Supplement
Ashwagandha (standardized root extract)
Cortisol and stress or anxiety scores in stressed adults (pooled analyses disagree on perceived stress); sleep in adults with insomnia; a strength signal from two maker-funded trials that a 2026 meta-analysis A study that pools the numbers from several trials into one combined estimate. rates fragile.
Ashwagandha is an herb long used in India. Small studies tested a root extract in stressed adults for about two months. People taking it had lower levels of the stress hormone cortisol than people taking a dummy pill. Their scores on stress and anxiety questionnaires also fell in some studies but not in others. In the main studies, the extract was supplied or paid for by its maker. Rare cases of liver injury have been reported, and it can raise thyroid hormone levels.
A letter describes the human evidence, not the product, the manufacturer, or the ingredient's worth.
See the full evidence record →Who responds: this record's trial reading reports no subgroup that identifies who responds.
Funding: All four trials this Grade B rests on were funded by industry: Chandrasekhar 2012 (PMID PubMed ID: the permanent number the US National Library of Medicine gives a published paper. Each one links to that paper's record on PubMed. 23439798) by the maker of the studied product, who donated it; Wankhede 2015 (PMID 26609282) by the maker of the studied product, who donated it; Lopresti 2019 (PMID 31517876) by the maker of the product it tested; Ziegenfuss 2018 (PMID 30463324) by the maker of the product it tested. The funder's role in design and analysis is not stated here, because the full trial reports could not be read. The letter is what the trials support under the grading rules; the funding is stated here so it can be weighed alongside it.
Cortisol and stress or anxiety scores in stressed adults; pooled analyses disagree on perceived stress. No cited trial measured thyroid.
A grade describes the intervention that was tested. Where the product on the shelf differs from it, this says so.
How this letter has changed · latest: October 2026 · Corrected
The B rests on Langade et al. (Cureus, 2019; PMID 31728244) and a five-trial meta-analysis of randomized sleep trials (Cheah et al., PLoS One, 2021; PMID 34559859). Pooled randomized evidence is replication The same finding reproduced by a separate research group. A result seen once can be chance or bias; a replicated one is harder to explain away. under the written rule; what the pooling does not show is a second trial of the same extract at the same dose, which the record states and which is not what the flag means. Flag removed, letter unchanged. Applied the written grade definition under the editor's standing instruction of October 2026 (Arnold Sandlow, D.C.).PMID 31728244 PMID 34559859
The best-use line claimed sleep quality with no sleep trial cited; Cheah 2021 (PMID 34559859) and Langade 2021 (PMID 32818573) now carry it. The ref treated two different extracts as one and overstated Lopresti 2019 (PMID 31517876): HAM-A and cortisol fell, the DASS-21 did not reach significance, testosterone did not differ from placebo An inactive substitute made to look like the real treatment, so participants cannot tell which one they received.; corrected. The strength signal is no longer called single-trial: Ziegenfuss 2018 (PMID 30463324) is added with its maker funding, and Lee 2026 (PMID 42738987) rates the pooled effect fragile. Albalawi 2025 (PMID 40746175), null on perceived stress, and Arumugam 2024 (PMID 39348746), positive, sit side by side. Björnsson 2020 (PMID 31991029), cholestatic liver injury cases, is added. Letter unchanged.PMID 34559859 PMID 32818573 PMID 31517876 PMID 30463324 PMID 42738987 PMID 40746175 PMID 39348746 PMID 31991029
Funding stated beside the letter. All three trials behind the Grade B were run with the extract maker's money or product: the standardized root extract supplied by its maker in Chandrasekhar 2012 (PMID 23439798) and Wankhede 2015 (PMID 26609282), and Lopresti 2019 (PMID 31517876) funded by the maker of the extract it tested. Letter unchanged.PMID 23439798 PMID 26609282 PMID 31517876
Every change to a letter on this site is dated and published. The full evidence log →
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EBL earns no commission on any supplement it grades. A purchase made through the dispensary link below pays EBL nothing, the practitioner discount goes to you in full. The dispensary is Fullscript, a practitioner dispensary, and many of the professional-grade brands in it are sold mainly through practitioners rather than in health food stores. Grades are assigned by published rubric before any commercial relationship exists and are never influenced by one. Full disclosure.
300–600 mg/day of a standardized extract.
The trials used standardized extracts, either full-spectrum root or root plus leaf, with a stated withanolide content. Generic ashwagandha without a stated standardization lacks that data.
Timing differed between the cited trials: one capsule once daily after dinner (PMID 31517876), one capsule twice a day after food (PMID 23439798), and one capsule on waking and one shortly before bed (PMID 26609282).
Checked against the full published reports. What the cited trials did, not a schedule. Every supplement, by trial timing →
How to buy this: quality criteria, not a brand
300–600mg/day of a standardized extract; evening dosing for sleep.
A standardized extract, either full-spectrum root or root plus leaf, as used in the trials.
A stated withanolide percentage on the label, and any USP or NSF third-party seal.
Generic “ashwagandha root powder”; unnamed extract; no standardization data.
The grade and these criteria are set only from human trials. Any purchase link is convenience and does not affect the grade.
Liver disease, or any current unexplained rise in liver enzymes. Ashwagandha-induced liver injury is documented, typically appearing weeks to months after starting and usually resolving on stopping. Thyroid conditions: ashwagandha can raise T3 and T4. Autoimmune disease, on the immune-stimulating effect. Pregnancy.
Thyroid medication: additive, since ashwagandha raises thyroid hormone itself. Immunosuppressants: opposed, on the immune-stimulating effect. Sedatives and benzodiazepines: additive CNS depression. Any other hepatotoxic drug, on the liver-injury signal above.
Ashwagandha-induced liver injury is documented. Liver injury attributed to ashwagandha has been described in a case series drawn from Iceland and the US Drug-Induced Liver Injury Network, and characterized further in a later scoping review. Bjornsson et al. (Liver International, 2020; PMID 31991029): ashwagandha-induced liver injury, a case series from Iceland and the US Drug-Induced Liver Injury Network. McIntyre et al. (Cureus, 2026; PMID 42367407): scoping review of the clinical characteristics and safety considerations of ashwagandha-associated liver injury.
Salivary/serum cortisol, sleep quality (ISI scale), testosterone (if relevant), thyroid panel if pre-existing concern
Primary evidenceTen papers, each linked to its PubMed record.
Stress: Chandrasekhar et al. (Indian J Psychol Med, 2012; PMID 23439798): 64 adults, a full-spectrum root extract at 300 mg twice daily (600 mg/day) for 60 days; all stress scales and serum cortisol fell versus placebo. Lopresti et al. (Medicine (Baltimore), 2019; PMID 31517876): 60 adults, a DIFFERENT standardized extract at 240 mg/day, below this record's dose range, for 60 days; HAM-A fell (P = .040) and morning cortisol fell, but the DASS-21 did not differ significantly from placebo (P = .096) and the testosterone change was not significant versus placebo. Pooled: Arumugam et al. (Explore, 2024; PMID 39348746), 9 trials, 558 patients, Perceived Stress Scale, HAM-A and cortisol all improved; Albalawi et al. (Nutr Health, 2025; PMID 40746175), 7 trials on cortisol and 6 on perceived stress, cortisol fell 1.16 micrograms/dL but the Perceived Stress Scale did not change (SMD -0.36, P = 0.40). Sleep: Cheah et al. (PLoS One, 2021; PMID 34559859), 5 trials, 400 participants, small effect on sleep (SMD -0.59), larger in diagnosed insomnia, at 600 mg/day or more and 8 weeks or longer; Langade et al. (J Ethnopharmacol, 2021; PMID 32818573), 80 adults, sleep onset latency and sleep quality improved, more in those with insomnia. Strength: Wankhede et al. (J Int Soc Sports Nutr, 2015; PMID 26609282), 57 men, strength and testosterone rose; Ziegenfuss et al. (Nutrients, 2018; PMID 30463324), 38 men, a root-and-leaf extract at 500 mg/day, squat and bench press gains larger than placebo, funded by that extract's maker; Lee et al. (Nutrients, 2026; PMID 42738987), meta-analysis of the resistance-training trials, found the strength effect lost significance under conservative adjustment and rated the certainty low. Safety: Björnsson et al. (Liver Int, 2020; PMID 31991029), five cases of cholestatic liver injury with jaundice attributed to ashwagandha supplements in Iceland and the US Drug-Induced Liver Injury Network, resolving in 1 to 5 months. Grade B: replicated randomized evidence on self-reported and biomarker A measurable sign in the body, such as a blood test value, used to track a condition or the effect of a treatment. endpoints The outcome a trial measures to decide whether the treatment worked, such as heart attacks, blood pressure or a symptom score., with the pooled analyses split on perceived stress. Funding: the extract in Chandrasekhar et al. and Wankhede et al. was supplied by its maker; Lopresti et al. was funded by the maker of the extract it tested, which also supplied it, with the two Indian principal investigators declaring no competing interest and the first author declaring past study funding from the same company; Ziegenfuss et al. was funded by its extract's maker. No trial behind the letter was run without an extract maker's money or product.
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(ashwagandha[tiab] OR Withania somnifera[tiab]) AND (stress[tiab] OR anxiety[tiab] OR sleep[tiab] OR strength[tiab] OR cortisol[tiab]) AND (randomized controlled trial[pt] OR meta-analysis[pt]) AND humans[mesh]Grades move when new trials publish. A free monthly email lists every grade EBL moved, with the reason and the trial behind it: the sign-up is on the Evidence Log →