Holy Basil

A traditional anti-fertility agent and libido enhancer in Ayurveda, Holy Basil (also known as Tulsi) is currently being investigated for these two claims and its general health properties. A good source of dietary Ursolic Acid, which may cause the anti-fertility aspects.

This page features 26 unique references to scientific papers.


All Essential Benefits/Effects/Facts & Information

Holy Basil (also known as Tulsi, or Ocimum sanctum) is an ayurvetic herb which has historically been used to treat a variety of general ailments. It recently has been shown to hold scientific worth in the areas of liver protection and general anti-oxidant activity, as well as being classified as an Adaptogen (reducing the effects of stress on the body).

It is also used as a Testosterone Booster, although no direct evidence exists in humans for this. It has also been demonstrated to hinder reproductive capacity.

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Things To Know

Also Known As

Ocimum sanctum, Green Tulsi, Sacred Basil, Tulsi, Ocimum tenuiflorum

Do Not Confuse With

Thai Basil (a table spice)

Things to Note

  • Many studies not using an ethanol-extract, suggesting the active ingredients may be fat-soluble in nature
  • Probably one of the only testosterone boosting compounds (whether it works or not) that hinders spermatogenesis, possibly related to the Ursolic Acid content

Is a Form Of

Goes Well With

Caution Notice

High doses of holy basil may be anti-fertility in males due to impairing spermatogenesis.

Examine.com Medical Disclaimer

How to Take

Recommended dosage, active amounts, other details

500mg of the leaf extract taken twice daily appears to be recommended for neurological and adaptogenic effects of holy Basil, whereas the only evidence on other health effects or testosterone boosting are done in rats with the dosages of 100-200mg/kg and 500mg/kg respectively. This leads to an estimated human dose of:

  • 1,100-2,200mg for a 150lb person for general health and 5,500mg for testosterone boosting
  • 1,500-2,900mg for a 200lb person for general health and 7,300mg for testosterone boosting
  • 1,800-3,600mg for a 250lb person for general health and 9,100mg for testosterone boosting

These are estimated human dosages based on animal research, and it is unsure if they are the optimal doses for humans.

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Human Effect Matrix

The Human Effect Matrix looks at human studies (it excludes animal and in vitro studies) to tell you what effects holy basil has on your body, and how strong these effects are.

Grade Level of Evidence
Robust research conducted with repeated double-blind clinical trials
Multiple studies where at least two are double-blind and placebo controlled
Single double-blind study or multiple cohort studies
Uncontrolled or observational studies only
Amount of Evidence
? The amount of high quality evidence. The more evidence, the more we can trust the results.
Outcome Magnitude of effect
? The strength of the outcome. Some supplements can have an increasing effect, others have a decrease effect, and others have no effect.
Consistency of research results
? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.
Immunity Minor Very High See study
Appears to induce proliferation of T cytokines and T lymphocytes
Natural Killer Cell Content Minor Very High See study
An increased level of NK cell count has been noted following ingestion of Tulsi leaves
Anxiety Minor Very High See study
A decrease has been noted, but the studies are not overly robust at this moment in time
Blood Glucose Minor Very High See study
May reduce blood glucose, with the potency demonstrated (fairly good) limited by the quality of the evidence currently
Depression Minor Very High See study
A decrease in depressive symptoms during generalized anxiety disorder has been noted

1Sources and Composition

1.1. Usage

Holy Basil, also known as Tulsi, is an Ayurvetic plant traditionally used for general health and a long life.[1] Traditionally, the active ingredient is an oil extract of the leaves, which although traditionally used for a myriad of reasons is most commonly regonized for anti-stress and pro-vitality properties.[2]

Its herbal name is Ocimum Tenuiflorum, although Ocimum Sanctum is commonly seen as a synonym; these two terms as well as Holy Basil and Tulsi are all interchangeable in regards to supplementation.

1.2. Composition

As a herbal supplement, Holy Basil contains a few molecules. These include:


2.1. Stress and Anxiety

Some components of ocimum sanctum, namelt ocimarin and the ocimumosides A and B, appear to exert antistress activity when given to rats at the dose of 40mg/kg.[5]

In otherwise healthy subjects given ocimum sanctum twice daily (500mg each time after meals) over the course of two months, supplementation appeared to reduce symptoms of generalized anxiety disorders as assessed by the BPRS.[7]

3Inflammation and Immunology

One human trial noted that after 4 weeks consumption of 300mg ethanolic extract of Tulsi leaves, that participants experienced an increase in some cytokines associated with the immune system; interferon-y (IFN-y), interleukin-4 (IL-4), as well as T-helper cells and NK-cells.[8] No influence on Cytotoxic T-cells or B-cells were noted in this study. When cells were isolated from subjects and pro-inflammatory chemicals were added (LPS, phytohaemagglutinin) the immune cells of the Tulsi group were more effective in mounting an adaptive immune response via IFN-y and T-helper cells and NK-cells.

These immunomodulatory effects may be secondary to the flavonoid content of Tulsi.[9]

4Interactions with Hormones

4.1. Testosterone

The only noted effects of Holy Basil on testosterone levels are from a rabbit study ingesting 2g of Holy Basil per day.[10] This study and previous ones[11][12] noted reductions in sperm count and reproductive potential, which parallels studies with the component of Holy Basil Ursolic Acid.[13][14]

A possible explanation being a possible androgenic analogue in Holy Basil which increases testosterone sufficiently enough to repress luteinizing and follicle-stimulating hormones significantly.[10]

5Peripheral Organ Systems

5.1. Liver

Holy Basil seems to be effective in preventing toxin-induced damage to the liver[15][16] in doses of 100-200mg/kg bodyweight. These protective effects are due to a supposed membrane stabilizing effect of Holy Basil constituents.[17]

Synergism was noted on hepatoprotection when paired with Milk Thistle.[17]

Holy Basil, like other adaptogenic compounds, can reduce cadmium build-up in the body[18] and protect the body from already placed cadmium toxicity[19] and reverse build-up.[20] The proposed mechanism was anti-oxidant flavonols also acting as metal chelators or otherwise alleviating oxidative stress of cadmium enough for other chelators to act before damage could occur.[18]

6Safety and Toxicity

6.1. General

Toxicity has been reported for the oil extract of Holy Basil (which contains 70+/-3% eugenol content[21]) and has been found to be 42.5ml/kg bodyweight.[22][23] Whereas the dry plant extract with a normal eugenol content has an LD50 of between 4600-6400mg/kg bodyweight in research animals.[8][2][24]

Scientific Support & Reference Citations


  1. Singh S, Majumdar DK Evaluation of antiinflammatory activity of fatty acids of Ocimum sanctum fixed oil . Indian J Exp Biol. (1997)
  2. Bhargava KP, Singh N Anti-stress activity of Ocimum sanctum Linn . Indian J Med Res. (1981)
  3. Ursolic Acid, a Pentacyclin Triterpene, Potentiates TRAIL-induced Apoptosis through p53-independent Up-regulation of Death Receptors
  4. Prakash P, Gupta N Therapeutic uses of Ocimum sanctum Linn (Tulsi) with a note on eugenol and its pharmacological actions: a short review . Indian J Physiol Pharmacol. (2005)
  5. Gupta P, et al Constituents of Ocimum sanctum with antistress activity . J Nat Prod. (2007)
  6. Hakkim FL, Shankar CG, Girija S Chemical composition and antioxidant property of holy basil (Ocimum sanctum L.) leaves, stems, and inflorescence and their in vitro callus cultures . J Agric Food Chem. (2007)
  7. Bhattacharyya D1, et al Controlled programmed trial of Ocimum sanctum leaf on generalized anxiety disorders . Nepal Med Coll J. (2008)
  8. Mondal S, et al Double-blinded randomized controlled trial for immunomodulatory effects of Tulsi (Ocimum sanctum Linn.) leaf extract on healthy volunteers . J Ethnopharmacol. (2011)
  9. Mukherjee R, Dash PK, Ram GC Immunotherapeutic potential of Ocimum sanctum (L) in bovine subclinical mastitis . Res Vet Sci. (2005)
  10. Sethi J, et al Effect of tulsi (Ocimum Sanctum Linn.) on sperm count and reproductive hormones in male albino rabbits . Int J Ayurveda Res. (2010)
  11. Seth SD, Johri N, Sundaram KR Antispermatogenic effect of Ocimum sanctum . Indian J Exp Biol. (1981)
  12. Khanna S, Gupta SR, Grover JK Effect of long term feeding of tulsi(Ocimum sanctum Linn) on reproductive performance of adult albino rats . Indian J Exp Biol. (1986)
  13. Chattopadhyay D, et al A potent sperm motility-inhibiting activity of bioflavonoids from an ethnomedicine of Onge, Alstonia macrophylla Wall ex A. DC, leaf extract . Contraception. (2005)
  14. Ursolic acid generates symplasts in rat spermatogenic clones
  15. Ubaid RS, et al Effect of Ocimum sanctum (OS) leaf extract on hepatotoxicity induced by antitubercular drugs in rats . Indian J Physiol Pharmacol. (2003)
  16. Hepatoprotective activity of Ocimum sanctum leaf extract against paracetamol induced hepatic damage in rats
  17. Lahon K, Das S Hepatoprotective activity of Ocimum sanctum alcoholic leaf extract against paracetamol-induced liver damage in Albino rats . Pharmacognosy Res. (2011)
  18. Bharavi K, et al Prevention of cadmium bioaccumulation by herbal adaptogens . Indian J Pharmacol. (2011)
  19. Ramesh B, Satakopan VN Antioxidant Activities of Hydroalcoholic Extract of Ocimum sanctum Against Cadmium Induced Toxicity in Rats . Indian J Clin Biochem. (2010)
  20. Bharavi K, et al Reversal of Cadmium-induced Oxidative Stress in Chicken by Herbal Adaptogens Withania Somnifera and Ocimum Sanctum . Toxicol Int. (2010)
  21. Padalia RC, Verma RS Comparative volatile oil composition of four Ocimum species from northern India . Nat Prod Res. (2011)
  22. Kumar A, et al Chemical composition, antifungal and antiaflatoxigenic activities of Ocimum sanctum L. essential oil and its safety assessment as plant based antimicrobial . Food Chem Toxicol. (2010)
  23. Singh S, Taneja M, Majumdar DK Biological activities of Ocimum sanctum L. fixed oil--an overview . Indian J Exp Biol. (2007)
  24. Devi PU, Ganasoundari A Radioprotective effect of leaf extract of Indian medicinal plant Ocimum sanctum . Indian J Exp Biol. (1995)
  25. Bhat J, et al In vivo enhancement of natural killer cell activity through tea fortified with Ayurvedic herbs . Phytother Res. (2010)
  26. 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)

(Common misspellings for Holy Basil include basl, holi, tuls, tulsy, ocimium, ocumim)

(Editors who contributed to this page include , )