Ashwagandha vs Rhodiola for Stress: One Has the Meta-Analyses, the Other Has a Handful of Short Trials
Both are sold as adaptogens for frazzled days. Ashwagandha has pooled trials showing lower stress scores, with low certainty; rhodiola rests on a few small, short studies. Safety and drug interactions differ too.
By Kymata Health Editorial Published Last checked
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Key takeaways
From 8 sources- Ashwagandha lowered perceived stress versus placebo in a meta-analysis of 12 trials with 1,002 adults, but the trials varied widely and certainty was low1.
- Rhodiola's stress evidence is two small trials: 14 days in 80 mildly anxious adults with no placebo group, and 28 days in 60 adults with stress-related burnout23.
- NIH's Office of Dietary Supplements says ashwagandha appears well tolerated for up to about 3 months and its long-term safety is not known; NCCIH calls rhodiola possibly safe for up to 12 weeks48.
- Rare ashwagandha liver injury has been reported: in a 5-case series, jaundice appeared 2 to 12 weeks after starting5.
- Rhodiola cut the activity of CYP2C9, an enzyme that clears drugs such as losartan, by 21% in a 14-day study6.
What this article covers
2 evidence profilesThe evidence, graded
Pulled from the trial tables in our evidence profiles. Grades follow our evidence-grading policy.
Graded findings
4 rows- BGrade BPerceived stressImproved Stress (SMD -1.75) and anxiety (SMD -1.55) fell versus placebo. Heterogeneity was very high (I² 83–94%) and certainty of evidence was low.Ashwagandha · Meta-analysis · n=1,002 · 2022 · PMID 36017529
- BGrade BCortisolImproved Cortisol fell by 1.16 µg/dL versus placebo (95% CI -1.64 to -0.69). Perceived stress did not change significantly (SMD -0.355; 95% CI -1.188 to 0.47). Risk of bias was generally moderate.Ashwagandha · Meta-analysis · n=488 · 2025 · PMID 40746175
- DGrade DSelf-reported anxiety, stress and moodImproved Self-reported anxiety, stress, anger, confusion and depression scores fell and total mood improved versus no treatment; cognitive performance did not differ.Rhodiola rosea · RCT · n=80 · 2015 · PMID 26502953
- DGrade DFatigue and attention scoresImproved Both groups improved (placebo effect), but SHR-5 beat placebo on a burnout scale and several attention measures and changed the cortisol response to waking. No serious side effects attributed to the extract were reported.Rhodiola rosea · RCT · n=60 · 2009 · PMID 19016404
Where these trials agree: Ashwagandha and stress, counted row by row in the Consensus finder.
Ashwagandha: pooled trials, low certainty
A 2022 meta-analysis pooled 12 randomized trials with 1,002 adults aged 25 to 481. Stress and anxiety scores fell more with ashwagandha than placebo, and a dose-response analysis favored 300 to 600 mg a day for stress1. The trials differed a lot from each other and the authors rated certainty as low1.
Single trials add detail. In 60 stressed but healthy adults, 240 mg a day of a root-and-leaf extract for 60 days lowered morning cortisol more than placebo7. Extracts differ in plant part and withanolide content, so a dose from one trial does not transfer to another product4.
Rhodiola: promising, thin
In 80 mildly anxious adults, 200 mg of rhodiola twice a day for 14 days lowered self-reported anxiety, stress and low-mood scores compared with no treatment2. There was no placebo group, and the authors say cause and effect cannot be established2.
In 60 adults with stress-related fatigue, or burnout, 576 mg a day of the SHR-5 extract for 28 days beat placebo on a burnout scale and several attention measures, though both groups improved3. NCCIH concludes there is not enough reliable evidence that rhodiola helps any health purpose8.
Safety and interactions differ
Ashwagandha appears well tolerated in trials of up to about 3 months, according to NIH's Office of Dietary Supplements, but its long-term safety is not known4. Rare cases of liver injury have been reported; in a 5-case series, jaundice and other symptoms appeared 2 to 12 weeks after starting, and liver tests returned to normal within 1 to 5 months in the four patients followed up5. ODS also lists possible interactions with thyroid, diabetes, blood pressure, immunosuppressant and sedative medicines4.
NCCIH describes rhodiola as possibly safe for up to 12 weeks, with side effects that may include dizziness, headache and insomnia, and notes little is known about its safety in pregnancy or breastfeeding8. In a 14-day study in 13 healthy volunteers, rhodiola cut CYP2C9 activity by 21%, measured with the blood pressure drug losartan6.
Which one fits you
- Want the option with more trials behind it: ashwagandha, with low-certainty pooled evidence for lower stress scores1.
- Have a thyroid or liver condition, or take thyroid, diabetes or blood pressure medicine: ask your clinician before ashwagandha45.
- Take losartan, warfarin or other drugs cleared by CYP2C9: ask your pharmacist before rhodiola6.
- Are pregnant or breastfeeding: safety data for both are thin, so check with your clinician first48.
Quick answers
Common questions
3 answersHow long does rhodiola take to work for stress?
Can I take ashwagandha and rhodiola together?
Is it safe to take ashwagandha every day?
In trials, daily use appeared well tolerated for up to about 3 months, according to NIH's Office of Dietary Supplements; its long-term safety is not known4.
Keep reading
Full evidence profiles
Every graded study, studied doses, interactions and safetyRelated articles
4 articles- ArticleAshwagandha for Stress and Sleep: What the Trials Found, and Why the Results Vary So MuchDoes ashwagandha help with stress and sleep?
- ArticleAshwagandha for Testosterone: What the Trials Show (About 57 ng/dL, With Big Caveats)Does ashwagandha raise testosterone, and by how much?
- ArticleAshwagandha Interactions: Thyroid Medicine, Sedatives, SSRIs, Alcohol, Magnesium and L-TheanineWhat does ashwagandha interact with?
- ArticleAshwagandha Side Effects: The Liver, Thyroid and Pregnancy Warnings Behind Denmark’s BanWhat are the side effects of ashwagandha?
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7 products Paid links · we earn a commission- Quick pickMomentousMomentous Ashwagandha, 60 capsulesWe use this brand at home. What we useSubscribe & save 25%
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1 capsule: 300 mg NooGandha ashwagandha extract (standardized to 3.5% withanolides); 60 servings
$24.99one-time$18.74subscribeChecked Oct 15, 2026 - HerbsProNOW Foods KSM-66 Ashwagandha, 90 Veg Caps
1 veg capsule: 600 mg organic KSM-66 ashwagandha root extract
$18.41one-timeChecked Oct 14, 2026 - Botanic ChoiceBotanic Choice Ashwagandha Extract, 90 capsules
1 vege capsule: 450 mg ashwagandha root extract (1.5% withanolides, 6.75 mg); label directions 1 capsule 1 to 3 times daily with a meal
$24.00one-timeChecked Oct 12, 2026 - Physician’s ChoicePhysician’s Choice KSM-66 Ashwagandha (60 capsules)
2 capsules: 1,000 mg per serving as listed by the brand, from organic KSM-66 ashwagandha root extract (standardized to 5% withanolides) with organic black pepper extract; 30 servings
$29.97one-timeChecked Oct 20, 2026 - Dr. TobiasDr. Tobias Ashwagandha with Black Pepper (60 capsules)
Per serving: 1,300 mg organic ashwagandha root extract with 10 mg organic black pepper; 60 capsules, a 30-day supply
$21.99one-timeChecked Oct 14, 2026 - GoliGoli Ashwagandha Gummies, 60 gummies
1 gummy: 150 mg KSM-66 ashwagandha root extract and 12.5 mcg vitamin D (as ergocalciferol); label suggests 2 gummies twice daily
$15.98one-timeChecked Oct 15, 2026 - Renue by ScienceRenue by Science LIPO Ashwagandha, liposomal capsules (90)Subscribe & Save 10%
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1 capsule: 200 mg ashwagandha (Withania somnifera) root extract; 90 servings
$29.95one-time$26.96subscribeChecked Oct 15, 2026
References
8 sources. Numbers in the text link here.
Sources cited in this article
8 sources- 1Does Ashwagandha supplementation have a beneficial effect on the management of anxiety and stress? A systematic review and meta-analysis of randomized controlled trialsPhytother Res, 2022 · PMID 36017529
- 2The Effects of Rhodiola rosea L. Extract on Anxiety, Stress, Cognition and Other Mood SymptomsPhytother Res, 2015 · PMID 26502953
- 3A randomised, double-blind, placebo-controlled, parallel-group study of the standardised extract shr-5 of the roots of Rhodiola rosea in the treatment of subjects with stress-related fatiguePlanta Med, 2009 · PMID 19016404
- 4Ashwagandha: Is it helpful for stress, anxiety, or sleep? Fact Sheet for Health ProfessionalsNIH Office of Dietary Supplements, 2025
- 5Ashwagandha-induced liver injury: A case series from Iceland and the US Drug-Induced Liver Injury NetworkLiver Int, 2020 · PMID 31991029
- 6Effect of commercial Rhodiola rosea on CYP enzyme activity in humansEur J Clin Pharmacol, 2016 · PMID 26613955
- 7An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: A randomized, double-blind, placebo-controlled studyMedicine (Baltimore), 2019 · PMID 31517876
- 8Rhodiola (last updated April 2025)National Center for Complementary and Integrative Health, 2025
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