Tea & Extract Research
How much research tests the tea itself versus extracts and capsules, with an evidence snapshot across teas, tinctures and extracts, and how to read tea studies.
Content last updated . This page has not been medically reviewed.
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Evidence snapshot
Counts of PubMed records mentioning each tea, herb or preparation. Look at "chamomile tea", "peppermint tea" and "ginger tea" versus the plants themselves: few randomized trials test the tea, while many test extracts. A count shows how much has been published, not whether something works, and some searches (licorice, senna, green tea) include non-tea forms and non-health research.| Tea, herb or preparation | Records tagged as randomized controlled trials | Records tagged as any clinical trial | All PubMed records that mention it | Check it yourself |
|---|---|---|---|---|
| Chamomile tea | 4 | 5 | 83 | PubMed search |
| Peppermint tea | 2 | 3 | 31 | PubMed search |
| Ginger tea | 0 | 0 | 28 | PubMed search |
| Hibiscus (tea and products) | 36 | 41 | 918 | PubMed search |
| Rooibos | 4 | 7 | 440 | PubMed search |
| Lemon balm | 51 | 56 | 898 | PubMed search |
| Fennel | 34 | 36 | 1,466 | PubMed search |
| Lavender (includes oil and aromatherapy research) | 289 | 330 | 3,029 | PubMed search |
| Marshmallow root | 4 | 5 | 114 | PubMed search |
| Elderflower / Sambucus nigra | 7 | 14 | 1,066 | PubMed search |
| Dandelion | 6 | 12 | 1,831 | PubMed search |
| Nettle | 26 | 33 | 1,001 | PubMed search |
| Valerian | 59 | 73 | 772 | PubMed search |
| Passionflower | 19 | 21 | 287 | PubMed search |
| Licorice | 122 | 173 | 6,381 | PubMed search |
| Senna | 94 | 104 | 1,684 | PubMed search |
| Green tea (true tea) | 482 | 585 | 12,413 | PubMed search |
| Yerba mate | 24 | 27 | 715 | PubMed search |
| Herbal tea / tisane (general) | 43 | 51 | 1,596 | PubMed search |
| Detox tea | 0 | 0 | 5 | PubMed search |
| Tinctures | 52 | 81 | 1,657 | PubMed search |
| Herbal / standardized extracts | 179 | 210 | 2,264 | PubMed search |
Counted 2026-10-22 using NCBI E-utilities. Counts include studies of extracts, blends and non-health topics, and a trial can find no effect. A higher count means more human research has been indexed, not that something works.
What this means
- Chamomile tea: 4 randomized trials; peppermint tea: 2; ginger tea: none. NIH's evidence for chamomile, peppermint and ginger is mostly for supplements or oil capsules. [1][2][3]
- Hibiscus has a randomized trial of the tea (65 people, 6 weeks) and a 26-trial review of hibiscus products. [4][5]
- "Detox tea" returns almost no research: 5 records and no randomized trial. [6]
How to read tea studies
- Is it the tea? Compare the exact preparation with the one you drink.
- Dose, duration, population. The hibiscus trial used 3 servings (240 mL) a day for 6 weeks in adults with high-normal or mild high blood pressure. [4]
- Negative and mixed results count.
- Case reports show harm can happen but not how often. [7]
References
- National Center for Complementary and Integrative Health (NIH). Chamomile: Usefulness and Safety. Page last updated November 2024.
- National Center for Complementary and Integrative Health (NIH). Peppermint Oil: Usefulness and Safety. Page last updated May 2025. (Also describes peppermint leaf and tea.)
- National Center for Complementary and Integrative Health (NIH). Ginger: Usefulness and Safety. Page last updated February 2025.
- McKay DL, Chen CY, Saltzman E, Blumberg JB. Hibiscus sabdariffa L. tea (tisane) lowers blood pressure in prehypertensive and mildly hypertensive adults. J Nutr. 2010;140(2):298-303. PubMed 20018807. 65 adults, 6 weeks.
- Norouzzadeh M, et al. Efficacy and safety of Hibiscus sabdariffa in cardiometabolic health: An overview of reviews and updated dose-response meta-analysis. Complement Ther Med. 2025;89:103135. PubMed 39870328.
- National Center for Complementary and Integrative Health (NIH). "Detoxes" and "Cleanses": What You Need To Know.
- Gillett G, et al. Acute Severe Hyponatremia Following Use of "Detox Tea". Cureus. 2021;13(3):e14184. PubMed 33936895. A single case report (one 51-year-old woman).
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.