Tribulus is an herb that has been used in various systems of traditional medicine for enhancing libido, fertility, and vitality. Although many take tribulus seeking a natural “testosterone boost,” this herb won’t actually alter testosterone levels in healthy men. Read on to discover how it does work, along with a breakdown of its science-based health benefits and side effects.
What is Tribulus Terrestris?
Tribulus (Tribulus terrestris) is a plant that grows in the Mediterranean and in subtropical and desert regions around the world, including India, Vietnam, China, Spain, Mexico, and Bulgaria. This common weed is particularly well-adapted to warm, dry regions. It got its nicknames “puncture vine” and “devil’s thorn” from the spikes that cover its fruits [1, 2].
This plant has a long history of use in ancient medicine systems. As part of Indian and Chinese traditional medicine, the roots and the fruits of tribulus were considered remedies for numerous ailments and used as general health tonics. Its historical uses include boosting libido and fertility, flushing fluid buildup (edema), reducing kidney stones, and fighting urinary tract infections .
Today, tribulus is commonly marketed and supplemented for increasing testosterone, libido and strength. Tribulus supplements are popular performance enhancers among bodybuilders. Others take tribulus for its alleged heart-protective effects or to remedy sexual issues.
As the popularity of tribulus increased, so did the misconceptions and false information surrounding its use. For one, taking tribulus to boost testosterone and athletic performance probably won’t work. Tribulus may help with sexual dysfunction and low libido, but its active compounds seem to have a testosterone-independent mechanism of action .
Additionally, tribulus supplements have not been approved by the FDA for medical use. Supplements generally lack solid clinical research. Regulations set manufacturing standards for them but don’t guarantee that they’re safe or effective. Speak with your doctor before supplementing.
Scientists believe that saponins and flavonoids in tribulus are responsible for the effects of this plant. Of these, the steroidal saponin protodioscin is the most important one. Extracts of tribulus are usually standardized to contain a certain percentage of saponins in the form of protodioscin [5, 1, 6].
- Alkaloids (harmane, nonharmane, tribulusterine)
- Phenolic amides (terrestrosides A and B)
- Phytosterols (β-sitosterol, stigmasterol)
- Organic acids (cinnamic acid, vanillic acid, Tribulus acid)
- Amino acids (alanine and threonine)
The saponin profile varies depending on where the plant is grown. For example, studies suggest that varieties in southeast Europe (e.g. Bulgaria and Greece) have over 30 times the amount of protodioscin than varieties in Western Asia [18+].
Mechanism of Action
Researchers have proposed the following mechanism of action of the active compounds found in tribulus.
- The steroidal saponin protodioscin is thought to be responsible for the libido-enhancing effects of this plant. It acts as an aphrodisiac, increasing sexual activity and blood flow to the sexual organs (by boosting nitric oxide) [19, 20].
- Other saponins (terrestrosides A and B and terrestrosin D) are a target of cancer research in cell culture .
- Other active compounds (such as tribulosin and tribulusamides) are being investigated for affecting inflammation and survival of healthy cells exposed to stress [11, 12, 16, 13, 21+].
The concentration of these active compounds in different formulations varies.
Purported Benefits of Tribulus Terrestris
The benefits in this section will all refer to the most well-studied species, Tribulus Terrestris, as tribulus.
Possibly Effective for:
Enhancing Libido and Sexual Function
Hypoactive sexual desire disorder (HSDD) or sexual dysfunction is a condition that reduces a person’s interest in sex. People who suffer from it have a lack of sexual fantasies and desire that causes distress and relationship issues. It affects up to 30% of women and 15% of men .
Many factors can affect HSDD, and some doctors will consider supplements alongside lifestyle and psychological interventions. Some evidence suggests that tribulus is a potential supplement option for both sexes. More evidence supports its use in women with reduced sexual desire or other types of sexual dysfunction .
In two trials of 76 women with reduced sexual desire, taking 750 mg/day tribulus for up to 4 months improved libido, orgasm, and satisfaction from sex. Another trial of 30 women found similar results using lower doses of a tribulus extract (7.5 mg/day) for 4 weeks [24, 25, 26].
In two studies of 90 women with sexual dysfunction, taking 750 mg/day tribulus improved sexual function and libido. This suggests tribulus might be effective in both premenopausal and menopausal women [20, 27].
Interestingly, tribulus may also increase sexual function in men – mainly by increasing desire and helping men overcome erectile dysfunction (ED).
In a 12-week trial of 172 men with ED and reduced sexual desire, taking a higher dose of tribulus (1,500 mg/day) improved satisfaction from sex, orgasm, and libido. Two other studies of 100 men with ED found lower doses (750 mg/day) for 3 months equally improved sexual function [28, 29, 30].
However, in a trial of 30 men with ED, 800 mg/day of tribulus didn’t work better than placebo .
Despite its popular use as a male libido enhancer, stronger evidence supports the use of tribulus in women with reduced sexual desire. And although it does offer some sexual benefits to men, the findings are weaker and less conclusive .
Possibly Ineffective for:
Athletic Performance and Muscle Mass
Despite its use in exercise–enhancing supplements, tribulus likely has neither performance–enhancing nor muscle–building effects.
The evidence is mixed, especially when it comes to healthy men with normal testosterone levels and sexual function. Future studies should use standardized extracts, as the effects may also vary depending on the concentration and type of active compounds.
However, 450 mg/day of Tribulus did not affect lean mass in another 5-week study of 22 elite athletes .
Tribulus caused weight gain in rats by raising testosterone levels, but it failed to affect testosterone in humans. In one study of 65 men with poor semen quality, tribulus decreased body fat and increased lean mass [33, 39].
Although tribulus is often advertised for increasing testosterone levels, research does not support its effectiveness for this use.
Studies have found that tribulus increases testosterone levels in rats, mice, and primates. But the same line of research has not been fruitful in humans. On the contrary, tribulus did not increase testosterone levels (free or total) in multiple studies in men with either low or normal testosterone levels [19, 40, 41, 42, 30, 43, 28, 44].
In two studies of 100 older men with low testosterone, 750 mg/day of tribulus did significantly raise total and free testosterone levels. Both studies had the same authors and used people from an outpatient clinic at Cairo University. Their findings were never replicated [30, 29].
It’s unlikely that Tribulus increases testosterone levels in healthy men or women with normal sex hormone levels. More research is needed to confirm tribulus is able to increase testosterone in aging men with low levels.
Dihydrotestosterone (DHT) is a more potent form of testosterone that gives men their characteristic facial and body hair growth. On the other hand, excessive DHT is also implicated in baldness in men.
Taking 750 mg of Tribulus increased DHT levels by 27% over the course of 12 weeks in a study of 65 men. However, another 10-week study of 15 men found no change in DHT levels after supplementing with 1,250 mg/day of Tribulus [39, 45].
Tribulus given by an injection in the vein increased DHT levels by 31% in primates and by 32% in rabbits .
Overall, larger clinical studies are needed to determine the effects of tribulus on DHT and its health implications.
The effects of tribulus on cholesterol levels are mixed. Some evidence suggests that this herb does not improve cholesterol in humans.
In a couple of clinical studies, the effect of tribulus appeared to be mixed. For example, two studies found a strong effect. In a trial of 98 women with diabetes, 1 g/day of tribulus for 3 months reduced total and LDL cholesterol levels. In another trial of 75 people, 3 g/day of an Ayurvedic tribulus formulation reduced total cholesterol levels by 10% over the course of four weeks. However, the ingredients in this formulation were not specified [46, 47].
On the other hand, taking 750 mg/day of tribulus didn’t affect cholesterol levels in one 12-week trial of 180 people. However, the study included participants with normal cholesterol levels. It is theoretically possible that this plant only affects raised levels in people at risk of heart disease, though much more research is needed .
In rabbits, tribulus decreased total, LDL, and HDL cholesterol, and triglycerides. Tribulus also protected blood vessels from damage caused by a cholesterol-rich diet in animals and decreased total and LDL cholesterol and triglycerides in rats and chickens. These effects have not been proven in humans [49, 50, 51, 52].
Insufficient Evidence for:
The following purported benefits are only supported by limited, low–quality clinical studies. There is insufficient evidence to support the use of tribulus for any of the below–listed uses.
Remember to speak with a doctor before taking tribulus supplements. Tribulus should never be used as a replacement for approved medical therapies.
Fertility In Men
Infertility is a global problem that affects 8 – 12% of couples worldwide. Low sperm count and poor sperm quality (movement and shape) account for more than 90% of male infertility cases. Tribulus is traditionally used to combat infertility issues in men, although proper scientific studies are still lacking to support this use .
Initially, scientists uncovered that tribulus increases sperm production in rats. They also looked at its potential mechanism in a cell study to see how it might affect sperm quality and survival time [54, 55].
Two clinical studies examined its effects in men with infertility. In one low-quality Ayurvedic study, taking 12g/day of tribulus granules for 60 days improved sperm quality in 63 men with low sperm count. The exact content of these granules was not specified .
In another study of 65 men with infertility, supplementing with 250 mg/day of tribulus for 12 weeks increased sperm count and quality .
Therefore, large-scale studies are needed. The current evidence is mixed and insufficient to determine whether tribulus improves sperm count and quality in men with infertility.
Dehydroepiandrosterone (DHEA) is a weak anabolic (muscle-building) hormone made in the adrenal glands. The body uses DHEA to make sex hormones, testosterone or estrogen. It circulates in two forms: DHEA and DHEA sulfate (DHEAS). DHEAS is usually measured because it is found in much higher concentrations in the circulation.
In 245 men, 750 – 1,500 mg/day of tribulus didn’t change in DHEAS levels after 12 weeks. In 106 women, on the other hand, 750 mg/day increased DHEA levels over the course of 90 days. Lastly, in monkeys tribulus IV injections increased DHEAS levels by 29% [28, 39, 20, 42].
Based on the evidence, it’s very hard to say whether tribulus boosts DHEA. Some scientists consider that its active steroid saponin, protodioscin, is converted to DHEA in the body. This theory suggests that tribulus may increase sex hormones indirectly, by raising DHEA. Although plausible, this theory remains unproven. More research is needed .
Blood Pressure and Heart Rate
Tribulus is traditionally used for heart-related health problems. Proper clinical trials are lacking to determine the effects of tribulus on blood pressure and heart rate in humans.
In mice with high blood pressure, Tribulus reduced blood pressure. Scientists suspect it might act by decreasing the activity of angiotensin-converting enzyme (ACE). ACE is an enzyme that increases blood pressure by constricting blood vessels. Drugs commonly prescribed for high blood pressure (called ACE inhibitors) act on this pathway [56, 57].
Scientists are also investigating the effect of saponins from tribulus on heart cells exposed to harmful chemicals in dishes. They are looking to determine the impact of tribulus on antioxidant levels, oxidative stress, and blood clotting in rat hearts and cells deprived of oxygen [58, 59, 60, 61, 62].
Blood Sugar Levels
In a trial of 98 diabetic people, 1 g/day of tribulus for three months reduced fasting blood sugar and HbA1c, a long-term marker of blood sugar control. Multi-center, large-scale studies are needed to determine the effects of tribulus on blood sugar .
Tribulus reduced blood sugar levels in diabetic mice, but these findings can’t be extrapolated to humans. Scientists believe that saponins and cinnamic acid found in this herb block enzymes that digest starches and sugars, which might prevent blood sugar levels from spiking after a meal. Future research should also determine whether it increases insulin levels, which helps shuttle sugar from the blood and into the cells [63, 64, 65, 66].
Evidence is still lacking to support the use of tribulus for blood sugar control in people with diabetes.
Lacking Evidence (Animal and Cell Studies)
No clinical evidence supports the use of tribulus for any of the conditions listed in this section.
Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies listed below should not be interpreted as supportive of any health benefit.
Kidney stones occur when calcium oxalate builds up and forms crystals, which bind to kidney cells and injure them. Scientists are investigating how extracts of tribulus fruit might reduce calcium oxalate from clumping and forming crystals in kidney cells. Some researchers suspect that tribulus increases the flushing of fluids with the urine, which may help clear kidney stones [67, 68].
Quercetin and kaempferol in tribulus are hypothesized to decrease the activity of the enzyme that forms oxalate (glycolate oxidase). In rats with kidney stones, tribulus reduced the growth of the stones and prevented damage to the kidneys [69, 70].
The combination of Tribulus and an Ayurvedic herb called Boerhaavia diffusa reduced the growth of kidney stones and improved kidney health in rats .
In a rat study, tribulus increased the release of minerals and fluids from the body similar to a diuretic drug (furosemide). However, this type of diuretic effect would theoretically only be beneficial in people with kidney stones or high blood pressure, while in healthy people it might trigger slight electrolyte imbalances .
The effects of tribulus on kidney health and kidney stones in humans have yet to be investigated.
Pain & Arthritis
In one rat study, Tribulus reduced pain due to physical injury to a similar degree as aspirin. It also reduced pain in rats with arthritis and osteoarthritis. Scientists posit that this plant might work by lowering damage to the joints and bones and decreasing levels of inflammatory molecules such as TNF-α and IL-6. This theory remains unproven [72, 73, 74].
Scientists are investigating the effects of tribulus on inflammatory and allergic skin reactions. An antioxidant found in its fruit – called rutin – suppresses an overactive immune response in the skin. Applying the fruit extract to the skin of mice reduced inflammation. It worked by preventing the activation of mast cells, immune cells that drive skin inflammation and cause redness [75, 76].
Other research teams claim its potential anti-inflammatory properties may go beyond “skin-deep.” In one study, tribulus reduced inflammation and tissue damage in mice with pancreas inflammation. It had similar effects in the colon in mice with inflammatory bowel disease [66, 21].
Whether tribulus could help people with IBS is still unknown, since its effects on inflammatory disorders in humans have not been investigated.
Scientists are exploring whether tribulus prevents the death of human skin cells exposed to UVB radiation by preventing the activity of the pro-inflammatory protein NF-κB and increasing the activity of DNA-repairing genes .
Creams and lotions made from tribulus roots may soon be formulated, but clinical research is needed.
Some researchers found that tribulus may increase the activity of melanocyte stimulating hormone (MSH) in hair follicles in the lab. MSH increases melanin levels, which gives hair a darker color. Animal and human trials need to determine whether it can prevent or reduce greying hair, based on this potential mechanism .
A couple of research groups aim to find out if tribulus is active against the following microbes in cell culture:
- Bacteria that cause cavities and tooth plaque (including Streptococcus mutans and Actinomyces viscosus) .
- Candida albicans and another small yeast that can cause respiratory problems in humans (Cryptococcus neoformans) .
Lastly, acetylcholinesterase is an enzyme that breaks down the neurotransmitter acetylcholine. This neurotransmitter orchestrates cholinergic activity in the body and is vital for memory, learning, alertness, and attention. Tribulus weakly-blocked the activity of acetylcholinesterase in a cell study, but its impact on acetylcholine in humans is completely unknown .
Liver and Kidney Health Concerns
On the one hand, some studies point to the liver- and kidney-protective benefits of tribulus. In mice, it lowered levels of a marker of liver damage (the enzyme ALT), reduced oxidative stress, and increased levels of the antioxidant glutathione in the liver, and protected the liver and kidneys from damage due to toxic substances [86, 87, 88, 89].
However, other studies suggest that tribulus may damage the liver and kidneys. In one study, Tribulus damaged the kidneys of rats. Goats that were fed high-dose tribulus experienced damaged liver and kidneys, while sheep fed 80% tribulus and 20% hay and wheat were left with similar damage (and increased liver enzymes) [90, 91, 92].
The most serious recorded case is of a man who drank 2 L of tribulus water had dangerously high AST and ALT levels. His kidneys started to suffer and he experienced seizures. The symptoms improved once he stopped taking tribulus. The exact dosage he was taking remains unknown. In another study, 750 mg/day of tribulus only mildly raised the liver enzyme AST (by 5%) [93, 30].
People who have liver or kidney damage are advised to stay away from tribulus supplements and carefully monitor liver enzymes and other markers of liver and kidney health.
Limitations and Caveats
Although it looks to be promising for a couple of conditions, many of the benefits of Tribulus are yet to be confirmed by clinical trials.
Tribulus doesn’t increase testosterone in healthy men and its effectiveness in men with low testosterone needs to be confirmed.
Supplement Forms & Dosage
Although tribulus can be supplemented as powdered root or fruit, extracts are much more common. Extracts are usually standardized to contain 15-60% total saponins (~45% is typical) and at least 6% protodioscin [39+, 4+, 30+].
Tribulus varieties that grow in eastern Europe have much higher protodioscin (and much lower tribulosin) levels than those grown in India and Vietnam. If you’re seeking libido enhancement, protodioscin is the most important compound you should look for [94+].
Tribulus is sometimes combined with other herbs, such as:
- Boerhaavia diffusa in the supplement formulation Unex, used for kidney stones [71, 95].
- Sea oak kelp (Ecklonia bicyclis) and D-glucosamine, in a formulation called Tradamixina. This product is used for increasing libido and sexual function and improving urinary issues in men with benign prostate hyperplasia [96, 97].
Dangerous, Laced Products
Due to the lack of regulation in the supplement industry, it was discovered that some tribulus products were contaminated with anabolic steroids. As is usually the case, the banned steroids weren’t listed on the label. This may result in unintentional doping violations in athletes. The Australian Institute of Sport classifies tribulus as a substance with “high risk of contamination” that should not be used by athletes .
Side Effects & Precautions
Common Side Effects
The following side effects have been reported in clinical trials:
- Abdominal pain
Two cases of kidney damage (nephrotoxicity) from tribulus tablets or tribulus water have been reported.
Tribulus fruit should not be eaten. Consuming the spine-covered fruit has been reported to cause serious respiratory problems (pneumothorax and bronchial polyp).
Tribulus increased prostate specific antigen (PSA) levels by 20% in a study of 70 men who took 750 mg daily. PSA may be higher in men with prostate cancer and other prostate disorders and is sometimes used by doctors to screen and monitor these conditions .
Ulcers are sometimes caused by long-term, high-dose NSAIDs. In a comparison study in mice, Tribulus reduced pain similar to the NSAID aspirin, but it still caused ulcers (though reportedly less than aspirin) .
Blood Sugar-Lowering Drugs
Blood Pressure-Lowering and Heart Rate-Lowering Drugs
Tribulus may reduce blood pressure and heart rate. The combination of blood pressure- and heart-rate-lowering drugs may further lower blood pressure and heart rate .
Tribulus may act as a diuretic by increasing the amount of fluids and minerals the body releases in the urine. This may increase lithium levels. The combination of diuretics may further decrease fluid flushing and mineral balance .
For increasing libido and sexual function, and for lowering blood sugar, the dose of extracts in clinical trials ranged between 750 mg and 1,500 mg daily (divided into three doses) [39, 24, 25, 20, 27, 28, 29, 30, 31].
Using 12g/day of an Ayurvedic tribulus fruit powder was effective for increasing fertility in men .
Users report that Tribulus increases libido, gives them a boost of energy, and provides a general feeling of well-being. Some users report headaches and increased irritability and aggression.
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Do not consider user experiences as medical advice. Never delay or disregard seeking professional medical advice from your doctor or another qualified healthcare provider because of something you have read on SelfHacked. We understand that reading individual, real-life experiences can be a helpful resource, but it is never a substitute for professional medical advice, diagnosis, or treatment from a qualified healthcare provider.
Tribulus terrestris is a herb with a long history of use that can help improve libido and sexual function. The active compounds responsible for its effects are steroidal saponins, plant compounds that may mimic the effects of sex hormones and increase blood flow. Of these, protodioscin is the most potent. Its levels vary depending on where the plants were grown: Southeastern Europe varieties have the highest levels and Asian varieties the lowest.
Besides boosting libido, this herb may help improve fertility, balance blood sugar levels, and protect the heart. Animal research points to its anti-inflammatory and cancer-fighting potential.
Although it is often touted to increase testosterone, research strongly suggests it has no such effect in healthy men. It may boost testosterone in men with low levels and in women, but the evidence is weak.
Professional athletes should be careful when supplementing with tribulus, as they run the risk of purchasing suspicious products contaminated with anabolic steroids.
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