Ashwagandha vs Holy Basil
Ashwagandha (Withania somnifera) and holy basil or tulsi (Ocimum tenuiflorum) compared: how much research exists, what reviews say, and where safety information is thin.
Content last updated . This page has not been medically reviewed.
Safety first. Supplements can cause side effects and interact with medicines. Read mushroom safety and interactions before you use any mushroom product.
If stress, anxiety or low mood are getting in the way of daily life, talk to a clinician. In the US you can call or text 988 (Suicide & Crisis Lifeline). In an emergency, call 911. Ask a pharmacist before using either herb if you take medicines. [1]
The question
Both herbs are used in Ayurveda and both are called adaptogens in marketing. This page asks how they differ in what is documented. Short answer: ashwagandha has an NIH summary and a longer safety list; holy basil has a smaller, mostly low-quality human research base and much less safety detail in the sources we read.What each plant is
Ashwagandha is Withania somnifera, an evergreen shrub found in parts of India, Africa and the Middle East; supplements typically use the root, the leaf, or both. [1]Holy basil, also called tulsi, is Ocimum tenuiflorum, in the mint family (Lamiaceae). [2] A very common older name, Ocimum sanctum, is listed by GBIF as a synonym. [2] Tulsi is described as native to the Indian continent and highly revered for medicinal use within the Ayurvedic and Siddha medical systems. [3] That is traditional use. A review noted that one study used a named type (Krishna tulsi) while all other papers called the plant Ocimum sanctum without distinguishing cultivars, so results for one type or preparation may not apply to another. [3]
What research found
| Question | Ashwagandha | Holy basil |
|---|---|---|
| Overall summary | NCCIH (2023): some preparations may be effective for insomnia and stress; anxiety unclear [1] | A 2017 systematic review found 24 human studies on metabolic disorders, heart disease, immunity and neurocognition [3] |
| Quality | Many studies small, with varied preparations [1] | Only 3 of 24 were rated high quality, and only 8 used a placebo [3] |
| What the authors concluded | Limited evidence for a few uses; not enough for others [1] | Insufficient evidence for any specific tulsi formulation for any one condition; larger, longer, standardized studies needed [3] |
| Strength of evidence (our label) | Promising but limited (stress, sleep) | Insufficient evidence |
The 2017 review's own abstract says all studies reported favourable outcomes and none reported significant adverse events. [3] Because most of the studies were small and many lacked placebos, that should be read as early and uncertain rather than as proof.
Head-to-head evidence
Proper evidence not found. We did not read any trial comparing ashwagandha with holy basil. A 2026 trial in 186 people gave a formula of rhodiola, holy basil and schisandra, and separately a full-spectrum ashwagandha, each against placebo, and both reported lower perceived stress at day 60. [4] Holy basil was one of three herbs in that formula, so the result says nothing about holy basil alone or about which herb did better. We could not see funding in the abstract.No universal winner
Ashwagandha has a longer list of documented cautions; holy basil has a thinner list because less has been studied, not because it has been shown safe. Neither is a replacement for care of anxiety, depression, thyroid or blood sugar problems. More detail: holy basil for stress, blood sugar and thyroid and tulsi in Ayurveda.Frequently asked questions
Is holy basil the same as the basil I cook with?
Tulsi is Ocimum tenuiflorum; the sources we read do not address kitchen basil, so we cannot say how the two compare. [2]
Which is better for stress, ashwagandha or holy basil?
No direct comparison was found. Ashwagandha has agency-level statements; holy basil has a review of small studies. [1][3]
Is holy basil tea the same as a tulsi extract?
Not necessarily. Results for one preparation do not transfer to another, and the studies in the 2017 review used several forms. [3]
Can holy basil affect blood sugar or thyroid?
Several tulsi studies measured blood sugar. [3] We did not read a source on thyroid effects, so we make no claim.
Are they safe in pregnancy?
NCCIH advises avoiding ashwagandha in pregnancy. [1] For holy basil, safety in pregnancy is not described in the sources we read; ask a clinician.
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
| Point | Ashwagandha | Holy basil |
|---|---|---|
| Common effects | Drowsiness, stomach upset, diarrhea, vomiting [1] | None significant reported in the studies reviewed [3] |
| Liver | Rare cases of liver injury [1] | Not described in the sources we read |
| Medicines | May interact with diabetes and blood pressure medicines, sedatives, anti-seizure, thyroid and immune-suppressing medicines [1] | Not described in the sources we read |
| Pregnancy and breastfeeding | Avoid in pregnancy; not while breastfeeding [1] | Not described in the sources we read |
| Surgery, thyroid, autoimmune | Not recommended [1] | Not described in the sources we read |
"Not described in the sources we read" is not the same as safe. It means we did not find a regulator or agency page we could read on this point, and the human studies were small and short. Ask a pharmacist or clinician about holy basil, especially around diabetes medicines, because some tulsi studies measured blood sugar. [3] For general herb safety, see how interactions work and adaptogen medicine interactions.
References
- National Center for Complementary and Integrative Health (NIH). Ashwagandha: Usefulness and Safety. Page last updated March 2023. Read 2026-10-23.
- GBIF Secretariat. GBIF Backbone Taxonomy species match, queried for each plant name used on these pages. Read 2026-10-23.
- Jamshidi N, Cohen MM. The Clinical Efficacy and Safety of Tulsi in Humans: A Systematic Review of the Literature. Evid Based Complement Alternat Med. 2017 (full text on PMC5376420). Read 2026-10-23.
- Effects of multi-herb and ashwagandha root formulas on stress modulation: a randomized, double-blind, placebo-controlled clinical study. Trials. 2026 (PubMed abstract). Read 2026-10-23.