Is holy basil the same as the basil I cook with?

No. Sweet basil is Ocimum basilicum. Holy basil, Ocimum tenuiflorum, is a different species with a spicier, clove-like scent, and the clinical research is on holy basil.

Can I take it every day?

Daily use is how it is traditionally taken. The longest trials ran for about 13 weeks, so long-term data are limited, and it is worth checking first if you take regular medicines.

Does holy basil tea work as well as an extract?

I do not know, and nobody does yet. Tea is the traditional and gentler preparation, but the trials used concentrated extracts, so the evidence applies most directly to those.

Will it make me drowsy?

In the 2022 trial, the side effects reported were mostly digestive upset and headaches, and they occurred about as often on placebo as on holy basil (12 events against 10). It is not a sedating herb.

Holy Basil (Tulsi): What It Is, How It Works, and When to Use It

Sarah Burt

Oct 14

7 min read

Holy basil (Ocimum tenuiflorum), known in India as tulsi, is a fragrant Ayurvedic herb traditionally used to support resilience to everyday stress and classed as an adaptogen. In an eight-week trial of 100 stressed adults, a standardised leaf extract at 250 mg a day was linked to a larger fall in perceived stress and in insomnia scores than placebo. It is one of the four herbs in the EarthWise Adrenal Guard tonic.

Close-up of a Holy Basil plant with purple stem and tiny pink flowers against a blurred green garden background

What it is

Holy basil is an aromatic shrub in the mint family (Lamiaceae), native to the Indian subcontinent and now grown across South-East Asia. It is a relative of the sweet basil in your kitchen, but a different species (Ocimum basilicum), with a spicier, clove-like scent and a very different history. You may also see it listed under its older name, Ocimum sanctum.

In India, tulsi is a household plant as much as a medicine. Many homes keep a plant in the courtyard, and it holds a sacred place in Hindu tradition. Ayurveda calls it the "Queen of herbs" and traditionally uses the leaf as a daily tonic, most often as a tea, to support the respiratory, digestive and nervous systems. The leaf is the part used, fresh or dried, and it is traditionally taken as a long-term daily habit.

Two types are most common: Rama (green leaf) and Krishna or Shyama (purple leaf). Many studies do not say which type was used, which is one reason to read the research with some caution.

A buyer's note worth reading. Tulsi tea is widely sold and pleasant to drink, but a cup of tea is a much weaker preparation than the concentrated leaf extracts used in most clinical trials. The best recent trial also used a branded, manufacturer-funded extract. If you are buying a supplement, look for the plant part (leaf), the full Latin name and the extract strength.

The active compounds

Holy basil leaf contains an essential oil rich in eugenol, the compound that gives cloves their scent, alongside phenolic acids such as rosmarinic acid, triterpenes such as ursolic acid, and flavonoids including apigenin and luteolin. As with most whol

e herbs, it is the combination that interests herbalists, more than any single molecule.

Holy basil is usually described as an adaptogen, a herb traditionally taken to help the body cope with sustained stress. It is a gentle, aromatic member of that group, with a warming taste, and it is one of the few adaptogens that people also enjoy simply as a daily tea.

The main proposed mechanism: the stress response. In the 2022 trial described below, people taking the extract had lower cortisol in hair samples after eight weeks (hair cortisol reflects average levels over the previous couple of months) and lower salivary cortisol during a lab stress test. The proposed route is the HPA axis, the hypothalamic-pituitary-adrenal loop that governs the stress response. Animal studies also suggest holy basil constituents influence stress hormones and brain chemistry, including serotonin, dopamine and GABA signalling, though this has not been confirmed in people.

A second, proposed mechanism: blood sugar. Several small trials have reported lower fasting blood glucose in people taking tulsi, and animal work suggests effects on how cells respond to insulin. This is one reason holy basil features in formulas built around steady energy. The human evidence is early (see below).

Other activity. In laboratory studies, holy basil shows antioxidant and anti-inflammatory activity, mostly linked to eugenol and rosmarinic acid. Direct human evidence for these effects is limited.

What the research shows

Holy basil has a long traditional record and a growing but small clinical one. A 2017 systematic review (Jamshidi and Cohen) found 24 human studies with 1,111 participants in total. Only a small minority were rated high quality, and most were small, short (two to 13 weeks) and run in India, so the authors warn the effects may have been overestimated. Here is how the evidence grades.

Evidence: stress, mood and sleep. The best trial is a 2022 randomised, placebo-controlled study (Lopresti and colleagues, Frontiers in Nutrition) of 100 adults aged 18 to 65 who had felt stressed for over a month and had sleep problems. They took 250 mg a day of a standardised holy basil leaf extract for eight weeks. Perceived stress scores fell 37% in the holy basil group against 19% on placebo, and insomnia scores fell 48% against 27%. Hair cortisol was lower at week 8, and cortisol, blood pressure and subjective stress during a lab stress test were lower too. Two earlier trials in the 2017 review also reported reductions of roughly a third to 39% in stress-related symptoms.

Evidence: blood sugar. Eight studies in the 2017 review measured blood glucose, and several reported lower fasting levels. Most were small and short, and some gave tulsi alongside prescribed diabetes medicines, so it is hard to say what the herb itself contributed.

Early evidence: focus and thinking. In a trial of 40 healthy adults, 300 mg a day for four weeks was linked to better attention and cognitive flexibility, while working memory only improved after about two weeks (Sampath and colleagues, 2015, reported in the 2017 review).

Other areas. Small studies have looked at blood pressure, cholesterol and immune markers, with some positive findings, but the quality is low and I would not draw conclusions from them yet.

Sarah's clinical perspective

In clinic I think of holy basil as a herb for the person whose stress sits in the body and the gut as much as the mind: tense, wired, running on coffee, with energy and cravings that swing through the day. It has a warm, slightly spicy character that suits that picture.

I rarely use it alone. In Adrenal Guard it sits with Siberian ginseng, cinnamon and gymnema, herbs traditionally used to support steady energy and healthy blood sugar. In Hormone Harmony it works with ashwagandha, shatavari and chaste tree on the stress side of hormonal wellbeing.

It is a long-game herb. I ask people to give it several weeks, and to look at the basics alongside it: regular meals, light in the morning and a proper wind-down in the evening.

Practical guidance

Dose. Trials have used a wide range. The 2022 trial used 250 mg a day of a standardised leaf extract. Older studies used 300 to 1,000 mg of leaf extract once or twice a day, and much larger amounts of aqueous or whole-plant preparations, from several grams up to 14 g. These are the amounts researchers used, not a dosing instruction for any particular product.

Format. Tea is the traditional and gentlest form, and many people enjoy it as a daily ritual. A liquid extract (tincture) is more concentrated. Standardised capsule extracts match the trial evidence most closely.

Time to effect. Allow four to eight weeks. The trials showing benefit ran for four to eight weeks, and in the focus trial some effects only appeared after the first two weeks.

Timing. There is no firm consensus. Traditional use is regular daily intake, and some trials split the dose between morning and evening.

What it does not replace. Holy basil will not undo the causes of chronic stress. Sleep, regular meals and movement are the foundations, and the herb supports the body alongside those.

For how to take the EarthWise tonic specifically, the dose and full safety information are on the product page.

Common questions

Is holy basil the same as the basil I cook with? No. Sweet basil is Ocimum basilicum. Holy basil, Ocimum tenuiflorum, is a different species with a spicier, clove-like scent, and the clinical research is on holy basil.
Can I take it every day? Daily use is how it is traditionally taken. The longest trials ran for about 13 weeks, so long-term data are limited, and it is worth checking first if you take regular medicines.
Does holy basil tea work as well as an extract? I do not know, and nobody does yet. Tea is the traditional and gentler preparation, but the trials used concentrated extracts, so the evidence applies most directly to those.
Will it make me drowsy? In the 2022 trial, the side effects reported were mostly digestive upset and headaches, and they occurred about as often on placebo as on holy basil (12 events against 10). It is not a sedating herb.

Where holy basil appears in the EarthWise range

Holy basil (listed as Tulsi) is one of the four herbs in Adrenal Guard, Sarah's formula for steady energy, where it sits with Siberian Ginseng, Cinnamon and Gymnema.

It also appears in Hormone Harmony, alongside Ashwagandha, Shatavari and Chaste Tree. (It is also part of the Man-Ease formula within the Reset Program.)

If you are not sure which formula fits, the EarthWise health quiz is the best place to start. Full safety information is on each product page.

When to seek professional support

Holy basil is well tolerated in the studies so far, but the longest ran for only about 13 weeks, so long-term safety data are limited. Check with a practitioner first in these situations:

Pregnancy, breastfeeding or trying to conceive. It is not recommended in pregnancy or breastfeeding because too little is known, and some animal studies have raised questions about fertility.
Blood-thinning medicines or planned surgery. Holy basil may slow clotting. Check first if you take warfarin, aspirin, clopidogrel or similar medicines, and speak to your surgical team about stopping at least two weeks before an operation.
Medication for diabetes or blood pressure. Holy basil may influence blood sugar and blood pressure, so speak to your GP or practitioner first.
Other prescribed medicines. If you take any regular medication, check with your GP or pharmacist before adding a herbal tonic.

Sarah Burt is a registered naturopath, medical herbalist and iridologist with 25+ years of clinical experience. All EarthWise tonics are formulated by Sarah based on her clinical protocols.

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This article is for informational purposes only and is not intended to diagnose, treat or cure any health condition. Always consult a qualified health practitioner before making changes to your health regimen.