Herb & supplement monograph

Tribulus Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Tribulus interacts with medications. The heart of this page is the interaction list — every drug Tribulus is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Tribulus is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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On this page

Tribulus Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Tribulus drug interaction appears low for most people, though those taking a few closely-monitored medicines should be more careful. None of the listed interactions are rated major, and most rest on limited or theoretical evidence rather than well-controlled human studies.

Interactions deserving the most attention

The best-supported concern involves diabetes medications, since clinical research shows Tribulus can lower blood sugar in adults with type 2 diabetes, which could add to the effect of their medication and raise the chance of low blood sugar. Lithium also deserves attention because Tribulus may act as a mild diuretic, which could reduce how the body clears lithium and raise its levels, and lithium has a narrow safety margin. Tribulus has also lowered blood pressure in some studies, so people on blood pressure medications should watch for added effects like dizziness.

What the rest of the list means

The long list of interacting medications largely reflects a few broad categories, such as the many different diabetes and blood pressure drugs, rather than hundreds of separate proven problems. Much of the concern comes from animal research or predicted effects, and these have not been confirmed as clinically meaningful in people for most combinations.

Check your medications against Tribulus

Based on HelloPharmacist’s Tribulus interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Tribulus

259 medications have a known interaction with Tribulus, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Tribulus using our pharmacist-reviewed interaction data.

AI summaries are generated from our Tribulus interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Tribulus combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Tribulus affects

Every type of medication (drug category) Tribulus is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 3 drug categories Tribulus interacts with

Antidiabetes DrugsAntihypertensive DrugsLithium

Antidiabetes Drugs

Taking tribulus with antidiabetes drugs might increase the risk of hypoglycemia.
Clinical research shows that Tribulus can lower blood glucose levels in adults with type 2 diabetes who are taking antidiabetes medications.

Likelihood Possible Evidence D

Antihypertensive Drugs

Theoretically, taking tribulus with antihypertensive drugs might increase the risk of hypotension.
Animal research shows that tribulus can lower blood pressure by inhibiting angiotensin-converting enzyme (ACE). Tribulus has also demonstrated hypotensive effects in pre-hypertensive adults.

Likelihood Possible Evidence D

Lithium

Theoretically, tribulus might increase the levels and clinical effects of lithium.
Tribulus is thought to have diuretic properties. Due to these potential diuretic effects, tribulus might reduce excretion and increase levels of lithium. The dose of lithium might need to be decreased.

Likelihood Probable Evidence D

Monograph

Tribulus: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

Tribulus is a plant supplement most often marketed to boost libido, testosterone, and athletic performance, but the human evidence behind these claims is weak and inconsistent. It is generally well tolerated by healthy adults in the short term, but it should be avoided during pregnancy and breastfeeding and discussed with your pharmacist or doctor before use.

Scientific name: Tribulus terrestris
Family: Zygophyllaceae
Part used: Fruit, leaf, and root
Common forms: Capsules, tablets, powders, tinctures, and standardized extracts

People commonly use it for

Low libido and sexual function
Athletic performance and muscle building
Testosterone support
Male and female fertility
General 'vitality' or wellness

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallUse caution

Often well tolerated short-term in healthy adults, but quality and long-term safety data are limited.

PregnancyPossibly Unsafe

When used orally. Animal research suggests that tribulus might adversely affect fetal development; avoid using.

Read the full pregnancy detail

BreastfeedingInsufficient reliable information

Insufficient reliable information available; avoid using.

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Jump to a section

Overview

Tribulus (Tribulus terrestris) is a low-growing plant that produces small yellow flowers and spiky, hard fruit. Because of its sharp burrs it is sometimes called caltrop, puncture vine, or bindii. It grows in many warm and tropical parts of the world, including Africa, Asia, southern Europe, and Australia.

The plant has a long history in traditional medicine systems, including Ayurveda and traditional Chinese medicine. Today the fruit, leaf, and root are dried and made into capsules, tablets, powders, and liquid extracts. It is one of the most widely sold ingredients in supplements marketed for sexual health and sports performance.

How it works

Tribulus contains a mix of plant compounds, including steroidal saponins such as protodioscin, as well as flavonoids and alkaloids. Protodioscin is the compound most often credited with the plant's possible effects.

Researchers have proposed that these saponins may influence hormones such as testosterone and DHEA, or that they may affect blood flow and nitric oxide pathways that play a role in sexual function. However, much of this is based on laboratory and animal studies, and the findings have not been clearly confirmed in well-designed human trials.

Effectiveness

Does Tribulus work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 20 uses evaluated

1 Possibly effective 1 Leans ineffective 18 Insufficient evidence

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

Possibly Effective Sexual dysfunction