Ashwagandha has 77 clinical trials tagged in PubMed and holy basil has 21, and most of holy basil's are not about stress. That gap is the honest starting point for choosing between the 2.
Both are called adaptogens. They are not interchangeable, and 1 of them has a much deeper evidence base.
Quick Answer: Holy Basil or Ashwagandha?
For stress, ashwagandha has more evidence: 77 tagged clinical trials in PubMed against 21 for holy basil, and a 2022 review found its morning cortisol-lowering effect the most consistent of any plant. Holy basil has 2 positive stress trials, both of extracts. Neither suits pregnancy, and taking them together is untested.
Key Takeaways
- PubMed tags 77 clinical trials on ashwagandha and 21 on holy basil.
- A 2022 review of 52 trials found ashwagandha's cortisol effect most consistent.
- Holy basil has 2 positive placebo-controlled stress trials, both using extracts.
- A 2026 trial compared a 3-herb blend with ashwagandha, not tulsi alone.
- No trial has tested the 2 herbs together without other ingredients.
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Two Different Plants
Holy basil and ashwagandha share a tradition and a marketing label, and very little else. One is an aromatic leaf from the mint family, the other a root from the nightshade family, and they are taken, tasted and studied differently.
| Holy basil | Ashwagandha | |
|---|---|---|
| Plant | Ocimum tenuiflorum | Withania somnifera |
| Part used | Leaf, sometimes stem | Root |
| Family | Lamiaceae, the mint family | Solanaceae, the nightshade family |
| Common forms | Tea, capsule, tincture | Capsule, powder, tincture |
| Our capsule | 1,000 mg | 1,000 mg |
Tulsi holds a preeminent place among Ayurvedic herbs, which is where the adaptogen framing comes from.[1]Tulsi - Ocimum sanctum: A herb for all reasons — Journal of Ayurveda and Integrative Medicine (2014) View source For the leaf on its own terms, see the holy basil explainer.
The Evidence, Counted
Counting PubMed records is a blunt tool, and it still tells you something useful here. Ashwagandha has roughly twice the records and more than 3 times the tagged trials, and many of holy basil's tagged trials are mouthwash and dental studies.
| PubMed, 2026-09-18 | Holy basil | Ashwagandha |
|---|---|---|
| Records | 1,069 | 2,050 |
| Tagged clinical trials | 21 | 77 |
| Of those, the herb alone swallowed by people | 4 | Not classified here |
| Tagged trials mentioning sleep or insomnia | 1, a 3-herb formula | 15 |
| Records mentioning both | 64 | 64 |
The 2017 review of tulsi found 24 human studies, all favourable, but small and varied.[2]The Clinical Efficacy and Safety of Tulsi in Humans: A Systematic Review of the Literature — Evidence-Based Complementary and Alternative Medicine (2017) View source Neither count includes much tea research, which matters if you plan to take tulsi as a tea instead.
The Cortisol Result
Cortisol is the comparison people search for, and there is a direct answer. A 2022 systematic review of 52 randomized trials of single plants on stress hormones found most effects unclear, with 1 exception.
- Ashwagandha: the most consistent morning cortisol-lowering result.
- Holy basil: included, with the effect unclear.
- Holy basil since then: 1 trial found lower hair cortisol at 8 weeks.
- Bottom line: ashwagandha leads on this measure.
The review searched to October 2020 and named ashwagandha as its most consistent finding.[3]Modulation of the hypothalamic-pituitary-adrenal (HPA) axis by plants and phytonutrients: a systematic review of human trials — Nutritional Neuroscience (2022) View source
The 2022 holy basil trial, published after that search, used 125 mg of extract twice daily.[4]A randomized, double-blind, placebo-controlled trial investigating the effects of an Ocimum tenuiflorum (Holy Basil) extract on stress, mood, and sleep in adults experiencing stress — Frontiers in Nutrition (2022) View source
The Only Trial That Put Them Side by Side
Competitor pages cite a 2026 trial as a holy basil versus ashwagandha comparison. It is not quite that, and the difference matters if you are trying to choose between the 2 herbs on evidence.
- People: 186 adults with high stress, 60 days.
- Arm 1: a formula of rhodiola, holy basil and schisandra.
- Arm 2: a full-spectrum ashwagandha.
- Result: both lowered perceived stress versus placebo.
Because holy basil was 1 of 3 herbs in its arm, the trial cannot tell you how tulsi alone compares with ashwagandha.[5]Effects of multi-herb and ashwagandha root formulas on stress modulation: a randomized, double-blind, placebo-controlled clinical study — Trials (2026) View source
Taking Them Together
Holy basil and ashwagandha often sit in the same calming formula, so many people are already taking both. No trial has tested the pair on its own, which means combining them is reasonable to discuss but impossible to judge from evidence.
- Tested as a pair: never, without other herbs in the mix.
- Tested in blends: yes, including a 5-herb tea.
- Practical advice: start 1, add the other after 4 weeks.
- Check blends: you may already be taking both.
If you do combine them, work out capsule, tincture and timing for holy basil before adding anything else.
Safety Differences
Both herbs were well tolerated in short trials, and both should be avoided in pregnancy. Beyond that their caution lists differ, and the differences are a better way to choose than any claim about which is stronger.
- Holy basil: blood sugar with diabetes drugs, animal fertility data.
- Holy basil: 1 mouse study on thyroxine.
- Ashwagandha: its own separate list, covered in our ashwagandha guides.
- Both: avoid in pregnancy and when trying to conceive.
If you take diabetes medicine, that caution applies to holy basil in particular, because of the 1996 glucose trial.[6]Randomized placebo-controlled, single blind trial of holy basil leaves in patients with noninsulin-dependent diabetes mellitus — International Journal of Clinical Pharmacology and Therapeutics (1996) View source
Where Each Fits
Choosing is simpler than the marketing makes it. Pick on evidence, form and safety, then give the choice 8 weeks before judging it, the longest period the holy basil trials ran.
- Want the deeper evidence base: ashwagandha.
- Want a leaf you can also brew: holy basil.
- On diabetes medicine: ask before either, especially holy basil.
- Pregnant or planning: neither.
If the leaf suits you, remedy's holy basil capsules hold 1,000 mg of whole leaf and stem.
Speak to a Clinician Before Taking Either Herb If
- You are pregnant, breastfeeding or trying to conceive, where the only data comes from animals
- You take insulin, a sulfonylurea, metformin or any other glucose-lowering medicine
- You have a thyroid condition or take thyroid medication
- You have surgery planned within the next 2 weeks
- You already take a blend that contains holy basil, so you would be doubling it
Frequently Asked Questions
What is better, ashwagandha or holy basil? +
For stress, ashwagandha has more evidence: 77 tagged trials against 21. Holy basil may suit people who want a leaf they can also brew as tea.
Can you take holy basil and ashwagandha at the same time? +
No trial has tested the 2 alone together, though both appear in multi-herb products. Start 1 at a time so you can tell which is doing what.
What is the best herb to reduce cortisol? +
No herb is proven to. A 2022 review of 52 trials found ashwagandha's morning cortisol-lowering effect the most consistent result.
What should you never mix with ashwagandha? +
Our ashwagandha guides cover its interactions in detail. As a rule, ask your prescriber before combining it with any prescription drug, and avoid it in all 3 trimesters of pregnancy.
What is more powerful than ashwagandha? +
Powerful is not measured anywhere. Among stress herbs, ashwagandha already has 1 of the larger trial bases, 77 tagged trials in PubMed.
Is holy basil an adaptogen like ashwagandha? +
Both are called adaptogens in Ayurveda. The label is traditional, and the 2 have very different amounts of human evidence.
Which is better for sleep? +
Ashwagandha has more sleep research, with 15 tagged trials mentioning sleep or insomnia. Holy basil has 1 trial, from 2022, with better self-rated insomnia scores.
Are they safe in pregnancy? +
Neither is recommended. For holy basil, rat and rabbit studies found fertility effects and 0 human pregnancy trials exist.
Which has fewer side effects? +
Both were well tolerated in short trials. Holy basil's cautions are blood sugar and 23 mostly animal fertility records; ashwagandha has its own separate list.
Which one works faster? +
Neither is fast. Holy basil stress trials ran 6 to 8 weeks, and the 2026 ashwagandha arm was measured at 30 and 60 days.
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