Adaptogens and Stress Resilience: What Research Says About Longevity

Key Takeaways

  • Adaptogens are a category of herbs traditionally used to help the body adapt to stress. The term is not a regulatory classification and carries no approved health claims from EFSA.
  • A meta-analysis of 12 RCTs (1,002 participants) found that ashwagandha supplementation was associated with significant reductions in self-reported stress and anxiety, though the certainty of the evidence was rated as low.1
  • A 2024 meta-analysis of 9 RCTs (558 participants) found that ashwagandha was associated with significant reductions in perceived stress scores and serum cortisol levels compared to placebo.2
  • A meta-analysis of 5 RCTs (400 participants) found that ashwagandha had a small but significant effect on overall sleep quality, with stronger effects at doses of 600 mg/day or above and durations of 8 weeks or more.3
  • Evidence for rhodiola rosea and ginseng is more limited, with systematic reviews noting inconsistent outcomes and methodological concerns across available trials.4,5
  • No adaptogens have EFSA-approved health claims. All findings should be framed as "studied for" rather than "effective for."
  • Magnesium and vitamin B6 contribute to the reduction of tiredness and fatigue, and to normal psychological function (EFSA-approved claims), and are well-established nutrients that may complement lifestyle-based stress management strategies.

What Are Adaptogens?

The concept of adaptogens was first formalised in the 1940s and 1950s by the Soviet scientist Nikolai Lazarev, and later refined by Israel Brekhman. Their proposed criteria for an adaptogen were: it should be relatively non-toxic, it should produce a non-specific resistance to stress, and it should have a normalising influence on physiology regardless of the direction of change caused by the stressor.

The herbs most commonly classified as adaptogens include ashwagandha (Withania somnifera), rhodiola rosea, Panax ginseng, holy basil (Ocimum sanctum), and schisandra (Schisandra chinensis). These plants have long histories of traditional use across Ayurvedic, Chinese, and Scandinavian folk medicine systems.

It is important to note that "adaptogen" is not a regulatory classification. It is a concept from traditional medicine and early pharmacological research, not a designation recognised by EFSA, the FDA, or other regulatory bodies. None of the adaptogens discussed in this article carry EFSA-approved health claims. All evidence presented should be understood as "has been studied for" rather than "is proven to."

The proposed mechanism of adaptogenic action centres on the hypothalamic-pituitary-adrenal (HPA) axis, which regulates the body's cortisol response to stress. In theory, adaptogens may help modulate the magnitude or duration of the cortisol response, supporting a more balanced physiological reaction to stressors. However, the precise mechanisms remain incompletely understood in humans.

Ashwagandha: The Most Studied Adaptogen

Ashwagandha (Withania somnifera) is the adaptogen with the largest body of human clinical trial data. Its active compounds, known as withanolides, are believed to be responsible for its biological effects. Standardised extracts (typically containing 2.5-5% withanolides) are the most commonly studied form.

Stress and cortisol outcomes

A 2022 systematic review and dose-response meta-analysis of 12 RCTs involving 1,002 participants (aged 25-48 years) found that ashwagandha supplementation was associated with significant reductions in both anxiety (SMD: -1.55, 95% CI: -2.37 to -0.74) and self-reported stress (SMD: -1.75, 95% CI: -2.29 to -1.22) compared to placebo. The dose-response analysis suggested that effects on stress were most favourable at doses of 300-600 mg/day. However, the certainty of the evidence was rated as low for both outcomes, and heterogeneity between studies was high.1

A 2024 meta-analysis of 9 RCTs involving 558 participants confirmed these findings, reporting significant reductions in perceived stress scale scores (MD = -4.72, 95% CI: -8.45 to -0.99), Hamilton Anxiety Scale scores (MD = -2.19, 95% CI: -3.83 to -0.55), and serum cortisol levels (MD = -2.58, 95% CI: -4.99 to -0.16) compared to placebo. Study durations ranged from 30 to 90 days, with doses between 125-600 mg daily.2

Important limitations

While the direction of effect across meta-analyses is consistent, several limitations are important to acknowledge. Most individual trials have small sample sizes (typically 40-80 participants). Study durations are generally short (4-12 weeks). Many trials have been funded by supplement manufacturers. Heterogeneity between studies is high, meaning the true effect size remains uncertain. Standardisation of extracts varies between trials, making direct comparisons difficult. Larger, independently funded, longer-duration trials are needed to confirm these findings.

Sleep outcomes

A 2021 systematic review and meta-analysis examined 5 RCTs (400 participants) of ashwagandha extract for sleep outcomes. The analysis found a small but significant effect on overall sleep quality (SMD: -0.59, 95% CI: -0.75 to -0.42). The effects were more pronounced in individuals diagnosed with insomnia, at doses of 600 mg/day or above, and with treatment durations of 8 weeks or longer. Ashwagandha also improved mental alertness upon waking and was associated with reduced anxiety. No serious adverse effects were reported.3

A separate 2024 systematic review of RCTs evaluating ashwagandha for both anxiety and sleep confirmed improvements in sleep parameters including sleep onset latency, total sleep time, and Pittsburgh Sleep Quality Index (PSQI) scores, though it noted that further research with larger sample sizes is needed.6

Rhodiola, Ginseng, and Other Adaptogens

Rhodiola rosea

Rhodiola rosea (also known as golden root or Arctic root) has been traditionally used in Scandinavian and Russian folk medicine for centuries. Its key bioactive compounds include rosavin and salidroside. A 2012 systematic review identified 11 clinical trials (10 RCTs, 1 CCT) examining rhodiola for physical and mental fatigue. Two of six trials on physical fatigue reported benefits, and some evidence suggested improvements in mental performance under stress-induced conditions. However, the review concluded that methodological flaws across studies limited accurate assessment of efficacy, and no two studies reported the same outcomes, preventing meta-analysis.4

A separate systematic review of 11 RCTs concluded that rhodiola may have beneficial effects on physical performance, mental performance, and certain stress-related outcomes, but noted a lack of independent replications of individual findings.7 It is worth noting that rhodiola is generally considered more energising than sedating, which distinguishes it from ashwagandha in terms of practical use. For this reason, rhodiola is typically not recommended as a sleep support.

Panax ginseng

Panax ginseng (Korean ginseng) contains ginsenosides as its primary active compounds. A 2024 systematic review and meta-analysis of 15 RCTs (671 participants) examining the effects of ginseng on cognitive function found a significant effect on memory improvement (SMD = 0.19, 95% CI: 0.02 to 0.36), though the effect size was small. The authors noted that the quality of evidence was mixed and called for more rigorous trials.5

Regarding fatigue, a 2023 systematic review and meta-analysis of RCTs found that ginseng herbal formulas produced significant reductions in general (non-disease-specific) fatigue compared to controls (SMD: -0.48, 95% CI: -0.71 to -0.25), though effect sizes were small. The review concluded that rigorous RCTs and standardised guidelines for ginseng usage are needed.8

Holy basil and schisandra

Holy basil (Ocimum sanctum, also known as tulsi) and schisandra have traditional use in Ayurvedic and Chinese medicine respectively. However, the number of well-designed human RCTs for these herbs is very limited. Early-stage human studies exist for both, but systematic reviews with robust conclusions are lacking. These adaptogens should be considered at an earlier stage of clinical investigation than ashwagandha or rhodiola.

Adaptogens and Sleep: What Evidence Supports?

For individuals seeking natural support for sleep quality, it is important to distinguish between adaptogens that have been studied for sleep and those that are more stimulating in nature.

Ashwagandha is the only adaptogen with meta-analytic support for sleep outcomes. As noted above, the evidence suggests a modest benefit, particularly at higher doses and in individuals with existing sleep difficulties.3 The proposed mechanism involves modulation of the HPA axis (cortisol reduction) and possible GABAergic activity, though these pathways require further investigation in humans.

Rhodiola, by contrast, is typically studied for its energising and mental performance effects and is generally not associated with sedation or sleep promotion. Taking rhodiola close to bedtime could theoretically be counterproductive for sleep quality.

Lifestyle factors remain the foundation of healthy sleep. Consistent sleep schedules, appropriate light exposure, physical activity, and stress management techniques such as deep breathing exercises are well-established strategies that should not be overlooked in favour of supplementation.

Magnesium and vitamin B6, which contribute to the reduction of tiredness and fatigue and to normal psychological function (EFSA-approved claims), represent well-characterised nutritional options with a clearer regulatory standing than herbal adaptogens.

Quality, Safety, and Selection

The quality and safety of adaptogen supplements is a significant concern for consumers. Several factors deserve attention.

Standardisation matters. The biological activity of herbal extracts depends on the concentration of active compounds. For ashwagandha, this means withanolide content; for rhodiola, rosavin and salidroside content. Products that do not disclose or standardise active compound levels may deliver inconsistent results.

Contamination risks in herbal products are well-documented. Heavy metal contamination, pesticide residues, and microbial contamination have been reported in herbal supplement testing. Third-party testing, Certificates of Analysis (COAs), and independent laboratory verification are important markers of quality control.

Potential interactions with medications should be considered. Ashwagandha may interact with thyroid medications, sedatives, and immunosuppressants. Ginseng may interact with blood-thinning medications and certain antidiabetic drugs. Anyone taking prescription medication should consult a healthcare professional before starting adaptogen supplementation.

Safety monitoring is ongoing. Regulatory bodies in some countries have issued cautionary statements regarding ashwagandha and liver health. While reports of liver injury appear rare, they highlight the importance of responsible dosing, product quality, and medical oversight. Denmark and some other countries have introduced restrictions on ashwagandha-containing supplements as a precautionary measure.

Questions and Answers

What are adaptogens?

Adaptogens are a category of plant-derived compounds traditionally believed to help the body adapt to physical and psychological stress. The concept was formalised by Soviet researchers in the mid-20th century. Common adaptogens include ashwagandha, rhodiola rosea, and Panax ginseng. The term is not a regulatory classification and carries no EFSA-approved health claims.

Does ashwagandha reduce stress?

Meta-analyses of RCTs have found that ashwagandha supplementation is associated with reductions in self-reported stress, anxiety scores, and serum cortisol levels compared to placebo.1,2 However, the certainty of the evidence is rated as low, most trials are small and short-term, and larger independent studies are needed to confirm these effects.

Can ashwagandha help with sleep?

A meta-analysis of 5 RCTs found a small but significant improvement in sleep quality with ashwagandha supplementation, with stronger effects in those with insomnia, at doses of 600 mg/day or above, and with treatment durations of 8 weeks or longer.3 The evidence is promising but still limited in volume.

Is rhodiola rosea effective for fatigue?

Systematic reviews have found some evidence suggesting that rhodiola may help with physical and mental fatigue, but the evidence is contradictory across studies. Methodological limitations and a lack of independent replications prevent firm conclusions.4,7 More rigorous research is needed.

Does ginseng improve cognitive function?

A 2024 meta-analysis of 15 RCTs found a small but statistically significant effect of ginseng on memory improvement, though the overall evidence quality was mixed.5 Ginseng has also been studied for fatigue management, with modest positive findings for general fatigue in a separate meta-analysis.8

Are adaptogens safe?

In the clinical trials reviewed, adaptogens have generally been well tolerated with few reported serious adverse events. However, long-term safety data are limited. Ashwagandha may interact with thyroid medications, sedatives, and immunosuppressants. Some regulatory bodies have issued precautionary statements regarding ashwagandha and liver health. Always consult a healthcare professional before starting supplementation, particularly if taking medication.

Which adaptogen is best for sleep versus stress?

Ashwagandha has the most human evidence for both stress and sleep outcomes. Rhodiola is generally considered more energising and is typically studied for fatigue and mental performance rather than sleep. Taking rhodiola close to bedtime may be counterproductive. For sleep specifically, ashwagandha has the strongest (though still limited) meta-analytic support.3

Do adaptogens have EFSA-approved health claims?

No. None of the adaptogens discussed in this article carry EFSA-approved health claims. All findings should be interpreted as "studied for" or "associated with" rather than "proven to" or "effective for." Nutrients such as magnesium and vitamin B6, which contribute to the reduction of tiredness and fatigue and to normal psychological function, have a clearer regulatory standing (EFSA-approved claims).

Frequently Asked Questions

What is the best adaptogen for stress?

Ashwagandha has the largest body of human RCT evidence for stress-related outcomes, with multiple meta-analyses reporting significant reductions in perceived stress and cortisol levels.1,2 However, the evidence is still considered low certainty, and individual responses may vary. No adaptogen carries an EFSA-approved health claim for stress.

Can I take adaptogens with other supplements?

Many people combine adaptogens with other nutritional supplements. However, potential interactions should be considered. Ashwagandha may interact with thyroid, sedative, and immunosuppressant medications. Ginseng may interact with blood-thinning and antidiabetic drugs. Consult a healthcare professional if you take prescription medication or multiple supplements.

How long does it take for ashwagandha to work?

In clinical trials, effects on stress and cortisol have typically been observed from 4 weeks onward, with sleep benefits more commonly reported at 8 weeks or longer.3,2 Most studies use durations of 30 to 90 days. Individual responses may vary based on baseline stress levels, dose, and extract standardisation.

Are adaptogens better than lifestyle changes for stress?

No. Lifestyle strategies including regular physical activity, adequate sleep, stress management techniques, social connection, and balanced nutrition are the foundation of stress resilience. Adaptogens may be considered as a complement to, not a replacement for, these evidence-based approaches. Nutrients such as magnesium and vitamin B6, which contribute to the reduction of tiredness and fatigue (EFSA-approved claims), offer well-established nutritional support.

What dose of ashwagandha is studied for stress and sleep?

Most human RCTs have used standardised root extracts at doses ranging from 125 to 600 mg per day. The dose-response analysis from a 2022 meta-analysis suggested that 300-600 mg/day was the most favourable range for stress outcomes.1 For sleep, effects were stronger at 600 mg/day or above.3

Should I choose rhodiola or ashwagandha?

The choice depends on the intended use. Ashwagandha has stronger human evidence for stress reduction and sleep improvement. Rhodiola is more commonly studied for mental performance and physical fatigue, and is considered more stimulating.4 Neither carries EFSA-approved health claims, and both require more research before firm recommendations can be made.

References

  1. Akhgarjand C, Asoudeh F, Bagheri A, et al. Does Ashwagandha supplementation have a beneficial effect on the management of anxiety and stress? A systematic review and meta-analysis of randomized controlled trials. Phytother Res. 2022;36(11):4115-4124. View on PubMed ↗
  2. Arumugam V, Vijayakumar V, Balakrishnan A, et al. Effects of Ashwagandha (Withania Somnifera) on stress and anxiety: A systematic review and meta-analysis. Explore (NY). 2024;20(6):103062. View on PubMed ↗
  3. Cheah KL, Norhayati MN, Husniati Yaacob L, Abdul Rahman R. Effect of Ashwagandha (Withania somnifera) extract on sleep: A systematic review and meta-analysis. PLoS One. 2021;16(9):e0257843. View on PubMed ↗
  4. Ishaque S, Shamseer L, Bukutu C, Vohra S. Rhodiola rosea for physical and mental fatigue: a systematic review. BMC Complement Altern Med. 2012;12:70. View on PubMed ↗
  5. Zeng M, Zhang K, Yang J, et al. Effects of Ginseng on Cognitive Function: A Systematic Review and Meta-Analysis. Phytother Res. 2024. View on PubMed ↗
  6. Fatima K, Malik J, Muskan F, et al. Safety and efficacy of Withania somnifera for anxiety and insomnia: Systematic review and meta-analysis. Hum Psychopharmacol. 2024;39(5):e2911. View on PubMed ↗
  7. Hung SK, Perry R, Ernst E. The effectiveness and efficacy of Rhodiola rosea L.: a systematic review of randomized clinical trials. Phytomedicine. 2011;18(4):235-244. View on PubMed ↗
  8. Li X, Yang M, Zhang YL, et al. Ginseng and Ginseng Herbal Formulas for Symptomatic Management of Fatigue: A Systematic Review and Meta-Analysis. J Integr Complement Med. 2023;29(8):468-482. View on PubMed ↗

Disclaimer: Educational content only. Not medical advice. Supplements are not intended to diagnose, treat, cure, or prevent any disease. Consult a qualified healthcare professional if you have a medical condition or take medication.