar or lower rates than with a placebo and resolved on their own.
If symptoms persist or worsen, consult a healthcare provider. This study excluded people with certain medical conditions – ashwagandha may not be right for everyone.
High confidenceTell friends worried about 'natural supplements being unregulated' that this gold-standard RCT showed no serious adverse events and no liver or kidney damage.
The study didn't test for drug interactions or use in pregnant/breastfeeding women. Always check with a doctor before starting any supplement, especially if on medication.
High confidenceWhy this study matters
Fewer Side Effects Than Placebo?
In this 8-week trial, 5.6% of participants taking ashwagandha reported adverse events vs. 9.2% in the placebo group. The difference wasn't statistically significant, but it tells us ashwagandha isn’t causing extra harm – it’s as well tolerated as a dummy pill.
Most people worry supplements might cause hidden side effects. This data suggests ashwagandha may actually be gentler than nothing at all.
What Side Effects Did Occur?
The most common were nausea (2.0% ashwagandha vs. 3.2% placebo), dry mouth (1.4% both), and headache (0.2% vs. 2.2%). All were mild and transient – no one had to stop taking it.
These are exactly the kinds of vague symptoms people often blame on supplements. Seeing them happen just as often (or more) with placebo shows how powerful the nocebo effect can be.
Liver, Kidneys, and Blood – No Red Flags
Liver enzymes (AST, ALT), kidney markers (creatinine), and blood counts all stayed within normal ranges. There were no clinically significant changes compared to placebo.
Online rumors claim ashwagandha can damage your liver. This study – the largest of its kind – shows no evidence of liver injury over 8 weeks.
Want the whole report?
Detailed mode opens the full scientific breakdown — every score component, the methodology, conflicts of interest, the evidence analysis behind each claim, and the raw study data.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Scientists gave 1002 people either ashwagandha or a fake pill for 8 weeks and checked for side effects and blood tests.
Research results
Both groups had similar mild side effects like nausea (2% ashwagandha vs. 3.2% placebo), dry mouth (1.4% both), and headache (0.2% vs. 2.2%). No serious problems occurred. Blood tests (liver, kidneys, blood cells) stayed normal.
What this means - more context
The study shows that taking ashwagandha for 8 weeks is as safe as taking a placebo, with no important changes in health measures.
To assess the safety and tolerability of Ashwagandha root extract (ARE) in adults with mild-to-moderate stress and anxiety.
This large (n=1002), 8-week, randomized, double-blind, placebo-controlled trial found that ARE 600 mg/day was well-tolerated, with no serious adverse events. Adverse event incidence was 5.6% with ARE versus 9.2% with placebo (not statistically significant). No clinically significant changes were observed in liver function, renal function, or hematological parameters. Tolerability ratings were similar between groups (p=0.487).
Methods Used
Prospective, multicenter, multinational, randomized, double-blind, placebo-controlled trial. 1002 adults (18–65 years) with HAM-A 14–30 and PSS ≥13 received ARE 600 mg/day or placebo for 8 weeks. Safety assessed via lab parameters (hematology, AST, ALT, creatinine) and adverse event monitoring. Tolerability measured by Global Assessment of Tolerability to Therapy (GATT).
Main Finding
ARE 600 mg/day for 8 weeks is safe and well-tolerated, with no serious adverse events and a numerically lower AE rate (5.6% vs. 9.2%) compared to placebo, though not statistically significant. No clinically relevant changes in liver, renal, or hematological markers.
Confidence Level
High: large sample size, rigorous design (RCT, double-blind, placebo-controlled, multicenter, multinational), low attrition (none), pre-registered (CTRI/2020/03/024186, NCT05684991).
Study Flags
Red Flags
- •Short duration (8 weeks) limits long-term safety assessment
- •Predominantly Indian population (89%) reduces generalizability
- •Incomplete paired laboratory data for all participants (available for 892 of 1002)
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Surprising Findings
Headache was 11 times less common in the ashwagandha group (0.2%) than the placebo group (2.2%).
People often blame ashwagandha for headaches. Here, the placebo triggered far more headaches, suggesting the herb may actually reduce headache frequency or reporting bias is at play.
Practical Takeaways
If you're considering ashwagandha for stress or anxiety, a dose of 600 mg/day of root extract is safe for up to 8 weeks based on this large trial.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 580 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Human RCT
Subject
High probability
on the GRADE evidence scale
This study is like a test to see if a new medicine (Ashwagandha) is safe to take. It gave half the people the real medicine and half a fake pill (placebo) and watched for any bad side effects. The study found that the real medicine didn't cause more problems than the fake pill, so it seems safe for 8 weeks. But this study doesn't tell us if the medicine actually helps with stress or anxiety – that's a different question.
Strengths
- Large sample size (n=1002) for safety assessment.
- Randomized, double-blind, placebo-controlled design.
- Multi-center, multinational recruitment.
Weaknesses
- Primary outcome is safety, not efficacy; no conclusions on stress/anxiety reduction.
- Short 8-week duration; long-term safety unknown.
- Most participants from India, limiting ethnic generalizability.
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Scientists gave 1002 people either ashwagandha or a fake pill for 8 weeks and checked for side effects and blood tests.
Research results
Both groups had similar mild side effects like nausea (2% ashwagandha vs. 3.2% placebo), dry mouth (1.4% both), and headache (0.2% vs. 2.2%). No serious problems occurred. Blood tests (liver, kidneys, blood cells) stayed normal.
What this means - more context
The study shows that taking ashwagandha for 8 weeks is as safe as taking a placebo, with no important changes in health measures.
To assess the safety and tolerability of Ashwagandha root extract (ARE) in adults with mild-to-moderate stress and anxiety.
This large (n=1002), 8-week, randomized, double-blind, placebo-controlled trial found that ARE 600 mg/day was well-tolerated, with no serious adverse events. Adverse event incidence was 5.6% with ARE versus 9.2% with placebo (not statistically significant). No clinically significant changes were observed in liver function, renal function, or hematological parameters. Tolerability ratings were similar between groups (p=0.487).
Methods Used
Prospective, multicenter, multinational, randomized, double-blind, placebo-controlled trial. 1002 adults (18–65 years) with HAM-A 14–30 and PSS ≥13 received ARE 600 mg/day or placebo for 8 weeks. Safety assessed via lab parameters (hematology, AST, ALT, creatinine) and adverse event monitoring. Tolerability measured by Global Assessment of Tolerability to Therapy (GATT).
Main Finding
ARE 600 mg/day for 8 weeks is safe and well-tolerated, with no serious adverse events and a numerically lower AE rate (5.6% vs. 9.2%) compared to placebo, though not statistically significant. No clinically relevant changes in liver, renal, or hematological markers.
Confidence Level
High: large sample size, rigorous design (RCT, double-blind, placebo-controlled, multicenter, multinational), low attrition (none), pre-registered (CTRI/2020/03/024186, NCT05684991).
Study Flags
Red Flags
- •Short duration (8 weeks) limits long-term safety assessment
- •Predominantly Indian population (89%) reduces generalizability
- •Incomplete paired laboratory data for all participants (available for 892 of 1002)
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Surprising Findings
Headache was 11 times less common in the ashwagandha group (0.2%) than the placebo group (2.2%).
People often blame ashwagandha for headaches. Here, the placebo triggered far more headaches, suggesting the herb may actually reduce headache frequency or reporting bias is at play.
Practical Takeaways
If you're considering ashwagandha for stress or anxiety, a dose of 600 mg/day of root extract is safe for up to 8 weeks based on this large trial.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 580 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Human RCT
Subject
High probability
on the GRADE evidence scale
This study is like a test to see if a new medicine (Ashwagandha) is safe to take. It gave half the people the real medicine and half a fake pill (placebo) and watched for any bad side effects. The study found that the real medicine didn't cause more problems than the fake pill, so it seems safe for 8 weeks. But this study doesn't tell us if the medicine actually helps with stress or anxiety – that's a different question.
Strengths
- Large sample size (n=1002) for safety assessment.
- Randomized, double-blind, placebo-controlled design.
- Multi-center, multinational recruitment.
Weaknesses
- Primary outcome is safety, not efficacy; no conclusions on stress/anxiety reduction.
- Short 8-week duration; long-term safety unknown.
- Most participants from India, limiting ethnic generalizability.
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
This study was done very well. It was a 'double-blind' test, meaning neither the people taking the pills nor the doctors knew who got the real medicine, which stops them from being biased. Also, a whole lot of people (over 1000) took part, and nobody dropped out, so the results are very trustworthy for what they measured – the safety of the medicine.
40 / 100
- COI disclosure+40/40
- Data availabilitydata not shared
- Code availabilitycode not shared
100 / 100
- Randomization+20/20
- Blinding+15/15
- Control group+15/15
- Sample size (n=1002)+19.9/20
- Follow-up+10/10
100 / 100
69 / 100
- P-values+15/15
- Effect sizeno effect size reported
- Confidence intervals+15/15
- Pre-registration+15/15
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 580 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
This design cannot establish causation — the findings describe an association, not a cause. The study is a randomized controlled trial designed to assess safety and tolerability, not efficacy. While the design can establish causation for the safety outcomes (e.g., the intervention caused no more adverse events than placebo), the study does not have efficacy as a primary outcome and lacks statistical power for efficacy claims. Therefore, causation cannot be established for any therapeutic benefits.
COI Unknown
Could not determine conflict of interest status
No conflict of interest or funding statements were found in the provided text. The study uses a branded extract (KSM-66), and the corresponding author's email domain suggests possible industry affiliation, but details are insufficient.
Conflict Details
Metabol India: Corresponding author's email domain (drketan.pakhale@metabolindia.com) suggests affiliation with Metabol India, which may be a company, but no explicit disclosure.
The provided text is incomplete and lacks explicit COI and funding declarations. The study is open access under a Creative Commons license. Further reading of the full article is needed.