Traditional Use vs. Clinical Evidence
How long-standing traditional use of adaptogen herbs differs from clinical trial evidence, what European and US bodies say about each, and why neither one settles the question alone.
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Short answer. Traditional use and clinical evidence are two different kinds of knowledge. Traditional use tells you how people have used a plant over a long time. Clinical trials test a specific preparation in a specific group of people. Neither one proves the other, and a plant can have a long tradition and weak trial evidence, or the reverse. If you take any medicine, ask a pharmacist or clinician before adding an herb; see how medicine interactions work.
How the sources define the terms
"Adaptogen" is a contested word. The European Medicines Agency's herbal committee (HMPC, 2008) traces it to N. V. Lazarev (1947), who used it for a substance claimed to raise "non-specific" resistance to stress. [1] The same paper says the term is not accepted in the pharmacological and clinical vocabulary commonly used in the EU, and is not appropriate for a marketing authorisation. [1] A 2018 review says adaptogen has generally been used as a functional term. [2] For more on the word itself, see What are adaptogens?.In EU rules, "traditional use" has a narrow meaning. A traditional use registration does not require new clinical trials on safety and efficacy, as long as sufficient safety data and plausible efficacy are shown. [3] The EU monograph for rhodiola (Rhodiola rosea L., rhizome and root; revised March 2024) describes a product "exclusively based upon long-standing use". [4] That wording describes how a product is registered. It does not say the herb was proven in trials.
Traditional use (not proof)
These are descriptions of tradition, not findings.- Ashwagandha (Withania somnifera, root): NCCIH says it has been used as a medicinal plant for thousands of years, especially in traditional Ayurvedic medicine. [5] See ashwagandha in Ayurveda.
- Asian ginseng (Panax ginseng, root): NCCIH says it has been used as a calming agent in traditional Chinese medicine and as an adaptogen. [6] See ginseng in Chinese medicine.
- Rhodiola (Rhodiola rosea, rhizome and root): a 2021 review says it is used in the ethnomedicines of Arctic peoples and in national systems of traditional medicine. [7] NCCIH lists traditional uses including work performance, endurance, fatigue, depression and altitude sickness. [8]
Clinical evidence (what trials found)
| Question | What the source found | Our evidence label |
|---|---|---|
| Ashwagandha for stress and anxiety | A 2022 meta-analysis of 12 trials (1,002 adults, extract) found lower anxiety and stress scores than placebo, but rated the certainty of the evidence low for both. [9] | Promising but limited |
| Ashwagandha, overall | NCCIH says some preparations may be effective for insomnia and stress, that many studies were small, and that they used a variety of preparations. [5] | Promising but limited |
| Rhodiola for fatigue | A 2012 systematic review of 11 trials called the research contradictory; every included study had a high or unclear risk of bias. [10] NCCIH says there is not enough reliable evidence to say whether rhodiola is useful for any health-related purpose. [8] | Mixed, insufficient evidence |
| Asian ginseng for fatigue | NCCIH describes a 2023 review of 19 studies suggesting Asian ginseng alone may have a small benefit on general fatigue, and notes that not all research agrees. [6] | Mixed |
| Eleutherococcus (eleuthero) root | The EMA committee found no study sufficient to show efficacy in a clearly defined clinical condition. [1] | Insufficient evidence |
Each row applies to the plant part, extract and population in that source. A result for one ashwagandha extract does not carry over to a different extract, or to a different plant such as American ginseng.
Why one does not settle the other
- Tradition is not proof. A long history shows people used a plant. It does not show how well it works, for whom, or how safely. NCCIH notes liver injury has been linked to ashwagandha supplements, though it is rare. [5]
- A weak trial does not erase tradition. Small or short trials may simply be unable to answer the question. The EMA committee judged the data enough to justify further research into the adaptogen concept. [1]
- Traditional forms differ from supplements. Teas, decoctions and whole roots used in a tradition are not the same as a modern capsule extract. Trials say little about traditional preparations unless they tested them.
Frequently asked questions
Does a long history of use mean an adaptogen works?
No. A long history shows that people have used the plant, which is useful information about tradition. Whether it works needs trials of a defined preparation. The EMA committee describes registration as "traditional" when it rests on long-standing use rather than new trials. [4]
Are clinical trials the only evidence that counts?
No. Trials answer a different question from tradition. Both are described here under separate labels, and neither is used to dismiss the other.
Why do trials disagree about the same herb?
Preparations, amounts, people and outcome scales differ. NCCIH notes that ashwagandha studies used a variety of preparations, and the 2022 meta-analysis reported very high heterogeneity between its trials (I² 93.8% for anxiety). [5][9]
Is a traditional herbal medicine product in Europe proven to work?
Not through trials. Traditional use registration does not require clinical trials on efficacy if plausible efficacy and sufficient safety data are shown. [3]
Where can I read about the traditions themselves?
Therapies covers traditions in their own terms, for example Ayurveda and Traditional Chinese Medicine.
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety and who should ask first
References
- European Medicines Agency, Committee on Herbal Medicinal Products (HMPC). Reflection paper on the adaptogenic concept. EMEA/HMPC/102655/2007, adopted 8 May 2008. Read 2026-10-23.
- Liao LY, He YF, Li L, et al. A preliminary review of studies on adaptogens: comparison of their bioactivity in TCM with that of ginseng-like herbs used worldwide. Chin Med. 2018. PubMed 30479654, full text at PMC6240259. Read 2026-10-23.
- European Medicines Agency. Herbal medicinal products. Regulatory overview page. Read 2026-10-23.
- European Medicines Agency, HMPC. European Union herbal monograph on Rhodiola rosea L., rhizoma et radix. EMA/HMPC/24177/2023, Final, Revision 1, 20 March 2024. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NIH). Ashwagandha: Usefulness and Safety. Last updated March 2023. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NIH). Asian Ginseng: Usefulness and Safety. Page read 2026-10-23. Read 2026-10-23.
- Brinckmann JA, Cunningham AB, Harter DEV. Running out of time to smell the roseroots: reviewing threats and trade in wild Rhodiola rosea L. J Ethnopharmacol. 2021. PubMed 33358852. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NIH). Rhodiola: Usefulness and Safety. Page read 2026-10-23. Read 2026-10-23.
- 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. PubMed 36017529. Read 2026-10-23.
- Ishaque S, Shamseer L, Bukutu C, Vohra S. Rhodiola rosea for physical and mental fatigue: a systematic review. BMC Complement Altern Med. 2012. PubMed 22643043. Read 2026-10-23.