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Pooled review (meta-analysis)

Pooled review of 23 trials, 1,706 adults: lower cortisol, higher serotonin with ashwagandha

Fornalik and colleagues · Planta medica · 2026

Original title: Hormonal Modulation with Withania somnifera: Systematic Review and Meta-Analysis of Randomized-controlled Trials.

Under review. A person has not yet checked this summary against the paper. It is written from the PubMed abstract. Until a person checks it, search engines are asked not to list this page.

What the study found

Points to benefit

Ashwagandha lowered cortisol (SMD =- 1.18, p < 0.04) and raised serotonin (MD = 31.75 ng/ml, p < 0.01). It did not change TSH or T3. Stress or anxiety scores are not reported in the abstract.

The study at a glance

Type of study
Pooled review (meta-analysis)
Who or what was studied
23 studies, 1,706 people · adults in 23 placebo-controlled trials
What was tested
Oral ashwagandha compared with placebo, looking at hormone levels
What it measured
Lab tests or markers
Who has a stake
No stake declared
No competing interests declared.
Journal
Planta medica, 2026
Source
PubMed record 41740946. This page is based on the abstract only.

How much this study counts

  • ✓Pools the results of 23 studies with 1,706 people.
  • •A pooled review is only as strong as the studies it pools.
  • –Measured lab tests or markers, which stand in for stress, anxiety and cortisol. A better marker does not always mean better health.
  • ✓No competing interests declared.
  • •Summarized from the PubMed abstract only. The full paper may hold details the abstract leaves out.

✓ Strength– Limit• Note

These points come from fixed rules about the type of study, its size and length, what it measured, and who has a stake. Every study on Digestery gets the same rules.

Where this study sits

This paper is not on the ladder. It is a pooled review (meta-analysis), and reviews and opinion pieces discuss studies that are already counted on the steps below.

↑ Stronger evidence

  1. Trials in people: stress and anxiety

    9

    7 benefit, 2 no difference

  2. Trials in people: other measures

    6

    3 benefit, 1 mixed, 1 no difference, 1 no direction

  3. Trials in people: lab tests or safety

    1

    1 benefit

  4. Population studies

    1

    1 benefit

  5. Blood levels and genes

    0

    None among the papers we read.

↓ Weaker evidence

  • Points to benefit
  • Mixed
  • No difference
  • No direction
  • Points to harm

How it fits with the other research

The short answer to “Does ashwagandha reduce stress and anxiety?”

Possibly, but the evidence is weak.

Confidence: low. Based on 24 on-topic papers.

Read the full answer
  • Quoted in “What we found”: Twenty-three trials with 1706 people, pooled in one review, showed lower cortisol, a stress hormone, with ashwagandha. That review reports no stress or anxiety scores.
  • Part of the finding “Cortisol often falls, but not in every trial”.
  • Summed up in “What reviews found”: Pooled twenty-three placebo-controlled trials with 1706 people on hormone levels. Ashwagandha lowered cortisol and raised serotonin, with no effect on TSH or T3. It reports no stress or anxiety scores and notes the trials varied.
  • Marked as a key paper in the research timeline: Largest pooled review: 1706 people, cortisol lowered.

Other reviews on this question

See all 24 studies on this question

How this page was made

Label

First read of the abstract
Claude Sonnet
Independent second read
Claude Haiku
Differences settled
The two reads agreed on every checked field. Claude Opus 5.5.
Headline
Claude Sonnet, from the checked study record. A script checked its numbers and wording.
Numbers
Checked against the abstract by a script
“How much this study counts”
Fixed rules, the same for every study
Source check by a person
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