Tribulus terrestris: Uses, Evidence, Safety and Side Effects

By the NutriFactGuide Editorial Desk

Quick summary: Tribulus terrestris is a thorny, ground-hugging plant used for centuries in Ayurvedic, Chinese and European folk medicine, and today it is sold mainly as a sexual-health and sports supplement. Laboratory and animal studies are interesting, but human trials do not support the popular claim that it raises testosterone or builds muscle. Evidence for sexual desire and erectile function is promising yet limited. Most people tolerate it in the short term, though rare serious adverse events have been reported.

Introduction

Walk into almost any supplement shop and you will find a bottle of Tribulus terrestris promising higher testosterone, better stamina and improved libido. The marketing is bold, but the science is more modest and more nuanced. This guide separates what is established from what is traditional belief or preliminary research. It covers the plant itself, its chemistry, how it has been used, what human studies actually show, and what is known about side effects and safety.

This article is educational and is not medical advice. Speak with a qualified healthcare professional before using any herbal supplement, especially if you have a medical condition or take prescription medicines.

What Is Tribulus Terrestris?

Tribulus terrestris L. belongs to the Zygophyllaceae (caltrop) family. It is a low-growing annual that spreads along the ground in warm, dry regions of southern Europe, Asia, Africa and Australia, and it has become a weed in many parts of the world. It produces small yellow flowers and a hard, spiked fruit that can pierce shoes and bicycle tyres, which explains common names such as puncture vine, caltrop and goat's head.

The plant goes by different names in traditional systems. In Ayurveda it is called Gokshura, in Traditional Chinese Medicine Bai Ji Li, and in Bulgaria, where much of the commercial research began, it has long been cultivated for supplement production. Fruits, leaves and roots are all used, and the choice of part affects the chemical profile of the final product.

Key Chemical Compounds

The plant contains a wide range of compounds, including flavonoids, alkaloids, lignan amides, phenolic compounds and, most notably, steroidal saponins. A comprehensive review of the plant's phytochemistry describes the saponins as the group most often linked to its biological effects (Ștefănescu et al., 2020; Kostova and Dinchev, 2005).

Protodioscin is the saponin most frequently highlighted by manufacturers, and many products are standardized to a percentage of saponins or protodioscin. The problem is that the composition of the plant is not constant. Research comparing plants from different geographical regions found marked differences in saponin types and amounts; for example, material from Bulgaria and neighbouring regions differed from that grown in parts of Asia (Dinchev et al., 2008). Growing conditions, harvest time, the plant part and the extraction method all change the final product. As a result, two bottles labelled Tribulus can contain very different things.

Traditional Uses

Traditional use is not clinical proof, but it explains why the plant attracted scientific attention. In Ayurvedic medicine Gokshura has been used for urinary complaints, kidney stones, and as a general tonic for male reproductive health. In Chinese medicine the fruit has been used for conditions described as liver-related, including headaches, red eyes and dizziness, as well as for itching skin conditions. In parts of Europe and the Middle East it was used as a diuretic and as a folk aphrodisiac (Chhatre et al., 2014).

The modern reputation as a testosterone booster is much newer. It grew in the late twentieth century, partly after reports that Eastern European athletes used Tribulus preparations, which led to its marketing in the sports nutrition sector. A systematic review of the literature traced how the aphrodisiac and performance-enhancing claims developed and noted that the commercial story ran well ahead of the clinical data (Qureshi et al., 2014).

Evidence for the Most Common Uses

1. Testosterone and Athletic Performance

This is the most popular reason people buy Tribulus, and it is where the evidence is weakest.

The theory is that protodioscin might raise luteinizing hormone, which in turn would stimulate testosterone production. Some animal studies reported hormonal changes. In rats, primates and rabbits, extracts increased certain hormone levels and affected the tissues involved in erection (Gauthaman and Ganesan, 2008; Gauthaman et al., 2002). However, animal results often do not translate to humans.

Human studies are much less encouraging:

• In a trial of resistance-trained young men, eight weeks of Tribulus supplementation did not improve body composition or exercise performance compared with placebo (Antonio et al., 2000).

• A study of elite rugby league players over five weeks of pre-season training found no improvement in strength or body composition from Tribulus (Rogerson et al., 2007).

• Research in healthy young men found that the herb did not raise androgen production (Neychev and Mitev, 2005).

• A doping-control study found that short-term Tribulus intake did not change the urinary steroid markers used to detect testosterone abuse (Saudan et al., 2008).

Taken together, these studies suggest that Tribulus does not meaningfully increase testosterone in healthy men and should not be relied on for muscle gain. The same conclusion was reached in the systematic review by Qureshi and colleagues (2014).

2. Male Sexual Function and Erectile Dysfunction

In laboratory studies, Tribulus extracts relaxed the smooth muscle of rabbit penile tissue and increased intracavernous pressure in animals, effects thought to involve nitric oxide pathways (Adaikan et al., 2000; Gauthaman and Ganesan, 2008).

Human evidence is limited but somewhat more positive than for muscle building. A randomized, double-blind, placebo-controlled trial in men with erectile dysfunction reported improvement in erectile function scores in the Tribulus group compared with placebo, with a good tolerability profile in the study (Kamenov et al., 2017). The result is encouraging, but a single trial of moderate size and duration is not enough to make firm recommendations. Larger studies from independent groups are needed, and men with persistent erectile problems should be evaluated by a doctor because the cause may be cardiovascular, hormonal or metabolic.

3. Female Sexual Desire

A randomized, double-blind, placebo-controlled study in women with hypoactive sexual desire reported improvements in desire and related sexual function measures after Tribulus treatment compared with placebo (Akhtari et al., 2014). As with the male trials, the sample was small and the follow-up short, so this should be viewed as preliminary.

4. Male Fertility

Small clinical studies have examined whether Tribulus can improve semen parameters. A double-blind study in men with low sperm count (oligozoospermia) reported improvements in some semen measures (Sellandi et al., 2012). Another study of infertile men reported effects on semen quality (Salgado et al., 2017). These findings are interesting, but the studies are small, vary in design and used different preparations. Fertility has many causes, so men trying to conceive should seek a proper medical assessment rather than self-treating.

5. Blood Sugar and Cholesterol

Some animal experiments and a small human study suggest that Tribulus may lower blood glucose and influence lipids. In a trial involving women with type 2 diabetes, the extract was associated with changes in serum glucose and lipid measures (Samani et al., 2016). Because the evidence is limited, Tribulus should not replace diabetes medication, and anyone using glucose-lowering drugs needs medical guidance (see the interactions section below).

6. Other Proposed Uses

Preclinical research has examined diuretic, antioxidant, anti-inflammatory, cardioprotective and anti-urolithiasis (kidney stone) effects. Most of this work is done in cells or animals, and human proof is lacking (Chhatre et al., 2014; Ștefănescu et al., 2020). These uses should be regarded as hypotheses for future research, not established benefits.

Dosage: What Is Known

There is no officially established dose for Tribulus terrestris. Clinical studies have used different plant parts, extract types and saponin concentrations, ranging from a few hundred milligrams to over a gram of extract per day, usually for periods of weeks to a few months. Because products differ so much, a dose from one study cannot be applied safely to another product. The safest approach is to follow the manufacturer's label for a product that has been independently tested, and to discuss use with a healthcare professional. Long-term safety data are lacking, so extended use is not well characterized.

Side Effects and Safety

Common and Mild Effects

In the clinical trials listed above, Tribulus was generally well tolerated over short periods. The most commonly reported complaints in the literature are gastrointestinal, such as stomach upset, nausea, cramping or diarrhea. Some users describe restlessness, irritability or sleep disturbance, though these reports are largely anecdotal and not well quantified. Taking supplements with food may reduce stomach discomfort.

Rare but Serious Reports

Case reports in the medical literature show that serious reactions can occur, although they appear to be uncommon:

• Kidney injury: A published case described severe nephrotoxicity in a previously healthy young man who used a Tribulus terrestris product (Talasaz et al., 2010).

• Breast tissue enlargement: A case report linked a plant product containing Tribulus terrestris with gynaecomastia in a man (Jameel et al., 2004).

Case reports cannot prove cause and effect, and the products involved may have contained other ingredients. Still, they are a reminder that natural does not automatically mean safe. A review of toxicological data has also highlighted the need for more safety research and better quality control (Ștefănescu et al., 2020). Livestock poisoning, particularly in sheep that graze on large amounts of the plant, is well known in veterinary medicine, which further illustrates that the plant is biologically active.

Possible Interactions

The following are theoretical or based on limited data, but worth discussing with a clinician:

• Diabetes medicines: Tribulus might lower blood glucose, so combining it with insulin or oral agents could increase the risk of low blood sugar.

• Blood pressure medicines: Some animal studies suggest blood pressure-lowering and diuretic effects, which could add to prescription treatments.

• Lithium: Because of possible diuretic action, the herb may in theory affect how the body handles lithium.

• Hormone-sensitive conditions: People with hormone-sensitive cancers or conditions should avoid use unless supervised by their specialist, since the effect of the herb on hormones is not fully understood.

• Surgery: Because of possible effects on glucose and blood pressure, it is commonly advised to stop herbal supplements ahead of planned surgery, following the instructions of the surgical team.

Who Should Avoid It

Because safety data are insufficient, Tribulus should be avoided during pregnancy and breastfeeding, and by children and adolescents. People with kidney or liver disease, diabetes, low blood pressure or hormone-related conditions should only use it with medical supervision.

Product Quality and Sports Testing

Supplements are regulated less strictly than medicines in many countries, and Tribulus products show large variability. An analysis of Tribulus-containing sports supplements found considerable differences in labelling and content among products (Pokrywka et al., 2014), and the natural variability in saponin content makes standardization difficult (Dinchev et al., 2008).

For athletes, there is an extra concern. Tribulus itself has not been shown to alter the urinary steroid profile in short-term testing (Saudan et al., 2008), but supplements sold for sport have a history of being mislabelled or contaminated with undeclared substances. Athletes who are subject to anti-doping rules should consult their governing body and choose products certified by an independent third-party testing program.

When choosing a product, look for:

• A clear botanical name (Tribulus terrestris) and the plant part used

• A stated extract ratio or saponin percentage

• Independent third-party testing for purity and contaminants

• No proprietary blends that hide ingredient amounts

• A realistic label, with no claims of curing disease or guaranteed muscle gain

Frequently Asked Questions

Does Tribulus increase testosterone? In healthy men, controlled human studies have not shown a meaningful rise in testosterone (Neychev and Mitev, 2005; Antonio et al., 2000; Rogerson et al., 2007). Some small studies in men with sexual dysfunction report other benefits, but this is not the same as boosting hormone levels.

Is Tribulus safe to take every day? Short-term use appears to be tolerated by most healthy adults in trials, but long-term safety is not established and rare serious cases have been reported. Daily use over long periods should be discussed with a healthcare professional.

Can women use Tribulus? One clinical study examined women with low desire and reported improvement (Akhtari et al., 2014), but the evidence is limited, and it should not be used during pregnancy or breastfeeding.

Is Tribulus legal? It is sold as a dietary supplement in many countries, but regulations differ. Check the rules in your country.

The Bottom Line

Tribulus terrestris is a fascinating plant with a long history in traditional medicine and a plausible chemistry. However, the claims made by many supplement sellers go beyond the evidence. Human studies do not support its use as a testosterone booster or muscle builder. There is early, encouraging evidence that it may support sexual desire and erectile function, and small studies hint at benefits for semen quality and blood glucose, but these results need confirmation in larger, independent, long-term trials. Side effects are usually mild, yet rare cases of kidney problems and hormonal effects have been reported, and product quality varies widely.

If you are considering Tribulus, treat it as an experimental supplement rather than a proven therapy, choose a tested product, and involve a healthcare professional, particularly if you have a medical condition or take medication.

Medical Disclaimer

The information in this article is for educational purposes only and does not replace professional medical advice, diagnosis or treatment. Always consult a qualified healthcare provider before starting a new supplement.

References

1. 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;29(1):22-26.

2. Akhtari E, Raisi F, Keshavarz M, et al. Tribulus terrestris for treatment of sexual dysfunction in women: randomized double-blind placebo-controlled study. Daru. 2014;22(1):40.

3. 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;10(2):208-215.

4. Chhatre S, Nesari T, Somani G, Kanchan D, Sathaye S. Phytopharmacological overview of Tribulus terrestris. Pharmacogn Rev. 2014;8(15):45-51.

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6. Gauthaman K, Adaikan PG, Prasad RN. Aphrodisiac properties of Tribulus terrestris extract (protodioscin) in normal and castrated rats. Life Sci. 2002;71(12):1385-1396.

7. 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;15(1-2):44-54.

8. Jameel JKA, Kneeshaw PJ, Rao VSR, Drew PJ. Gynaecomastia and the plant product Tribulus terrestris. Breast. 2004;13(5):428-430.

9. Kamenov Z, Fileva S, Kalinov K, Jannini EA. Evaluation of the efficacy and safety of Tribulus terrestris in male sexual dysfunction: a prospective, randomized, double blind, placebo-controlled clinical trial. Maturitas. 2017;99:20-26.

10. Kostova I, Dinchev D. Saponins in Tribulus terrestris: chemistry and bioactivity. Phytochem Rev. 2005;4:111-137.

11. Neychev VK, Mitev VI. The aphrodisiac herb Tribulus terrestris does not influence the androgen production in young men. J Ethnopharmacol. 2005;101(1-3):319-323.

12. Pokrywka A, Obmiński Z, Malczewska-Lenczowska J, Fijałek Z, Turek-Lepa E, Grucza R. Insights into supplements with Tribulus terrestris used by athletes. J Hum Kinet. 2014;41:99-105.

13. 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;11(1):64-79.

14. Rogerson S, Riches CJ, Jennings C, Weatherby RP, Meir RA, Marshall-Gradisnik SM. The effect of five weeks of Tribulus terrestris supplementation on muscle strength and body composition during preseason training in elite rugby league players. J Strength Cond Res. 2007;21(2):348-353.

15. Salgado RM, Marques-Silva MH, Gonçalves E, Mathias AC, Aguiar JG, Wolff P. Effect of oral administration of Tribulus terrestris extract on semen quality and body fat index of infertile men. Andrologia. 2017;49(5):e12655.

16. Samani NB, Jokar A, Soveid M, Heydari M, Mosavat SH. Efficacy of Tribulus terrestris extract on the serum glucose and lipids of women with diabetes mellitus. Iran J Med Sci. 2016;41(3 Suppl):S5.

17. Saudan C, Baume N, Emery C, Strahm E, Saugy M. Short term impact of Tribulus terrestris intake on doping control analysis of endogenous steroids. Forensic Sci Int. 2008;178(1):e7-e10.

18. Sellandi TM, Thakar AB, Baghel MS. Clinical study of Tribulus terrestris Linn. in oligozoospermia: a double blind study. Ayu. 2012;33(3):356-364.

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20. Talasaz AH, Abbasi MR, Abkhiz S, Dashti-Khavidaki S. Tribulus terrestris-induced severe nephrotoxicity in a young healthy male. Nephrol Dial Transplant. 2010;25(11):3792-3793.