--- topic: "Adaptogens" title: "What Are Adaptogens?" order: 1 description: "A plain guide to what adaptogens are and how ashwagandha, rhodiola, ginseng, eleuthero, schisandra and holy basil compare on trial evidence and safety." question: "What are adaptogens, and which have real evidence?" answer: "Adaptogens may ease stress and fatigue modestly: ashwagandha has the most consistent trials, but quality is low, and the others have small or mixed evidence." actions: - "If you want to try one, start with ashwagandha: 12 trials pooled showed lower stress and anxiety scores, though the certainty of the evidence was low [1]." - "Set a clear goal and a fixed trial period, since benefits in sleep trials were clearer at eight weeks or longer, and stop if nothing changes [2]." - "Choose a standardized extract with an independent purity seal; our guide to [telling if a supplement is pure](/supplement-quality-and-testing/how-to-tell-if-a-supplement-is-pure) explains how." cautions: - "Stop ashwagandha and get medical care if you develop yellow skin or eyes, dark urine or itching; case reports describe liver injury within 2 to 12 weeks [3]." - "Pregnant, breastfeeding, or taking prescription medicines such as blood thinners, antidepressants or diabetes drugs? Ask a pharmacist first, and see [which herbs interact with medications](/herb-drug-interactions/which-herbs-interact-with-medications)." confidence: 2 confidenceNote: "Ashwagandha has a dozen small trials with low-certainty evidence; rhodiola, ginseng, eleuthero, schisandra and holy basil have few, small or conflicting trials, and the category itself is a traditional label." evidenceSummary: rctCount: 3 observationalCount: 0 metaAnalysisCount: 6 totalParticipants: "1,900+" replicated: false newestStudyYear: 2022 references: - id: "1" pmid: "36017529" title: "Does Ashwagandha supplementation have a beneficial effect on the management of anxiety and stress? A systematic review and meta-analysis of randomized controlled trials" authors: "Akhgarjand C, Asoudeh F, Bagheri A, et al." year: 2022 journal: "Phytother Res" - id: "2" pmid: "34559859" title: "Effect of Ashwagandha (Withania somnifera) extract on sleep: A systematic review and meta-analysis" authors: "Cheah KL, Norhayati MN, Husniati Yaacob L, et al." year: 2021 journal: "PLoS One" - id: "3" pmid: "31991029" title: "Ashwagandha-induced liver injury: A case series from Iceland and the US Drug-Induced Liver Injury Network" authors: "Björnsson HK, Björnsson ES, Avula B, et al." year: 2020 journal: "Liver Int" - id: "4" pmid: "27713248" title: "Effects of Adaptogens on the Central Nervous System and the Molecular Mechanisms Associated with Their Stress-Protective Activity" authors: "Panossian A, Wikman G" year: 2010 journal: "Pharmaceuticals (Basel)" - id: "5" pmid: "21036578" title: "The effectiveness and efficacy of Rhodiola rosea L.: a systematic review of randomized clinical trials" authors: "Hung SK, Perry R, Ernst E" year: 2011 journal: "Phytomedicine" - id: "6" pmid: "27822924" title: "Efficacy of Ginseng Supplements on Fatigue and Physical Performance: a Meta-analysis" authors: "Bach HV, Kim J, Myung SK, et al." year: 2016 journal: "J Korean Med Sci" - id: "7" pmid: "28400848" title: "The Clinical Efficacy and Safety of Tulsi in Humans: A Systematic Review of the Literature" authors: "Jamshidi N, Cohen MM" year: 2017 journal: "Evid Based Complement Alternat Med" - id: "8" pmid: "22643043" title: "Rhodiola rosea for physical and mental fatigue: a systematic review" authors: "Ishaque S, Shamseer L, Bukutu C, et al." year: 2012 journal: "BMC Complement Altern Med" - id: "9" pmid: "14971626" title: "Randomized controlled trial of Siberian ginseng for chronic fatigue" authors: "Hartz AJ, Bentler S, Noyes R, et al." year: 2004 journal: "Psychol Med" - id: "10" pmid: "19500070" title: "Evidence-based efficacy of adaptogens in fatigue, and molecular mechanisms related to their stress-protective activity" authors: "Panossian A, Wikman G" year: 2009 journal: "Curr Clin Pharmacol" - id: "11" pmid: "33710261" title: "Effect of Schisandra chinensis Baillon extracts and regular low-intensity exercise on muscle strength and mass in older adults: a randomized, double-blind, placebo-controlled trial" authors: "Cho YH, Lee SY, Lee CH, et al." year: 2021 journal: "Am J Clin Nutr" - id: "12" pmid: "36185698" title: "A randomized, double-blind, placebo-controlled trial investigating the effects of an Ocimum tenuiflorum (Holy Basil) extract (Holixer(TM)) on stress, mood, and sleep in adults experiencing stress" authors: "Lopresti AL, Smith SJ, Metse AP, et al." year: 2022 journal: "Front Nutr" --- Adaptogens are herbs, such as ashwagandha, rhodiola, ginseng, eleuthero, schisandra and holy basil, said to raise the body's "nonspecific resistance" to stress [4]. Ashwagandha has the most consistent trial results for stress, anxiety and sleep, but the evidence is low quality [1][2]. Rhodiola, ginseng and holy basil show smaller or mixed results [5][6][7]. "Adaptogen" is a traditional label, not proof that a herb works. ## How it works The word was first defined for substances that enhance the "state of nonspecific resistance" during stress. Proposed mechanisms involve the stress-hormone axis, cortisol, nitric oxide and stress-protein pathways, but most of that evidence comes from animals and isolated cells [4]. For readers, the useful question is what each herb has shown in people. **A herb-by-herb grade** - **Ashwagandha (best supported).** Twelve randomized trials (1,002 adults) pooled to lower anxiety and stress scores, but results varied widely and the certainty was low [1]. Five trials (400 adults) found better sleep [2]. Case reports describe liver injury [3]. See our [ashwagandha evidence page](/ashwagandha/evidence-and-dosing). - **Rhodiola (mixed).** Two systematic reviews of 11 trials disagree: one finds contradictory results with every trial at risk of bias [8], the other finds possible benefit but no independent replication [5]. See [rhodiola](/rhodiola/stress-and-fatigue). - **Panax ginseng (modest).** Pooled trials showed a small drop in fatigue but no gain in physical performance, and the authors called the evidence insufficient [6]. See [ginseng](/ginseng/energy-cognition-and-immunity). - **Eleuthero (weak).** A 96-person trial in chronic fatigue found no overall benefit [9]. See [eleuthero](/eleuthero/adaptogen-for-stress-and-endurance). - **Schisandra (preliminary).** A review of older studies reported better endurance and mental performance in mild fatigue [10]; a modern 54-person trial tested muscle strength instead [11]. See [schisandra](/schisandra/adaptogen-liver-and-cognition). - **Holy basil (promising, small).** A review of 24 studies reported favorable outcomes in all of them [7], and one 100-person, 8-week trial lowered perceived stress [12]. See [holy basil](/holy-basil/adaptogen-and-stress). **What to do with this.** Pick one herb, one standardized product, and one measurable goal. Basics such as sleep, movement and daylight come first, and none of these herbs replaces care for depression, anxiety disorders or exhaustion that does not lift. ## The evidence in detail ### Ashwagandha Akhgarjand and colleagues pooled 12 randomized trials (1,002 adults aged 25 to 48). Ashwagandha lowered anxiety (standardized mean difference -1.55, 95% CI -2.37 to -0.74) and stress (-1.75, -2.29 to -1.22) against placebo, but heterogeneity was very high (I-squared 94% and 83%) and the authors graded the certainty of evidence low. Dose-response analysis suggested stress benefit at 300 to 600 mg a day [1]. Effects this large, with this much inconsistency, usually point to small-study bias and should be read cautiously. A separate meta-analysis of five trials (400 adults) found a significant sleep improvement (SMD -0.59, 95% CI -0.75 to -0.42), clearer in people with insomnia, at 600 mg a day or more, and after eight weeks or longer. Safety data were limited [2]. Björnsson and colleagues described five patients (mean age 43) with jaundice 2 to 12 weeks after starting ashwagandha products. Injury was cholestatic or mixed, and liver tests normalized within one to five months in four; one was lost to follow-up, and one case also involved rhodiola [3]. ### Rhodiola Ishaque and colleagues found 11 trials of rhodiola for fatigue (10 randomized). Two of six physical-fatigue trials and three of five mental-fatigue trials were positive, and all had a high or unclear risk of bias, so they called the evidence contradictory [8]. Hung and colleagues reviewed 11 placebo-controlled trials and judged the quality of most to be moderate or good, with only mild adverse events, but noted the lack of independent replication [5]. Both conclusions can be true: promising but unreplicated. ### Eleuthero and ginseng Hartz and colleagues randomized 96 adults with unexplained fatigue for six months or longer to Siberian ginseng or placebo; 76 gave two-month data. Fatigue fell in both arms, and the difference was not significant overall. A subgroup with less severe fatigue (n=45) improved at P=0.04, unadjusted for multiple comparisons, so this is a hint only [9]. A meta-analysis of 12 trials with 630 participants found ginseng reduced fatigue (SMD 0.34, 95% CI 0.16 to 0.52, four trials) but did not improve physical performance (SMD -0.01, 95% CI -0.29 to 0.27, eight trials). The authors judged the evidence insufficient because trials were few and small [6]. ### Schisandra The strongest claims come from a narrative review by long-time adaptogen researchers, which rated the evidence "good" for schisandra and eleuthero in mild fatigue and "strong" for one rhodiola extract [10]. A narrative review is not a pooled analysis, and the eleuthero verdict sits beside Hartz's null trial. A 12-week trial of 54 adults over 50 found 1 g a day of schisandra extract raised knee-extension strength by 10.2 Nm on the right (95% CI 3.7 to 16.8) and 6.7 Nm on the left (0.3 to 13.1) compared with placebo, but not muscle mass [11]. That is not a stress outcome. ### Holy basil Jamshidi and Cohen reviewed 24 human studies and reported favorable outcomes in all and no significant adverse events [7]. A body of research in which every study is positive deserves caution about publication bias. In a randomized, double-blind trial, 100 stressed adults took 125 mg twice daily for eight weeks: perceived stress (P=0.003), insomnia scores (P=0.025) and hair cortisol (P=0.025) improved against placebo, and salivary cortisol was lower after a lab stress test [12]. It is one short, single-product trial. ### Where the evidence disagrees Ashwagandha trials agree in direction but not in size. Rhodiola reviews disagree on quality. Ginseng helps fatigue scores but not performance. Mechanistic claims rest mostly on animal and cell work [4]. **Bottom line (confidence 2 of 5).** Adaptogens are a convenient grouping of traditional stress herbs, not a proven pharmacological class. Ashwagandha has the most consistent human evidence, with low certainty and a liver-injury signal from case reports. For the others, expect small, uncertain effects.