Dried Fruit
The crude herbal drug, frequently substituted with the visually similar fruit of a different plant, Pedalium murex — see Taxonomy for details.
Traditional · Crude Drug
Sexual Health · Species-Substitution Risk
Biological Overview
Tribulus is a hairy annual herb (10–50 cm) with sprawling stems and small yellow flowers. Its distinctive fruit is a capsule of five radiating, spine-covered carpels — the resemblance to a five-pointed Maltese cross gives the plant its French name, Croix de Malte.
Life CycleAnnual herb
HabitatWorldwide, sandy/waste ground
Common AdulterantPedalium murex
Marker CompoundProtodioscin
Botanical Classification
Taxonomy & Identification
- Latin Name
- Tribulus terrestris L.
- Family
- Zygophyllaceae
- Common Names
- Tribulus, Puncture Vine
- Other Names
- Maltese Cross, Gokshura, Jili
- Parts Used
- Fruits; root or seed extracts
- Habitat
- Worldwide, including southern France, Corsica
From Ancient Aphrodisiac to Gym Supplement
History & the Testosterone Myth
Tribulus has a long traditional history: in Arab and Chinese medicine for skin irritation, insufficient lactation, eye itching, and urinary or reproductive complaints; in India, as Gokshura, a recognized Ayurvedic diuretic and aphrodisiac used in numerous classical preparations. In the United States, it became popular among bodybuilders aiming to increase muscle mass.
That bodybuilding reputation is the central tension of this plant's modern research history. Early animal and small human studies suggested a testosterone-boosting effect, fueling a marketing narrative that persists today. But as larger, controlled human trials accumulated, that specific claim did not hold up — see the timeline.
⚠ Two Separate Questions, Two Different Answers
Does Tribulus raise testosterone? Mostly no. Does it help libido and erectile function? There's real, if modest, support for that — through a different mechanism entirely. Both threads are covered honestly throughout this monograph.
The Key Molecule
Protodioscin — Deep Dive
The specific steroidal saponin most often credited with Tribulus's pro-erectile effect — and the compound at the center of the testosterone debate.
🧬
The Plant's Signature Saponin
Protodioscin is the steroidal saponin specifically credited with the plant's anabolic and pro-erectile reputation.[1]
🩸
Nitric Oxide, Not Hormones
In rabbits, Tribulus extract improves erectile function through a mechanism involving nitric oxide synthase, inducing concentration-proportional relaxation of the corpus cavernosum and increasing intracavernosal pressure.
🐰
Validated in Animal Models
An aqueous fruit extract improves sexual function in male rats, tending to validate the plant's traditional use.[20]
👤
One Real Clinical Benefit: Fertility
A clinical study found an effect superior to placebo against oligozoospermia, one of the principal causes of male infertility.
⚠ A Steroid Precursor That Doesn't Behave Like One
Protodioscin is structurally related to testosterone precursors — but the clinical evidence for a hormonal effect is weak.
Tribulus contains steroidal saponins that are structurally precursors of testosterone, which is part of why the testosterone-boosting claim took hold. But controlled human trials largely fail to show a meaningful testosterone increase in men with normal baseline levels — the real, reproducible effect appears to run through the nitric oxide pathway instead. See Mode of Action.
Available Forms
Parts Used & Available Forms
Commercial extracts are commonly standardized to saponin content.
Standardized Saponin Extract
Root, seed, or fruit extracts standardized to saponin content (commonly 40–45%), the form used in the Bulgarian Tribestan formulation and most modern clinical trials.
Standardized Extract
Clinical Dosimetry
Dosages
Documented across the human trials reviewed in a 2025 systematic review, plus the standardized extract used in the largest erectile-dysfunction trial.
Doses and outcomes vary considerably between trials. Confirm dosing with a healthcare provider — and verify the product's botanical authenticity given the documented substitution risk with Pedalium murex.
Phytochemistry
Composition
A saponin-dominant profile, with the fruit's steroidal glycosides at the center of nearly every documented effect.
Steroidal Saponins
ProtodioscinPrincipal furostanol-type steroidal saponin
Major
Furostanol Saponins (General)Commercial extracts standardized to 40–45% content
Present
Other Constituents
Testosterone-Precursor SteroidsStructural precursors present in the fruit
Present
AlkaloidsPotentially toxic at high exposure — see Safety
Caution
💪
Anabolic & Pro-Erectile (Protodioscine)
Stimulates spermatogenesis via testosterone-precursor steroids.[1]
🧪
Believed to Raise LH
Thought to increase luteinizing hormone levels, a mechanism proposed to explain downstream testosterone effects.
💧
Diuretic & Anti-Lithiasic
Diuretic, anti-lithiasic (against kidney stone formation), anti-inflammatory, and antibiotic properties documented.
🇧🇬
Bulgarian Tribestan Studies
Clinical research on a standardized Bulgarian extract (Tribestan) covering over 200 patients reported libido improvement in 85% of patients with low libido after 30 days and 94% after 60 days, with increased testosterone reported specifically in those with low baseline levels.[7]
🐇
Erectile Function via Nitric Oxide
In rabbits, improves erectile function via a nitric oxide synthase-dependent mechanism, with concentration-proportional corpus cavernosum relaxation and increased intracavernosal pressure and cAMP.[18]
👶
Effective Against Oligozoospermia
A double-blind clinical study showed an effect superior to placebo against oligozoospermia, a principal cause of male infertility.[19]
🍯
Antidiabetic
Inhibits human pancreatic amylase in vitro, relevant to post-meal blood glucose control.[2]
🦠
Antifungal
Eight steroid saponins show potent activity against fluconazole-resistant fungal pathogens.[3]
🔥
Anti-Inflammatory
Inhibits cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS).[4]
📉
Testosterone Response Depends on Baseline Levels
Stimulates testosterone only when levels are below normal — not in subjects with normal baseline levels.[7]
🩸
Works Through Nitric Oxide, Not Androgens
Does not appear to raise testosterone in men, with its observed effects better explained by nitric oxide activity.[8]
📉
Body Composition Findings in Resistance Training
An 8-week randomized trial (3.21 mg/kg/day, 45% saponins) found no improvement in body composition or performance in resistance-trained men; ineffective at raising plasma testosterone even combined with androstenedione and DHEA.[10]
📉
Androgen Levels in Healthy Young Men
Tribulus extracts do not increase androgen levels in men, per a study directly testing this question.[11]
Clinical Applications
Clinical Indications
Indications that hold up reasonably well, set against the one that most often doesn't.
❤️
Sexual & Reproductive Function
Best-Supported Use
❓
Testosterone & Muscle Mass
Marketed Heavily, Poorly Supported
🌿
Traditional Use
Pre-Modern Indications
- Skin irritation, insufficient lactation, eye itching (Chinese medicine).
- Urinary or reproductive disorders in men and women (Chinese medicine).
- Gokshura preparations as a diuretic and aphrodisiac (Ayurveda).
Pharmacodynamics
Mode of Action
The documented mechanism, and why it doesn't match the marketing narrative.
🧬
Steroidal Saponin Precursors
The plant contains steroidal saponins that are structural precursors of testosterone — the basis for the traditional anabolic claim, though clinical trials largely fail to confirm a meaningful downstream hormonal effect in men with normal testosterone.
🩸
Nitric Oxide Synthase Pathway
In animal models, the extract activates a nitric oxide synthase-dependent pathway, relaxing corpus cavernosum smooth muscle and increasing intracavernosal pressure — a mechanism independent of androgen hormones, and the one best supported by the overall evidence.
Clinical Safety
Safety & Precautions
Generally well tolerated in human trials, with two genuinely separate concerns worth knowing.
Documented Toxicity
- Veterinary hepato- and nephrotoxicity: sheep grazing heavily on Tribulus develop locomotor and nervous system disorders alongside liver and kidney toxicity. [12]
- Contraindicated in children and pregnant women.
- Alkaloids and saponins in the plant are potentially toxic at high exposure.
Quality & Doping Concerns
- Species substitution: the herbal drug is frequently substituted with fruits of Pedalium murex, requiring specific botanical identification criteria to detect.[17]
- Anabolic steroid contamination: the benefits marketed to athletes have too often served to mask contamination of "natural" supplements with actual anabolic steroids, per anti-doping medical authorities.[15]
- Manage expectations: given the weak evidence for raising testosterone, be skeptical of products making strong anabolic claims.
Clinical Disclaimer: This monograph is for educational and professional reference only. It does not constitute medical advice, diagnosis, or treatment guidance. Always consult a qualified healthcare provider before initiating any phytotherapeutic regimen, particularly if you are pregnant, breastfeeding, an athlete subject to anti-doping testing, or a minor.
Common Questions
Frequently Asked Questions
Does Tribulus terrestris really increase testosterone?
Generally, no, despite heavy marketing to bodybuilders. A 2025 systematic review of clinical trials found that most studies in men with normal baseline testosterone showed no significant increase, and a controlled trial in resistance-trained men found no improvement in body composition or performance. The two studies that did show a testosterone increase involved men with hypogonadism (clinically low testosterone) specifically, and even then the increase was small.
What does Tribulus terrestris actually do, if not raise testosterone?
Its best-supported effect is on libido and erectile function, working through a nitric oxide-mediated pathway that relaxes the corpus cavernosum (erectile tissue) rather than by raising androgen hormones. Animal and some human studies support a real, if modest, effect on sexual function and erectile dysfunction independent of any change in testosterone levels.
Why is Tribulus terrestris also called the Maltese Cross?
Its fruit is a capsule made of five spiny, radiating carpels that visually resemble the five-pointed Maltese cross, giving rise to the French name "Croix de Malte" and similar names in other languages.
What is the recommended dose of Tribulus terrestris?
Clinical trials have most commonly used 400 to 750 mg per day for 1 to 3 months, though doses up to 1,500 mg per day (divided into multiple doses) have been used in some studies of sexual function. Always confirm dosing with a healthcare provider.
Is Tribulus terrestris safe?
Most human trials report it as well tolerated, but it is contraindicated in children and pregnant women, and its alkaloids and saponins are potentially toxic at high exposure. Documented veterinary cases show liver and kidney toxicity with neurological signs in sheep that grazed heavily on the plant. Separately, some "natural" Tribulus supplements marketed to athletes have been found contaminated with actual anabolic steroids.
Is the Tribulus terrestris I'm buying actually Tribulus terrestris?
This is a real concern. The dried fruit used as the herbal drug is frequently substituted with fruits from a different plant, Pedalium murex, and distinguishing the two requires specific botanical and microscopic criteria described in pharmacognosy literature. This is a genuine quality-control issue in the herbal supply chain for this plant.
Primary Literature
Bibliography
↑
1.
Gauthaman K, Ganesan AP. The hormonal effects of Tribulus terrestris and its role in the management of male erectile dysfunction — an evaluation using primates, rabbit and rat. Phytomedicine. 2008 Jan;15(1-2):44-54.
PubMed PMID:18068966 →
↑
2.
Ponnusamy S, Ravindran R, Zinjarde S, Bhargava S, Ravi Kumar A. Evaluation of traditional Indian antidiabetic medicinal plants for human pancreatic amylase inhibitory effect in vitro. Evid Based Complement Alternat Med. 2011;2011:515647.
PubMed PMID:20953430 →
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3.
Zhang JD, Cao YB, Xu Z, Sun HH, An MM, Yan L, Chen HS, Gao PH, Wang Y, Jia XM, Jiang YY. In vitro and in vivo antifungal activities of the eight steroid saponins from Tribulus terrestris L. with potent activity against fluconazole-resistant fungal pathogens. Biol Pharm Bull. 2005 Dec;28(12):2211-2215.
PubMed PMID:16327151 →
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4.
Hong CH, Hur SK, Oh OJ, Kim SS, Nam KA, Lee SK. Evaluation of natural products on inhibition of inducible cyclooxygenase (COX-2) and nitric oxide synthase (iNOS) in cultured mouse macrophage cells. J Ethnopharmacol. 2002 Nov;83(1-2):153-159.
PubMed PMID:12413723 →
↑
5.
Adaikan PG, Gauthaman K, Prasad RN, Ng SC. Proerectile pharmacological effects of Tribulus terrestris extract on the rabbit corpus cavernosum. Ann Acad Med Singapore. 2000 Jan;29(1):22-26.
PubMed PMID:10748960 →
↑
6.
Gauthaman K, Adaikan PG, Prasad RN. Aphrodisiac properties of Tribulus Terrestris extract (Protodioscin) in normal and castrated rats. Life Sci. 2002 Aug 9;71(12):1385-1396.
PubMed PMID:12127159 →
↑
7.
Milanov S, et al. Tribestan effect on concentration of some hormones in serum of healthy volunteers. Med-biol Inf. 1985;4:27-29.
↑
8.
Qureshi A, Naughton DP, Petroczi A. A systematic review on the herbal extract Tribulus terrestris and the roots of its putative aphrodisiac and performance enhancing effect. J Diet Suppl. 2014 Mar;11(1):64-79.
PubMed PMID:24559105 →
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9.
Iacono F, Prezioso D, Illiano E, Romeo G, Ruffo A, Amato B. Sexual asthenia: Tradamixina versus Tadalafil 5 mg daily. BMC Surg. 2012 Nov 15;12(Suppl 1):S23.
PubMed PMID:23173697 →
↑
10.
Antonio J, Uelmen J, Rodriguez R, Earnest C. The effects of Tribulus terrestris on body composition and exercise performance in resistance-trained males. Int J Sport Nutr Exerc Metab. 2000 Jun;10(2):208-215.
PubMed PMID:10861339 →
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11.
Neychev VK, Mitev VI. The aphrodisiac herb Tribulus terrestris does not influence the androgen production in young men. J Ethnopharmacol. 2005 Oct 3;101(1-3):319-323.
PubMed PMID:15994038 →
↑
12.
Glastonbury JR, Doughty FR, Whitaker SJ, Sergeant E. A syndrome of hepatogenous photosensitisation, resembling geeldikkop, in sheep grazing Tribulus terrestris. Aust Vet J. 1984 Oct;61(10):314-316.
PubMed PMID:6525116 →
↑
13.
Vilar Neto JdO, de Moraes WMAM, Pinto DV, da Silva CA, Caminha JdSR, Nunes Filho JCC, Reis CEG, Prestes J, Santos HO, De Francesco Daher E. Effects of Tribulus (Tribulus terrestris L.) Supplementation on Erectile Dysfunction and Testosterone Levels in Men — A Systematic Review of Clinical Trials. Nutrients. 2025 Apr 5;17(7):1275.
PubMed PMID:40219032 →
↑
14.
Vasilenko AT, et al. Evaluation of the efficacy and safety of Tribulus terrestris in male sexual dysfunction — a prospective, randomized, double-blind, placebo-controlled clinical trial. Maturitas. 2017 Jun;100:65-69.
PubMed PMID:28364864 →
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15.
Antenne Médicale de Prévention du Dopage (AMPD) Languedoc Roussillon. Lettre d'Actualités de Novembre 2007: Le Tribulus terrestris.
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16.
Adimoelja A. Phytochemicals and the breakthrough of traditional herbs in the management of sexual dysfunctions. Int J Androl. 2000;23(Suppl 2):82-84.
PubMed PMID:10849504 →
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17.
Kevalia J, Patel B. Identification of fruits of Tribulus terrestris Linn. and Pedalium murex Linn.: A pharmacognostical approach. Ayu. 2011 Oct;32(4):550-553.
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18.
Kam SC, Do JM, Choi JH, Jeon BT, Roh GS, Hyun JS. In vivo and in vitro animal investigation of the effect of a mixture of herbal extracts from Tribulus terrestris and Cornus officinalis on penile erection. J Sex Med. 2012 Oct;9(10):2544-2551.
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19.
Sellandi TM, Thakar AB, Baghel MS. Clinical study of Tribulus terrestris Linn. in Oligozoospermia: A double blind study. Ayu. 2012 Jul;33(3):356-364.
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20.
Singh S, Nair V, Gupta YK. Evaluation of the aphrodisiac activity of Tribulus terrestris Linn. in sexually sluggish male albino rats. J Pharmacol Pharmacother. 2012 Jan;3(1):43-47.
Additional Reference Literature
Do J, Choi S, Choi J, Hyun JS. Effects and Mechanism of Action of a Tribulus terrestris Extract on Penile Erection. Korean J Urol. 2013 Mar;54(3):183-188.