Holy Basil (Tulsi): Benefits, Tea, Dosage & Side Effects

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Holy basil tastes pungent and a little bitter,2 sharper than the sweet basil in a pesto, and the reason is in the leaf's oil. The oil in holy basil leaves is mostly eugenol, the same compound that gives clove oil its bite, while sweet basil's oil is mostly methyl chavicol and linalool.5 In India it's called tulsi, and families have grown it beside their homes and temples for generations.26

Today holy basil is best known as an adaptogen, an herb that helps your body adapt to stress, and it supports a healthy cortisol rhythm.7 Human trials have tested it for stress, sleep, blood sugar, immunity and focus.1

I describe holy basil as a gentle adaptogen that calms without sedating.2 I drink it daily as a tea, often together with turmeric, and in our house we also diffuse it to reduce stress.289

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What is holy basil (tulsi)?

Two types grow under the name Ocimum tenuiflorum: Rama or Sri tulsi, with green leaves, and Krishna or Shyama tulsi, with purplish leaves. A third, Vana or wild tulsi, is a related species, Ocimum gratissimum, that's used the same way.1 On my show, I've pointed out that holy basil often has a purple tint to it, sometimes all purple and sometimes green with a little purple mixed in.11 Krishna tulsi carries more phenolic compounds than the wild type.6

Holy basil leaves carry ocimumosides, compounds named for the plant's genus that researchers have studied for their effect on stress hormones, covered in the cortisol section below.12

A short history of holy basil

Within Ayurveda, tulsi is known as "The Incomparable One," "Mother Medicine of Nature" and "The Queen of Herbs."6 The Indian Materia Medica describes the leaves for bronchitis, rheumatism and fever, and traditional healers have used the tea for stomach and liver complaints and the leaf juice as drops for earache.1 Many Indian households keep a tulsi plant in a courtyard pot, and Ayurvedic practitioners recommend regular tulsi tea as part of a healthy daily routine.6

In the language of Ayurvedic energetics, here's holy basil's profile:2

What is holy basil good for?

Holy basil benefits, ranked by evidence

Ranked by the human evidence, holy basil does the most for stress, with encouraging results for sleep, blood sugar and anxiety, and early findings for immunity, focus and gum health.

Does holy basil help with stress and anxiety?

The newest trial ran in Australia. Researchers gave 100 adults who'd felt stressed for more than a month and slept poorly either 125 mg of a standardized holy basil leaf extract twice a day (250 mg a day) or a placebo for 8 weeks; neither the people nor the researchers knew who got what, and 85 finished. Scores on the Perceived Stress Scale fell 37% with holy basil and 19% with placebo, an average drop of 8.02 points against 4.28, and the gap between the groups was significant from week 6.3 Scores on a general mood questionnaire didn't differ between the groups.3

Source: Lopresti et al., 2022, results tables.3

An earlier placebo-controlled trial in Lucknow, India, enrolled 158 adults with at least three stress symptoms, such as exhaustion, forgetfulness or poor sleep. They took a standardized whole-plant extract supplying 1,200 mg of actives a day (one capsule after breakfast and two after dinner) or a placebo for 6 weeks, and 150 were analyzed. The two groups improved alike at weeks 2 and 4, and by week 6, total self-rated symptom scores had dropped 9.58 points with holy basil, from 13.27 to 3.69, against 5.84 points with placebo, from 12.58 to 6.75. Forgetfulness, exhaustion, recent sleep problems and recent sexual problems improved more than on placebo, and neither group reported side effects.13

In a hospital study of 35 adults with generalized anxiety disorder, 500 mg of leaf extract twice a day after meals for 60 days lowered anxiety, stress and depression scores and improved attention; the study had no comparison group.14 A randomized trial of holy basil tea also found less anxiety, covered in the tea section below.15 I recommend holy basil along with lavender and chamomile for anxiety.22 If you take medicine for anxiety or depression, keep taking it as prescribed, and see the interaction check in the safety section.

Holy basil tea is on the eat-freely list in the Calm phase of my Stress, Anxiety & Mood Protocol, beside chamomile and lemon balm tea, and holy basil is one of the protocol's honorable mentions among calming herbs.23 The herb works best inside the rest of that plan: protein at breakfast, steady meals, morning light, slow breathing exercises and a screen curfew at night.23 Our guide to natural remedies for anxiety covers more.

The protocol also turns to Jesus's teaching on worry in Matthew 6,23 which ends with words worth carrying into a stressful week: "Take therefore no thought for the morrow: for the morrow shall take thought for the things of itself. Sufficient unto the day is the evil thereof." (Matthew 6:34)

Does holy basil lower cortisol?

Cortisol is your main stress hormone, and your body needs it. The trouble starts when stress keeps it high day after day, which is where adaptogens such as ashwagandha, rhodiola and holy basil come in.

In the Australian trial, hair cortisol, a record of the weeks before the sample was taken, measured 269.68 pg per 50 mg of hair in the holy basil group at week 8, against 789.89 in the placebo group. Samples were taken only at the end, and hair grown before the trial already differed between the groups.3 In a lab stress test given to 81 of the participants, saliva cortisol, blood pressure and stress ratings ran lower in the holy basil group across the whole session, though that group started the test a little lower on blood pressure and stress ratings.3 In a 30-day placebo-controlled trial of 40 healthy young adults, saliva cortisol fell in the holy basil group, though the change didn't differ significantly from placebo.171

Here's how holy basil may calm the stress response, step by step:

Holy basil and adrenal fatigue

Adrenal fatigue is the name many people use for the drained, wired-at-night pattern that long stress can leave behind, and the cortisol rhythm underneath it is real, measurable and improvable. Mainstream endocrinology doesn't use the term as a diagnosis: a 2016 systematic review of 58 studies, which found conflicting results across the cortisol tests used, concluded there was no substantiation that it is an actual medical condition.24 Whatever name you use, the daily rhythm can be tested.

On my show, I've recommended holy basil for adrenal fatigue because it helps balance cortisol levels.22 For the pattern of feeling exhausted in the morning and wired at night, my advice is to drink holy basil tea through the morning, get a cortisol test and take some adaptogens.25 If your test comes back very low, see the safety section first. If you're always tired, our guide walks through the cortisol rhythm and the other common causes, and these foods that lower cortisol round out the plate.

Does holy basil help you sleep?

Holy basil improved sleep scores in stressed adults with poor sleep. In the 8-week Australian trial, scores on the Athens Insomnia Scale, a questionnaire about falling asleep, staying asleep and how rested you feel, fell from 11.29 to 5.87 with 250 mg a day of holy basil extract, a 48% drop, against 12.15 to 8.91 with placebo, a 27% drop; the difference was significant at week 8.3 A wrist sleep tracker showed no difference between the groups in total sleep time.3 In the Indian trial, recent sleep problems eased more on holy basil than on placebo, with the symptom score falling from 1.30 to 0.27 against 1.49 to 0.84.13

In the two stress trials, drowsiness wasn't among the side effects reported, and side effects overall were about as common as on placebo.313 As I've explained on my show, herbs like ashwagandha, reishi and tulsi tea lower cortisol, and when cortisol comes down, melatonin can rise.26 The trials measured sleep with questionnaires rather than melatonin, and those scores improved.3

I like holy basil as a morning tea, and you can drink it in the evening too, when it can help your sleep at night.27 My Deep Sleep Protocol puts holy basil tea on the eat-freely list in its Deepen phase and builds the rest of the plan: the same wake time every day, morning sunlight, caffeine only before noon and a real wind-down routine.28 For more options, see these natural sleep aids.

Can holy basil lower blood sugar?

In that trial in India, adults with type 2 diabetes took dried holy basil leaf powder for one period and placebo leaves for another, so each person tried both, and they weren't told which was which.4 According to the 2017 review, the trial enrolled 40 adults aged 41 to 65, who took 2.5 grams of leaf powder each morning before a meal, with spinach leaf powder as the placebo.1 On holy basil, fasting blood sugar was 21.0 mg/dL lower (17.6%) and after-meal blood sugar 15.8 mg/dL lower (7.3%), urine glucose followed the same trend, and total cholesterol dipped slightly.4

A pilot study looked at insulin too. In 30 overweight or obese young adults, 250 mg of leaf extract twice a day on an empty stomach for 8 weeks improved triglycerides, LDL, HDL, body mass index, insulin and insulin resistance from where they started, and HDL rose significantly more than in an untreated comparison group; people knew which group they were in.18 Researchers have proposed that eugenol, holy basil's main aromatic compound, slows the breakdown of carbohydrates, a mechanism that hasn't been tested in people.1

In my herb guide, I rank blood sugar second among holy basil's uses by strength of research, after stress and anxiety.2 Use it as one support inside a full plan: see what normal blood sugar looks like, build your meals around protein, fiber and healthy fats, and use the free Insulin Resistance & Prediabetes protocol or Type 2 Diabetes protocol. If you take diabetes medicine, read the interaction check in the safety section before you start.

Holy basil (tulsi) tea: benefits and how to make it

That tea trial ran in Japan, in 44 adults with thyroid cancer during radioactive iodine treatment. Half drank a cup of holy basil tea after each meal for 4 days, each cup made from 2.0 grams of dried leaf steeped 5 minutes in 180 mL (about ¾ cup) of boiling water, and half drank the same amount of water; people knew which they drank, and 42 were analyzed. On a standard anxiety questionnaire, in-the-moment anxiety fell 3.39% on average with the tea and rose 5.38% with water, and longer-standing anxiety fell 9.03% with the tea, against almost no change with water. Saliva levels of bacteria linked to tooth decay fell 15.61% on average in the tea group and rose 7.52% in the water group.15

Here's how to make a cup:

1. Measure 1 to 2 teaspoons of dried holy basil leaves into a mug or teapot.2

2. Pour a cup of just-boiled water over the leaves.15

3. Steep 5 to 10 minutes, covered, then strain.2

4. Sweeten with a teaspoon of raw honey if you like; Manuka honey works too.

5. Drink 1 to 3 cups a day, in the morning, the afternoon or the evening.227

For a creamy cup, add a splash of coconut milk or goat milk.

My anti-inflammatory golden tea pairs holy basil with fresh turmeric and ginger: simmer the turmeric and ginger for 10 minutes, then add holy basil and steep 5 minutes more, and drink 1 to 2 cups a day between meals.29 For another cup to rotate in, try this turmeric tea.

How much holy basil should you take a day?

These are the amounts the human studies used:

Beyond tea and extract, I suggest a few fresh leaves a day, chewed or tossed into a salad, or a tincture at 2 to 4 mL twice a day.2 Ayurvedic physicians in one survey gave 2 to 25 fresh leaves a day, about 321 to 2,621 mg, usually as juice.30

For a full plan to wrap around holy basil, see our guide to chronic stress.

Holy basil essential oil

Ayurvedic healers have used the essential oil distilled from holy basil to help the body adapt to stress.10 My suggestions: diffuse a few drops during times of stress, add 1 drop a day to a favorite recipe, or for the skin, mix 2 or 3 drops into a teaspoon of coconut oil after testing a drop on a small patch of skin, since it can cause a rash in some people.10 For dilutions and storage, see essential oil safety and this guide to carrier oils.

How to choose a holy basil supplement

Use this checklist when you buy capsules or tea:

• The species on the label, Ocimum tenuiflorum or Ocimum sanctum, the plant in the trials on this page1

• The part and the extract named, leaf or whole plant, the two forms tested in the stress trials313

• A stated amount of active compounds, the way the trial extracts were standardized313

• Third-party testing for purity, with results the maker will share

• Organic dried leaf for tea, on its own or blended with turmeric or ginger

Holy basil vs. sweet basil and Thai basil: what's the difference?

Holy basil and sweet basil are cousins in the same genus with different chemistry. In the distilled oils of cultivars grown in northern India, green and purple holy basil were 67.4% and 72.8% eugenol, while two sweet basil cultivars were mostly methyl chavicol (68.0% and 64.9%) and linalool (21.9% and 25.6%).5 That's why holy basil smells and tastes sharper, and why basil essential oil from sweet basil is a different oil from holy basil oil.

Thai basil, a variety of sweet basil, is Ocimum basilicum var. thyrsiflora.31 Holy basil, Ocimum tenuiflorum, is the one tested in the trials on this page,1 and its fresh leaves can go into food too.2

Holy basil side effects and who should skip it

The safety record in people is reassuring. In the Australian trial, 83% of participants reported no side effects at all; the holy basil group reported 12 side effects and the placebo group 10, mostly digestive upset or headache, and one person on holy basil withdrew because of agitation.3 Across the 24 studies in the 2017 review, one reported short-lived mild nausea; the longest ran 13 weeks, and the reviewers judged daily use safe given tulsi's long traditional use.1 In rodent toxicity tests, single doses of leaf extract up to 2,000 mg per kilogram of body weight caused no harmful signs or deaths in mice, and 800 mg per kilogram a day for 28 days caused no changes in blood counts, blood chemistry or organs in rats.34

I advise avoiding holy basil in pregnancy or when you're trying to conceive.2 The reason comes from animal studies. In a 1969 screening study in rats, a water extract of the leaves showed activity against implantation, the step where a fertilized egg attaches to the uterus.35 In male rabbits, 2 grams of fresh leaves a day for 30 days lowered sperm count and changed reproductive hormones,36 an amount researchers have calculated equals about 48 to 80 grams of leaves a day for a 60-kilogram person,30 and in male rats, a solvent extract of the leaves made in the lab lowered sperm count and movement, effects that returned to normal 2 weeks after it was stopped.37 No human study has looked at pregnancy or fertility, and none has looked at breastfeeding.

See natural blood thinners for other foods and herbs that affect clotting.

The bottom line

Holy basil: frequently asked questions

References

1. 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;2017:9217567. doi:10.1155/2017/9217567
2. Axe J. Top 50 Healing Herbs & Essential Oils: A Field Guide to God's Pharmacy. DrAxe.com protocol; 2026 (Stress, Sleep & Adaptogens: Holy Basil entry).
3. Lopresti AL, Smith SJ, Metse AP, et al. A randomized, double-blind, placebo-controlled trial investigating the effects of an Ocimum tenuiflorum (Holy Basil) extract (HolixerTM) on stress, mood, and sleep in adults experiencing stress. Front Nutr. 2022;9:965130. doi:10.3389/fnut.2022.965130
4. Agrawal P, Rai V, Singh RB. Randomized placebo-controlled, single blind trial of holy basil leaves in patients with noninsulin-dependent diabetes mellitus. Int J Clin Pharmacol Ther. 1996;34(9):406-9.
5. Padalia RC, Verma RS. Comparative volatile oil composition of four Ocimum species from northern India. Nat Prod Res. 2011;25(6):569-75. doi:10.1080/14786419.2010.482936
6. Cohen MM. Tulsi - Ocimum sanctum: A herb for all reasons. J Ayurveda Integr Med. 2014;5(4):251-9. doi:10.4103/0975-9476.146554
7. Axe J, Cole W. Heal Your Cells. Avery; 2026. ISBN 9798217181353 (adaptogens: holy basil and cortisol rhythms).
8. Axe J. The Truth About Cortisol Face and The Exact Steps To Fix It. The Dr. Josh Axe Show. 2026, at 33:21.
9. Axe J, Rubin J. The Biblio Diet. Hachette Book Group; 2025. ISBN 9781546008439 (herbs: holy basil).
10. Axe J. Ancient Remedies: Secrets to Healing with Herbs, Essential Oils, CBD, and the Most Powerful Natural Medicine in History. Little, Brown Spark; 2021 ("The Power of Essential Oils": holy basil oil).
11. Axe J. 8 Adaptogen Herbs to Heal Adrenals and Reduce Stress. The Dr. Axe Show. 2017, at 4:39.
12. Gupta P, Yadav DK, Siripurapu KB, et al. Constituents of Ocimum sanctum with antistress activity. J Nat Prod. 2007;70(9):1410-6. doi:10.1021/np0700164
13. Saxena RC, Singh R, Kumar P, et al. Efficacy of an Extract of Ocimum tenuiflorum (OciBest) in the Management of General Stress: A Double-Blind, Placebo-Controlled Study. Evid Based Complement Alternat Med. 2012;2012:894509. doi:10.1155/2012/894509
14. Bhattacharyya D, Sur TK, Jana U, et al. Controlled programmed trial of Ocimum sanctum leaf on generalized anxiety disorders. Nepal Med Coll J. 2008;10(3):176-9.
15. Nomura K, Nakayama M, Okizaki A. Benefits of basil tea for patients with differentiated thyroid cancer during radioiodine therapy: A randomized controlled trial. Heliyon. 2023;9(10):e20691. doi:10.1016/j.heliyon.2023.e20691
16. Mondal S, Varma S, Bamola VD, et al. Double-blinded randomized controlled trial for immunomodulatory effects of Tulsi (Ocimum sanctum Linn.) leaf extract on healthy volunteers. J Ethnopharmacol. 2011;136(3):452-6. doi:10.1016/j.jep.2011.05.012
17. Sampath S, Mahapatra SC, Padhi MM, et al. Holy basil (Ocimum sanctum Linn.) leaf extract enhances specific cognitive parameters in healthy adult volunteers: A placebo controlled study. Indian J Physiol Pharmacol. 2015;59(1):69-77.
18. Satapathy S, Das N, Bandyopadhyay D, et al. Effect of Tulsi (Ocimum sanctum Linn.) Supplementation on Metabolic Parameters and Liver Enzymes in Young Overweight and Obese Subjects. Indian J Clin Biochem. 2017;32(3):357-363. doi:10.1007/s12291-016-0615-4
19. Gupta D, Bhaskar DJ, Gupta RK, et al. A randomized controlled clinical trial of Ocimum sanctum and chlorhexidine mouthwash on dental plaque and gingival inflammation. J Ayurveda Integr Med. 2014;5(2):109-16. doi:10.4103/0975-9476.131727
20. Jothie Richard E, Illuri R, Bethapudi B, et al. Anti-stress Activity of Ocimum sanctum: Possible Effects on Hypothalamic-Pituitary-Adrenal Axis. Phytother Res. 2016;30(5):805-14. doi:10.1002/ptr.5584
21. Nadar BG, Usha GV, Lakshminarayan N. Comparative Evaluation of Efficacy of 4% Tulsi Extract (Ocimum sanctum), Fluoridated and Placebo Dentifrices against Gingivitis and Plaque among 14-15 years School Children in Davangere City, India - A Triple Blinded Randomized Clinical Trial. Contemp Clin Dent. 2020;11(1):67-75. doi:10.4103/ccd.ccd_109_19
22. Axe J. Holy Basil for Anxiety and 6 Other Health Perks. The Dr. Axe Show. 2017, at 2:05 and 2:39.
23. Axe J. Stress, Anxiety & Mood Protocol. DrAxe.com protocol; 2026 (Phase 2, Calm; p. 18, "Top 8 calming nutrients & herbs," honorable mentions; "Jesus on worry: Matthew 6").
24. Cadegiani FA, Kater CE. Adrenal fatigue does not exist: a systematic review. BMC Endocr Disord. 2016;16(1):48. doi:10.1186/s12902-016-0128-4
25. Axe J. 33 Minutes to HEAL Your Hormones and Feel ENERGIZED Again | Cortisol | Dr. Josh Axe. The Dr. Josh Axe Show. 2026, at 29:15 and 31:11.
26. Axe J. Top 10 Worst Health Trends (That Everyone Thinks Are Healthy). The Dr. Josh Axe Show. 2026, at 17:15.
27. Axe J. 7 Science-Backed Ways to Lower Your Cortisol Fast. The Dr. Josh Axe Show. 2026, at 29:24.
28. Axe J. Deep Sleep Protocol. DrAxe.com protocol; 2026 ("The 4-phase sleep protocol": Anchor, Wind-Down, Deepen, Protect).
29. Axe J. The Cancer Support Protocol: A Root-Cause Approach. DrAxe.com protocol; 2026 (p. 18, "Two daily drinks": the anti-inflammatory golden tea).
30. Narayana DB, Manohar R, Mahapatra A, et al. Posological Considerations of Ocimum sanctum (Tulasi) as per Ayurvedic Science and Pharmaceutical Sciences. Indian J Pharm Sci. 2014;76(3):240-5.
31. Avetisyan A, Markosian A, Petrosyan M, et al. Chemical composition and some biological activities of the essential oils from basil Ocimum different cultivars. BMC Complement Altern Med. 2017;17(1):60. doi:10.1186/s12906-017-1587-5
32. Singh S, Rehan HM, Majumdar DK. Effect of Ocimum sanctum fixed oil on blood pressure, blood clotting time and pentobarbitone-induced sleeping time. J Ethnopharmacol. 2001;78(2-3):139-43. doi:10.1016/s0378-8741(01)00336-1
33. Panda S, Kar A. Ocimum sanctum leaf extract in the regulation of thyroid function in the male mouse. Pharmacol Res. 1998;38(2):107-10. doi:10.1006/phrs.1998.0338
34. Gautam MK, Goel RK. Toxicological Study of Ocimum sanctum Linn Leaves: Hematological, Biochemical, and Histopathological Studies. J Toxicol. 2014;2014:135654. doi:10.1155/2014/135654
35. Vohora SB, Garg SK, Chaudhury RR. Antifertility screening of plants. 3. Effect of six indigenous plants on early pregnancy in albino rats. Indian J Med Res. 1969;57(5):893-9.
36. Sethi J, Yadav M, Sood S, et al. Effect of tulsi (Ocimum Sanctum Linn.) on sperm count and reproductive hormones in male albino rabbits. Int J Ayurveda Res. 2010;1(4):208-10. doi:10.4103/0974-7788.76782
37. Ahmed M, Ahamed RN, Aladakatti RH, et al. Reversible anti-fertility effect of benzene extract of Ocimum sanctum leaves on sperm parameters and fructose content in rats. J Basic Clin Physiol Pharmacol. 2002;13(1):51-9. doi:10.1515/jbcpp.2002.13.1.51
38. Axe J. How to Heal PCOS & Boost Fertility Naturally (Diet, Herbs, & Exercise Plan). The Dr. Josh Axe Show. 2025, at 22:13 and 23:13.

Dr. Josh Axe, DC, DNM, CNS

Doctor of Natural Medicine · Founder, DrAxe.com

Dr. Axe is a certified doctor of natural medicine, clinical nutritionist, and multiple New York Times bestselling author. He has spent 20+ years in clinical practice helping people heal at the root cause and founded one of the most-visited natural-health platforms in the world.

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This article is for educational purposes. See our medical disclaimer.