Dried Herb & Tea

Holy Basil

Ocimum tenuiflorum

B Limited clinical evidence

Holy basil (tulsi) showed possible benefits for stress and blood sugar in small, low-quality studies. Take care with blood thinners and diabetes medicines.

Sleep, Stress & MoodMetabolism, Weight & Blood Sugar
Holy Basil
Pregnancy⚠ Avoid
Breastfeeding⚠ Avoid
ChildrenUnknown
Drug interactionsInteraction reported
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At a glance

Holy basil (tulsi, Ocimum tenuiflorum) is a basil species used in Ayurveda as an adaptogen to help the body cope with stress. Small human studies suggest possible effects on anxiety, stress and blood sugar, but there are no high-quality studies. It is different from culinary basil (O. basilicum).

Parts used: leaves
Key constituents: Eugenol, Ursolic acid, Rosmarinic acid

Updated: October 24, 2026

Sources and research limitations appear below. The existence of a source does not mean every use has been clinically verified.

What is it used for?

  • B Limited clinical evidence

    Limited clinical evidence: Limited human data; small samples, methodological problems or inconsistent results reduce certainty. Findings do not apply to every product.

    How do we rate evidence levels? →

    Small, lower-quality human studies suggest a possible benefit for anxiety and stress symptoms. No high-quality studies confirm this; a systematic review of 24 clinical studies also calls for larger, well-designed trials. [1][2]

  • B Limited clinical evidence

    Limited clinical evidence: Limited human data; small samples, methodological problems or inconsistent results reduce certainty. Findings do not apply to every product.

    How do we rate evidence levels? →

    Small human studies found lower blood sugar; the studies were small and of limited quality. For this reason, blood sugar may fall too much in people taking diabetes medicine. [1][2]

How is it used?

Tea

The leaf is taken by mouth as a tea or supplement. Oral use has been studied for up to 8 weeks; safety of longer use is unknown and there is no verified dose.

Duration limit: 8 weeks

[1]

Safety & interactions

Duration limit: 56 days

  • Do not use in pregnancy, while breastfeeding or when trying to conceive; high doses reduced successful pregnancy in animals.
  • It may slow blood clotting; do not use it before surgery and tell your doctor.
  • It may lower thyroxine levels; people with an underactive thyroid (hypothyroidism) should not use it.
  • People with type 2 diabetes or taking diabetes medicine should not use it without asking a doctor.
  • Safety beyond 8 weeks of use has not been studied.
[1][2]

Drug interactions

Drug interactions
Medicine / substanceEffectSeverity
Blood thinners and antiplatelet drugs (warfarin, heparin, aspirin, clopidogrel)May increase bruising and bleeding by slowing clotting. Ask your doctor before combining. [1]Moderate
Insulin and sulfonylureas (e.g. glimepiride)Because it may lower blood sugar, combining them could cause hypoglycaemia. [1]Moderate
SedativesIncreased the effect of some sedatives in animal studies; relevance in humans is unknown. [1]Minor

Side effects

  • Nausea
  • Diarrhoea

⚕ When to see a doctor

  • If high fever, shortness of breath or purulent/bloody phlegm develops
  • If symptoms do not improve within 1–2 weeks or worsen
  • If severe abdominal pain, jaundice, rash or allergic reaction occurs

Frequently asked questions

Does tulsi tea help with stress?

Small, lower-quality studies suggest a possible benefit for anxiety and stress symptoms. Without high-quality studies, the effect is not proven.

Is holy basil the same as regular basil?

No. Holy basil is Ocimum tenuiflorum (O. sanctum), while culinary basil is Ocimum basilicum. Tulsi studies cannot be applied to culinary basil.

Does tulsi lower blood sugar?

Small studies found lower blood sugar. If you take diabetes medicine, ask your doctor, as your blood sugar could fall too much.

Can I use tulsi while pregnant?

No. It should not be used in pregnancy, while breastfeeding or when trying to conceive; high doses harmed pregnancy in animal studies.

Does tulsi affect the thyroid?

It may lower thyroxine levels and worsen hypothyroidism. Ask your doctor before using it if you have thyroid disease.

Sources

Source type is not an efficacy rating. A monograph may document traditional use or safety. Claim numbers link to the relevant source; the access date does not indicate professional approval.

  1. Holy BasilMSD Manual Consumer Version (Merck & Co.) · 2025 · Reference bookSource accessed:
  2. The Clinical Efficacy and Safety of Tulsi in Humans: A Systematic Review of the LiteratureEvidence-Based Complementary and Alternative Medicine · 2017 · Systematic reviewSource accessed:

Cite This Page

Holy Basil (Ocimum tenuiflorum). Herbadex — Doğal Şifa Rehberi (2026). https://herbadex.com/en/herb/holy-basil/

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