Looking to buy Tribulus Terrestris? Buy from Amazon.comWhy the buy link?
Tribulus Terrestris is a herb commonly sold as an aphrodisiac, sexual performance enhancer, and testosterone booster. Currently, it seems that it does have scientific grounds to claim it is an aphrodisiac and perhaps high doses could be seen as a sexual performance enhancer.
Science on Tribulus and testosterone is mixed and trending towards being ineffective. Currently three human studies have been conducted on the matter and found no fluctuations in testosterone with doses between 200-450mg Tribulus daily for up to 8 weeks. Higher doses in rats that correlate to 750mg in humans routinely find testosterone increases in castrated rats, and a single study exists to suggest that this testosterone boost at the same high dose can apply to normal rats.
Beyond those claims, Tribulus is claimed to be a heart healthy compound and a large dose (3g) has been demonstrated to reduce blood pressure over the course of 4 weeks, with noticeable improvement at one week, in persons with hypertension.
Looking to buy Tribulus Terrestris? Buy from Amazon.com
Follow this Page for updates
Trib, Zygophyllaceae, puncturevine, protodioscin
Given a 60% saponin extract, a dose of between 200-450mg a day is typically used for aphrodisiac effects and sexual enhancement. Doses up to 750mg of Bulgarian Tribulus is sometimes seen as an upper limit.
Looking to buy Tribulus Terrestris? Buy from Amazon.com or BodyBuilding.com | Life Extension Formula | VitaCost | Puritan's Pride
The Human Effect Matrix looks at human studies (excluding animal/petri-dish studies) to tell you what effect Tribulus Terrestris has in your body, and how strong these effects are.
|Grade||Level of Evidence|
|A||Robust research conducted with repeated double blind clinical trials|
|B||Multiple studies where at least two are double-blind and placebo controlled|
|C||Single double blind study or multiple cohort studies|
|D||Uncontrolled or observational studies only|
|Level of Evidence ||Effect||Change||Magnitude of Effect Size ||Scientific Consensus||Comments|
No alterations in testosterone levels are noted with recommended doses of tribulus supplementation
Insufficient evidence to support an increase of lean mass associated with tribulus relative to placebo during a training program.
No significant influences on fat mass are noted with tribulus terrestris
No significant alterations in power output associated with tribulus supplementation.
No influence on luteinizing hormone has been detected with supplemental tribulus
Exercise related fatigue and vigor is unaffected by tribulus supplementation in trained men
A decrease in blood pressure has been noted in hypertensive subjects; insufficient evidence to address efficacy in normotensive persons
A decrease in heart rate has been observed in hypertensive persons given tribulus supplementation
A decrease in cholesterol levels has been noted with tribulus supplementation
Looking to buy Tribulus Terrestris? Buy from Amazon.com or BodyBuilding.com | Life Extension Formula | VitaCost | Puritan's Pride
Tribulus Terrestris is an annual creeping herb widespread in China, eastern Asia, and extends into western Asia and southern Europe. The fruits have been used in Traditional Chinese Medicine for the treatment of eye trouble, edema, abdominal distention, high blood pressure, and cardiovascular diseases while in India its usage in Ayurveda was for the purpose of impotency, poor appetite, and cardiovascular diseases. It is also sometimes used to treat jaundice and urinary ailments. In Ayurvedic medicine, Tribulus Terrestris is referred to as Gokshura or Chhota Gokshura and currently is sometimes used in lower back pain, sciatica, inflammation of the pelvic and sacral region, dry cough, respiratory disorders. Another plant shares the name of Gokshura with the full name of Bada Gokshura, which is Pedalium murex.
The main components of Tribulus are:
The fruits of the Tribulus plant contain:
Both the fruits and the plant root itself appear to contain a variety of compounds that are roughly based on a steroid skeleton, steroidal saponins
Protodioscin, seen as the active muscle building compound (Tribulus' most heavily marketed claim), is highest in Turkey (Ankara), Bulgarian (Haskovo hirsut) and Macedonian (Bogdanzi glabr) respectively. These three species have more than double all other species.
The chemical make-up of the plant seems to vary by region of growth, with Vietnamese and Indian tribulus lacking both tribestin and prototribestin (the gitogeninic type)and having higher levels of tribulosin, at around 50-150 times more than the aforementioned species.
Much of the literature focuses on the extracts of Bulgarian, Chinese, and Indian origin; which proves problematic if the tribestin or protodioscin contents are the active components.
Although the region of Tribulus growth appears to influence the components, the major difference is in those grown in middle-eastern Europe and Western Asia having a higher protodioscin content and those grown in Eastern Asia and Oceania tending to have greater tribuloin content and no gitogenic saponins
Beyond the numerical differences of the above 6 compounds, Bulgarian Tribulus is the only extract to possess sulphated spirostanol and furostanol saponins and chinese tribulus seems to be the only compound with cisA/B ring junctures in their saponins.
There are other species in the Tribulus genus, which may have differing nutrient profiles and actions despite being in the same genus.
Tribulus Pentandrus seems to have a its flavonoid profile shifted more towards Kaempferol and various glycosides thereof while Terrestris has an approximately equal Quercetin content with a greater Isorhamnetin profile; Petandrus also appears to be a source of the flavonoid tricin (as Tricin-7-diglucoside) which is not present in Terrestris.
Tribulus Alatus appears to possess steroidal glycosides of the three classes similar to Terrestris (spirostane, furostane, cholestane) and this species appears to be implicated in increasing testosterone levels in rats after ingestion of either the aerial parts of the plant or the fruits, but with most benefit being observed with a chloroform fraction of the fruits.
Tribulus Terrestris has apparently been used to stimulate the appetite of persons.
One rat study investigating aphrodisia and using doses of 2.5mg/kg, 5mg/kg, and 10mg/kg Tribulus extract noted increases in bodyweight in all groups with 5mg/kg bodyweight responding best; this study did not record food intake specfically.
Despite claims to increase appetite, the evidence for it appears non-existent currently
At least one study has indicated that Tribulus may possess pain-reducing properties (in accordance with traditional usage in Iran and surrounding regions). In this study subjected mice to a chemical and thermal pain test (formalin and tail-flick, respectively) and although it was tested at various doses (50, 100, 200, 400, and 800) an injection of 100mg/kg Tribulus extract appeared to be most potent and tended to be less pain-relieving than 2.5mg/kg morphine yet more than 300mg/kg Aspirin; the mechanism of action is not mediated by opioid receptors.
When Tribulus extracts were tested to see if they possessed acetylcholinesterase inhibitory potential, it was concluded that they did not at concentrations of 1mg/mL and 10mcg/mL.
A combination supplement consisting of Tribulus, Emblica officinalis, and Tinospora cordifolia known as Ghana tablets was taken with a deliver vehicle (Ghee and Honey, for absorption) was given at 260mg/kg (according to a 2g human dose) and fed to rats acutely prior to testing. It was found that this dose of Ghana tablets was able to exert both anti-depressant and anxiolytic effects but was significantly outperformed on these parameters by the control drugs Diazepam (2mg/kg) and imipramine (5mg/kg), respectively.
Not much evidence, and even then it appears weak at best
A study in fertile boars with combination therapy of Tribulus, Eurycoma Longifolia Jack and Leuzea carthamoides noted that 11mg/kg oral administration (correlating to a 750mg oral dose for a 70kg human) increase mounting behaviour by 20% and increase seminal volume; higher doses (42mg/kg and 110mg/kg) were unaffective.
Various other animal models confirm aphrodisiac effects, including the lyophilized extract dried fruits at 50mg/kg and 100mg/kg in sexually sluggish male rats which noted dose-dependent increases in all parameters of sexuality and penile function increasing with prolonged administration. Intake of tribulus at lower doses of 2.5, 5, and 10mg/kg for a period of 8 weeks was associated with decreases in the latency of mounting, intromission, and ejaculation while improving mounting and intromission frequency; with 5mg/kg and 10mg/kg being of equal potency and in castrated rats Tribulus appears to be slightly less effective at 5mg/kg than were biweekly injections of testosterone cypionate at inducing aphrodisia, but both groups were lesser than an uncastrated control while another study comparing Tribulus Terrestris against Sildenafil Citrate (Viagra) in sexually normal rats at doses of 100mg/kg bodyweight and 0.71mg/kg, respectively, found that there were no significant differences between both groups, as both were more effective than control at inducing aphrodisia with similar efficacy.
Tribulus seeds have been demonstrated to inhibit pancreatic alpha-amylase activity, but with a relatively weak IC50 of 511mcg/mL which was significantly less than both isopropanol and acetone extracts of Curcuma Longa, the plant that gives Curcumin (0.16mcg/mL and 7.4mcg/mL; respectively). This has shown some efficacy in slowing the spike in blood glucose after a meal when dosed at 100mg/kg bodyweight.
May inhibit carbohydrate uptake slightly, does not appear to potent at doing so
One study using 2g/kg Tribulus Terrestris in a model of streptozotocin-induced diabetes noted that it was as effective as 10mg/kg glibenclamide in normalizing one serum liver enzyme (AST) and more effective in normalizing ALT and serum creatinine. This may have been secondary to prevention of damage to the liver, as assessed by histological examination.
Possibly can reduce some biomarkers, but a very high and unpractical dose of Tribulus was used
A complication with excessive insulin resistance and high blood glucose is the formation of cataracts on the eyes, and compounds that possess aldose reductase inhibtory potential can act as therapeutic against this pathology. Tribulus Terrestris extract has been tested, and its efficacy (IC50) in Rat Lens Aldose Reductase and Polyphenol Reductase assays was 0.348-0.444mg/mL and 0.439-0.705mg/mL, respectively, with the water extract tendign to be more effective than alcoholic and chloroform. These effects were weaker than other tested herbs such as Morinda cetrifolia (0.132mg/mL), Tinospora cordifolia (0.176mg/mL), and Holy Basil (0.280mg/mL) and was weaker than the control drug of Quercetin which had an IC50 value of 0.082mg/mL on Aldose Reductase.
May have efficacy in reducing aldose reductase activity, does not seem very potent at doing this relative to other herbs or reference drugs
Tribulus Terrestris, via the bioactive Tribulosin, appears to protect cardiomyocytes from cardiac reperfusion injury secondary to Protein Kinase C epsilon (PKCε) activation although it appeared to lack protective effects againts doxorubicin-induced cardiotoxicity.
In regards to the cardiac tissue itself, Tribulus appears to be somewhat protective on the tissue under periods of ischemia/reperfusion but may not benefit all parameters of cardiac health
A low dose of Tribulus fruits (10mg/kg lyophilized extract) to spontanously hypertensive rats (2K1C) appeared to reduce the elevated ACE activity and subsequently lower blood pressure. That being said, a study in otherwise healthy rats noted that prolonged intake of Tribulus at similarly relevant doses (2.5, 5, and 10mg/kg) had increases in blood pressure of 6%, 7%, and 11%, so at least in rats there are mixed reports. The only human study on Tribulus and blood pressure involves 75 patients with hypertension (140/90 to 179/109) using 3g of either the whole plant or a water extract (2 different groups, third being placebo) for four weeks and noted that systolic blood pressure was significantly reduced in one week by 4.3% and 4% (whole fruit and water extract; respectively) and by the fourth week these reductions reached 10.7% and 9.6% and a decrease in diastolic pressure was seen at the fourth week by 8.1% and 7.4%. A possible problem in this study is that the placebo had significantly lower blood pressure at baseline than did either experimental group, which may have exagerrated results; a reduction in heart rate and total cholesterol was also noted.
Tribulus has been implicated in possessing anti-platelet effects, although one study was conducted with a different species (Tribulus Pterocarpus) and this effect may apply to the Terrestris species that was found to inhibit adrenaline-induced platelet aggregation with an IC50 value of 970mcg/mL.
Appears to benefit blood flow and has been shown to with a high dose in humans (with hypertension), but mechanisms are not known. Possible anti-platelet effects
In rats fed Tribulus extract at 5mg/kg bodyweight under experimental cadmium toxicity, it was noted that Tribulus was able to reverse oxidative and organ changes induced by cadmium to a degree. When compared to 75mg/kg Vitamin E (alpha-tocopherol) Tribulus appeared to be similar in potency for normalizing antioxidant enzymes and lipid peroxidation in the liver, although Vitamin E trended to be more protective. Protective effects have also been noted againts tacrine-induced hepatotoxicity with Tribulus fruits and mercury toxicity and currently the bioactives that may cause this are the Tribulusamides (A and B).
Anti-inflammatory effects have been noted with the aqueous extract of Tribulus in vitro, where suppression of HepG2 tumor cell growth was noted (and no effect on normal cell growth) and thought to be secondary to increasing IκBα content and reducing nF-kB content, the former of which appears to be through inhibiting the IκBα kinase enzyme (although it did not influence binding of the IKK-β subunit, usually implicated with nF-kB).
Tribulus has shown protective effects in Kidneys in an experimental model of cadium toxicity, where 5mg/kg bodyweight Tribulus was not significantly different than 75mg/kg Vitamin E. Protective effects have also been noted with mercury toxicity in kidney tissue.
Tribulus Terrestris appears to have anti-inflammatory properties in stimulated macrophages, as an induction of COX-2 and inhibition of iNOS (anti-inflammatory events) have been noted in vitro with greater than 80% inhibition at 10mcg/mL.
Two studies have been conducted with Tribulus Terrestris, and neither have shown promise. The former study in resistance trained males notes that 8 weeks of supplementation failed to improve bench and leg press performance more than placebo and was not accompanied by any changes in lean mass or fat mass and a study conducted in elite rugby players using 450mg Tribulus for 5 weeks failed to improve strength or bodycomposition.
No promising evidence that it does anything
A tribulus terrestris extract (Bulgarian, thus higher protodioscin) seems to be able to increase androgen receptor (AR) immunoreactivity in the rat hypothalamus (specifically, the PVN) when dosed at 5mg/kg bodyweight for 8 weeks, increasing from 162.67+/-14.73 ARs to 383.17+/-15.73 ARs (58%) suggesting it may alter androgen signalling. There was also a significant increas in neurons expressing NADPH-d by 67%, suggesting that Tribulus can increase Nitric Oxide Synthase (NOS) and subsequent NO production as NADPH-d immunostaining can be a biomarker for NOS activity.
When testing for androgenic effects of Tribulus independent of serum testosterone levels, a rat study measuring prostate weight of rats subject to 11, 42, and 110mg/kg Tribulus extract (11.42% Protodioscin) with the lowest dose correlating to 750mg Tribulus extract in a 70kg human noted that, over 28 days of feeding, that aside from serum testoterone being unaffected prostatic weight was unaffected at all doses suggesting no intrinsic androgenic activity.
A plausible mechanism for anabolic effects of Tribulus is increased androgen receptor expression, similar to L-Carnitine (although neither study measured lean mass accrual). However, direct androgenic effects independent of circulating testosterone (what would be seen with a receptor agonist) have been shown to not occur
When looking at interventions, currently those that show an increase in circulating testosterone including a non-human primate injection of isolated protodioscin (7.5mg/kg) resulting in a 52% increase acutely which returned to baseline 90-180min after injection. This same study noted that 8 weeks administration of 5-10mg/kg in rabbits and rats led to increases in dihydrotestosterone (DHT) in rabbits (testosterone increases statistically insignificant) and in the castrated rats testosterone increased by 25% and another study exclusively using sexually sluggish rats (those that were previously shown to copulate less with receptive females) noted an increase in testosterone from 2.4+/-0.03ng/mL to 3.12+/-0.06 and 3.72+/-0.06ng/m (30% and 55% increase) with 50mg/kg and 100mg/kg fruit extract, respectively. One other study using otherwise healthy rats has noted, offhand, an increase in testosterone with both the control drug (Viagra at 0.71mg/kg) and Tribulus fruits at 100mg/kg but does not disclose total increases.
Only one other study notes increases in testosterone, and used 50mg/kg of the species Tribulus Alatus with similar results as the aforementioned two studies using 50-100mg/kg Tribulus fruits. This study used otherwise healthy and non-castrated rats.
Some studies have shown increases in testosterone, but currently the only rat studies to note increases with oral ingestion are those done in sexually deficient mice. One study exists showing a testosterone boost in healthy mice, but it used the Species of Tribulus Alatus; it is not known whether this is exclusive to this species, as there just have not been studies using that dose (50mg/kg) of dried fruits of Terrestris in healthy rats
Tribulus of Bulgarian origin has been shown to have no influence on total testosterone or luteinizing hormone levels when supplemented to healthy men in 200mg a day with a 60% saponin content. It does not seem to influence testosterone levels in females at 450mg (low powered case studies) and when 450mg Tribulus is adminsitered to weight trained men and rugby players for up to 5 weeks fails to note significant increases in testosterone.
It should be noted that based on body surface area conversions an oral dose of 450mg Tribulus equates to 30.94mg/kg in rat studies if we assume a 200lb human. Previous studies with dehydrate fruit extracts of Tribulus note increases in testosterone with 50-100mg/kg bodyweight in rats, which correlates to a 200lb human ingesting 727mg-1.45g Tribulus fruits.
Actual human evidence for Tribulus Terrestris increasing testosterone after supplementation is lacklustre, with all trials using Tribulus in isolation coming back negative when otherwise healthy and sexually sufficient humans are used. It is possible that higher doses of Tribulus could influence testosterone, but the only studies to work from are animal models using Tribulus fruits rather than aerial parts
A rat study using female rats and assessing intrinsic estrogenic potential of Tribulus Terrestris found no significant effect of extracts of 11, 42, and 110mg/kg bodyweight where the lowest dose correlates to a 750mg oral intake for a 70kg human.
In rabbits, the active compound of Tribulus Terrestris (Protodioscin) was shown to be ineffective as a pro-erectile agent on its own, but potentiated the pro-erectile effects of other known agents. This may work in conjunction with other components of the herb, as another study in rabbits fed Tribulus for a month noted that intracavernous pressure of the penis was greater after herbal administration when compared against baseline, and appeared to be associated with an increase in cAMP.
When administered to rats, oral intake of 2.5, 5, and 10mg/kg bodyweight Tribulus Terrestris for a period of 8 weeks is able to increase the intracavernous pressure of the penis by 17%, 43%, and 26% at the respective doses; this was accompanied by an increase in general blood pressure by 6%, 7%, and 11% respectively.
Possibly a pro-erectile agent, with mechanisms currently unknown. May increase the blood pressure of the penis secondary to, at least in part, systemic increases in blood pressure
A study using an extract of Tribulus at 5mg/kg bodyweight in rats (around 450mg oral dose for humans) and conducting in vitro tests noted that Tribulus (at 50mcg/mL) had a lesser mineral binding affinity and anti-oxidative capacity than Vitamin E (alpha-tocoperhol) and oral pretreatment of Tribulus was able to attenuate adverse changes to the testicles in a model of cadmium toxicity and was less effective than 75mg/kg alpha-tocopherol.
Increased semen volume has been noted with 11mg/kg Tribulus in boars, correlating to a 750mg/kg oral dose; this was not observed with 42mg/kg and 110mg/kg. Increase sperm count has been noted in rats with 50mg/kg and 100mg/kg lyophilized Tribulus fruit extract over 28 days (+25.8% and +32.2%, respectively). These observations are matched with one of increased testicular weight that was not associated with any adverse histological pathology.
Benign Prostatic Hyperplasia (BPN) is a condition that is not harmful per se but may be indicative of disease pathology leading to more serious diseases such as Prostate Cancer and may be associated with impairment of a male's quality of life or interfering with urinary flow rates. The current most promising over-the-counter remedies for BPN are Stinging Nettle with some efficacy seen with Saw Palmetto.
Tribulus has been investigated for its benefits on BPN, although this study used a combination supplement of Tribulus Terrestris and Murraya koenigii. Although only 12 weeks in length, the combination supplement was able to reduce IPSS symptoms from a score of 17 down to 9, which was not significantly different than the efficacy of 400mcg tamsulosin reducing IPSS symptoms from 14 to 8; the herbal combination reduced prostatic volume from 33.5mL to 31.6mL (5.6% reduction) and was statistically significant while the 3.4% reduction seen with tamsulosin did not reach significance. This study was criticized for its usage of generic tamsulosin (and thus no control for active amounts of tamsulosin) paired with a lack of placebo group.
Another possible confound to the above research is that IPPS symptoms include urinary flow, as Benign Prostatic Hyperplasia may sometimes reduce flow rate. Tribulus itself appears to possess diuretic properties, although this study used a large dose of Tribulus where 5g/kg in Guinea pigs was as effective as furosemide.
Possibly beneficial for benign prostatic hyperplasia, but evidence is limited and no mechanisms are known
It was mentioned in this review reported a study where 98% (49/50) women reported improvement in Menopausal symptoms after taking a Tribulus product, but mentioned that the study was questionable due to possible conflict of interest and lack of mention of measurements. The only other study conducted on Tribulus's effects on female sexuality has been conducted in rats, where it was determined that Tribulus with a 16.42% protodioscin content failed to exert estrogenic activity. All current aphrodisiac studies are conducted in male mice.
Lack of information all around
Tribulus terrestris seems to also be able to stimulate Melanocyte-stimulating hormone when orally administered at a large dose (1g/kg for humans), which increased the rate of MSH detection in hair follicles from 18.75% in control to 75% in the Tribulus group. A later in vitro study demonstrated that a result of Melanocyte-Stimulating Hormone, the actual proliferation of melanocytes, appears to be concentration dependent with 0.5mg/mL actually inhibiting proliferation and 1.5mg/mL inducing proliferation. These effects on melanocyte differentiation were also correlated with tyrosinase activity, suggesting that high doses of Tribulus may have the ability to induce hair pigmentation.
May have the ability to induce coloration of hair follicles at high concentrations, but results are too preliminary to implicate any practical guides
A 28-day oral toxicology test of 500mg/kg lyophilized dry fruit extract in rats (80mg/kg human dose) failed to establish any toxic signs and another LD50 study found that the LD50 of a basic lyophilized extract of Tribulus (aerial parts and root) as assessed by intraperitoneal injections was 813mg/kg and the 95% condfidence interval calculated to be 739-894mg/kg, suggesting that a lethal dose of Tribulus injections in humans would be (based on body surface area conversions) 118-143mg/kg. Due to unknown bioavailability, it cannot be estalished what a toxic oral dose would be.
Doses typically used for supplementation do not appear to be lethal or harmful
One case study noted gynecomastia and reduced testosterone associated with Tribulus Terrestris supplementation, amidst other factors. This study involved a 21-year old man with a history of breast swelling whom used cigarettes (2 daily) and drank Alcohol (10 units weekly) who reported development of a benign nodule in the left breast that coincided with consumption of a Tribulus product (unnamed). Causation could not be placed on the product.
There has been a reported case study of nephrotoxicity associated with Tribulus Water (drinking bottle, acquired from a grocer). This study reported a young healthy man who took Tribulus water for two days prior to the event, with only a medical history of two kidney stones in the past; the symptoms involved seizures and both hepatic and renal complications, the former of which resolves spontaneously within a week. A reply to this articel suggested that implications for causation were premature as symptoms seen in the patient were also similar to microbial contamination (which may have occured in a case study) and the two examples the aforementioned research drew on to illustrate Tribulus Toxicity (Geeldikkop and Staggers) are exclusive to ruminants and not humans.
Standard assortment of case studies, with little evidence to outright blame Tribulus for the effects caused
(Common misspellings for Tribulus Terrestris include territis, terrestis, terestris, tibulus, tribuls)
(Common phrases used by users for this page include tribulus testosterone booster studies, tribulus terrestris scientific study, tribu power review, may i take two table tribulus terrestris for sex, how to use tribilus, ayurvedic testosterone booster)