I like to surf around at various health and fitness websites because it not only lets me help answer peoples questions but it also allows me get an idea of what people are curious about. Over the last several months I’ve been noticing online chatter about Tribulus terrestris as a testosterone booster. I was a little surprised because tribulus terrestris was big in the early 1900′s and then fell out of favor when people realized it didn’t work. But maybe things have changed since I last reviewed the research so let me now take a fresh look at the tribulus terrestris research and see if there is anything new going on.
Notice the amounts of tribulus used in the studies below. I’m telling you the amounts so you can compare it to what is in your tribulus supplement. After reading this, you may want to check out what happened when I took tribulus for a few weeks.
What is tribulus?
Tribulus or tribulus terrestris (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. Tribulus, likewise, is Latin for “to tear”, another reference to the plants ability to do damage.
Tribulus trivia: Tribulus also 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.
Does tribulus raise testosterone?
The theory behind tribulus is that it’s supposed to elevate luteinizing hormone, which in turn sends instructions to the testes causing them to make testosterone. More testosterone might mean more muscle growth if combined with proper exercise like weight lifting. In theory it all sounds plausible. Fortunately, there is published research on tribulus so let’s take a look at it.
One randomized, placebo controlled tribulus study published in the Journal of Strength and Conditioning Research in 2007 tested tribulus 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.
After the study, the researchers found that tribulus did not improve strength or muscle mass or decrease body fat any better than those who did not get tribulus. In addition, tribulus did not cause any change in the testosterone to estrogen ratio (T/E ratio). In other words, tribulus did not raise testosterone either.
In an earlier tribulus study published in 2001, researchers gave either tribulus or a placebo to 15 healthy weight lifters (18 – 35 years of age). This study was published in the International Journal of Sports Nutrition and Exercise Metabolism. The amount of tribulus used in this study was 3.21 mg per kilogram of body weight.
Translation: A kilogram is 2.2 pounds. So, for example, if you weighted 180 pounds, this equals 82 kilograms. Based on this study, an 82 kg person would get 82 x 3.21 mg = 263 mg of tribulus terrestris.
All subjects performed a periodized weight lifting program (split routine) 3 days per week that worked all major muscle groups. At the end of this study tribulus did not cause any significant changes in body weight and it did not reduce body fat. Both groups – placebo group and tribulus group – improved strength and endurance.
Ironically, those who got the placebo experienced a greater amount of muscle endurance in the bench press and leg press than did those who received tribulus. Those getting tribulus did improved muscle endurance on the leg press only - but it was less than those who got the placebo. This study did not measure testosterone levels.
In a study published in 2000 in the International Journal of Sports Nutrition and Exercise Metabolism, 20 young men were given a supplement (called “Andro 6″) that contained a variety of ingredients including 750 mg of tribulus. Subjects either received Andro 6 or a placebo. All subjects then lifted weights 3 days per week for 8 weeks. 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.
Tribulus side effects
Tribulus terrestris doesn’t appear to have been studied very much in humans about what its side effects might be. Some lab rat research 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. Other research - again from lab rats – hints that tribulus may lower blood sugar. In theory, this may be a problem for diabetics.
One case study also noted that a weight lifter developed gynecomastia (male breasts) after taking a tribulus supplement. It’s hard to say how likely this is given that the prevalence of gynecomastia among weight lifters who use tribulus is unknown.
11/7/11. Update. I conducted an experiment with tribulus on myself to see if it worked. There was an effect – but it was not what I was expecting.
Tribulus and sex
Given the rep that Tribulus has for raising testosterone, it’s natural that this herb would be used in male enhancement supplements as well. I searched the National Library of Medicine for
- Tribulus erection
- Tribulus sex
I highlight the following studies as an example the types of research that is currently published.
In a 2013 study titled , Effects and Mechanism of Action of a Tribulus terrestris Extract on Penile Erection, tribulus helped improve erections in rabbits (8 rabbits were used) both when the rabbits where given tribulus orally, as a supplement, as well as when isolated cells were incubated in tribulus solution.
In a 2012 study titled Evaluation of the aphrodisiac activity of Tribulus terrestris Linn. in sexually sluggish male albino rats, Tribulus improved sexual activity in lab “sexually sluggish” lab rats.
Other similar studies are also available, but since they don’t involve people, I won’t mention them.
What I did not see were any studies on humans. Given the general thinking online that tribulus helps erections, why isn’t there any human studies showing it works or doesn’t work?
Given the lack of human research, I don’t think anyone can say if tribulus helps erections or not.
Tribulus side effects
I think in most healthy people tribulus is probably safe. That said, I personally noticed a strange side effect when I took tribulus for a few weeks so see my experiment with tribulus for more info.
In a case report from 2004 a male bodybuilder was treated for gynaecomastia (male breast enlargement) after taking an herbal supplement containing tribulus. There is also some speculation that tribulus might raise blood sugar levels. This may be an issue for diabetics who use tribulus supplements.
Does tribulus work?
As I first told people in my book Nutritional Supplements: What Works and Why, I personally don’t feel that bodybuilders or strength trainers need tribulus. I made that statement based on the peer reviewed evidence and this revisiting of the tribulus research reinforces my opinion.
In all fairness, I must say however that the tribulus terrestris research conducted so far is, for the most part, less than spectacular. Most studies either don’t last long enough or use far too few people for my tastes. I would love to see a tribulus study that is at least 6 months long and had 100 or more people (who are familiar with strength training) and who receive amounts of tribulus greater than has been used in studies to date. To my knowledge this tribulus study has not been published.
Another reputed testosterone booster supplement is Pink Magic which has Massularia acuminata so see my review of that for more information.
Also, most the research about tribulus raising testosterone is based not on people but on lab rat studies. While lack of evidence doesn’t necessarily mean something doesn’t work, based on what I see, I just dont think tribulus ready for Prime Time. There are many Tribulus products sold, but as of right now, none stand out to me as being superior to the rest. For those who are interested and want to compare prices, here is a Tribulus supplement on Amazon that has several high ratings.
What do you think?