Update 9/12/19. Tribulus Terrestris is one of the most popular natural testosterone boosters today. It's in MANY dietary supplements. So, does it work or is it a scam? Does it have any side effects? In this review, you will learn the results of the clinical studies on this herbal ingredient. Is it safe? Let's see what the research says.
What Is Tribulus Terrestris ?
Tribulus (also called puncture vine), is a plant that is found throughout the world. The term puncture vine stems from rumors that the plant’s thorns are able to puncture bicycle tires. The word, Tribulus, is Latin for “to tear”, another reference to the plant's ability to do damage.
Trivia: the name refers to a medieval weapon called a caltrop that was thrown on the grown during warfare to stop enemy horses from advancing. The caltrop was the forerunner of tire spikes, used by law enforcement agencies around the world to puncture car tires.
Tribulus Testosterone Clinical Studies
The theory behind this herb is it's supposed to elevate luteinizing hormone (LH), which in turn sends instructions to the testes causing them to make testosterone. More LH means more testosterone is made. And, as most know, the higher testosterone levels, might mean more muscle growth, energy, better erections etc.
In theory, it all sounds plausible but is it true? Let's look at some of the clinical studies.
In one study, researchers tested the herb in 24 elite rugby players. The players were split into 2 groups. One group got a placebo while the other received 450 mg of Tribulus Terrestris. All subjects performed the same weight lifting exercise program and the study lasted 5 weeks.
- No change in muscle mass or strength
- No decrease in body fat
- No change in testosterone levels
- No change in the testosterone to estrogen ratio (TE Ratio)
Prior to this, other researchers gave either Tribulus -or a placebo – to 15 healthy weight lifters (18 – 35 years of age). The amount used in this study was 3.21 mg per kilogram of body weight.
How much is that?: A kilogram is 2.2 pounds. So, if you weighted 180 pounds, this equals 82 kilograms. For an 82 kg person, the amount would be 82 x 3.21 mg = 263 mg of the herb.
All subjects performed the same weight lifting program 3 days per week
- Tribulus did not promote any significant changes in body weight and it did not reduce body fat.
- Both groups – placebo group and Tribulus group – improved strength and endurance.
- Those getting the placebo showed MORE muscle endurance (that's weird!)
Those receiving the placebo could perform more repetitions on the bench press and leg press than did those who received the herb. Those getting Tribulus did improve their muscle endurance -but only on the leg press- and the improvement was less than those who got the placebo. This study did not measure testosterone levels.
This investigation involved a supplement called Andro 6. This supplement contains many ingredients in addition to the 750 mg of Tribulus. The men took either a placebo or Andro 6 for 8 weeks. All worked out 3 days per week.
- The Andro 6 supplement did not raise testosterone levels or make people stronger.
- Androstenedione, however, was elevated after Andro 6 supplementation.
This study did not specifically say that Tribulus didn't work. Rather, it found that the supplement Andro 6 didn't work.
Andro 6 contained several ingredients (Saw palmetto, DHEA, androsteinedione etc.) in addition to tribulus. In theory it could be possible that the other ingredients in Andro 6 suppressed tribulus, but that is pure speculation.
In this interesting investigation, researchers looked not only at testosterone levels but also on sperm quality. This may help couples trying to get pregnant. Researchers involved 30 men with unknown fertility problems and randomly given either a placebo or 750 mg a day of Tribulus Terrestris for 3 months.
- No change in total testosterone, free testosterone, luteinizing hormone.
- Tribulus did not produce any benefits to sperm concentration or sperm mobility.
Tribulus /Testosterone Research Summary
Here's a quick rundown on the studies of human studies.
|Study||Subjects||Amount of Tribulus Used||Results|
|The effect of five weeks of Tribulus terrestris supplementation on muscle strength and body composition during preseason training in elite rugby league players||24 rugby players||450 mg/day for 5 wks||no change in strength or testosterone or body fat|
|The effects of Tribulus terrestris on body composition and exercise performance in resistance-trained males||15 weight lifters||3.21 mg/kg of body weight for 8 weeks||no change in body weight or fat loss. no better strength improvements over placebo.|
|Effects of anabolic precursors on serum testosterone concentrations and adaptations to resistance training in young men||20 young men||750 mg (contained in Andro 6 supplement)||No change in testosterone or strength vs placebo|
|Prospective Analysis on the Effect of Botanical Medicine (Tribulus terrestris) on Serum Testosterone Level and Semen Parameters in Males with Unexplained Infertility||30 men with unknown fertility issues.||750 mg for 3 months||No change in total testosterone, free testosterone, luteinizing hormone or sperm motility|
Can Tribulus Help Women?
What about women who take this herb? Can it help them? In a small study, researchers gave the herb to 2 women (yes, just 2 women) for 2 days to see what would happen. The women took 1500 mg per day.
- Tribulus did not alter testosterone, luteinizing hormone, DHEA or the testosterone to estrogen ratio (TE ratio).
Researchers gave 7.5 mg of Tribulus -or placebo – to 60 women with low sex drive for a month. The amount used was 7.5 mg per day.
Women filled out before and after questions and said the herbal ingredient helped them. The researchers, unfortunately, did not measure any hormones.
This 3-month investigation involved 40 premenopausal women who were given either a placebo or 750 mg of Tribulus Terrestris. Women filedl out questioners of sexual functioning and they also measured testosterone levels too.
- Both the Tribulus and placebo group scored similarly to each other on sexual functioning questionnaires
- Tribulus did not raise total testosterone
- Tribulus did raise free testosterone and serum testosterone
An issue with this study was that 24 of the 40 women being excluded from the study results. That's over a 50% drop out rate. This may have played a role in the outcomes.
Tribulus And Sex
Does Tribulus improve erections or help men have better sex? Given the reputation of this herb has for raising testosterone, it's natural it would be used in male enhancement supplements too. So, does it work?
Researchers gave 750 mg of Tribulus per day to 30 men complaining of having issues associated with low T and ED. The study lasted 3 months.
- Tribulus significantly raised total and free testosterone but not Luteinizing hormone
- Men also reported-via questioners -that they had better erections
This study had no placebo group. Since Tribulus is rumored to raise Luteinizing hormone, it's odd the study did not show this, in spite of seeing a boost in testosterone levels.
- Researchers gave the herb to 8 rabbits. The herb was noted to improve erections in the rabbits.
- In another investigation, the herbal extract was noted to improve sexual activity in “sexually sluggish” lab rats
Lab animal is interesting but it's not as important as human clinical research.
Tribulus Side Effects
I'm not sure about long term safety. Most studies do not last very long. While it may be safe in healthy people, I noticed a strange side effect when I took this supplement for a few weeks. see my experiment with Tribulus for more info.
Here are some basic considerations when taking this supplement. This list is not complete:
- Start with less than recommended for the first week
- Don't take if pregnant or breastfeeding
- stop taking at least 2 weeks before having surgery
- Speak to your doctor/pharmacist if you take any medications.
One report details a male bodybuilder was treated for gynecomastia (male breast enlargement) after taking an herbal supplement containing this herbal ingredient. Since the supplement contained many ingredients it's not known which was responsible for this effect.
There is some speculation tribulus might lower blood sugar levels. This may be an issue for diabetics who use Tribulus supplements.
Preliminary evidence (lab animals) hints that it may increase the size of the prostate. This may be a problem for men who have prostate issues like BPH. This effect has not been proven in humans as far as I know.
Does Tribulus Work?
I see no good proof for Tribulus being an effective testosterone booster in men. Based on the evidence I've seen, it's a dud. That said, most of the evidence stems from research that is less than spectacular. I might change my opinion if I see some better proof.