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Tribulus Terrestris Extract: Supplement Fact or Fiction

by Bryan Haycock M.Sc., CSCS
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I first read of a tribulus terrestris product called Tribestan®, which I believe was the first tribulus terrestris product marketed to the public, in Dan Duchaine’s Underground Steroid Handbook. Since that time I have accumulated mostly second hand accounts of how, and how well, it works. Tribulus is an herbal supplement used since the late 70's in Eastern Europe. It’s purported effects include increased luteinizing hormone release and thus testosterone production, increased sperm production, increased ejaculatory volume, and increased libido. In young patients with a condition known as hypogonadism, an increase in pubic hair has also been observed. All of these effects make tribulus an interesting supplement indeed.

I should tell you at the onset that very little research has been done on tribulus outside of eastern Europe let alone without some association with a Bulgarian company called Sopharma. This makes getting access to independent studies in English very difficult because they are virtually non-existent. Most of the information I will use is provided by Sopharma of Bulgaria. Many of you know that this is the company the manufactures Tribestan®. This does not mean the data is necessarily false, it simply needs to be kept in mind when interpreting the data. Much of their research on tribulus terrestris was used to get patent approval as well as to get the product registered for distribution in the United States.

So why is there so little research done on herbal preparations with medicinal purposes here in the US? For those of you not from the U.S. or not familiar with the American Medical Model I will briefly explain. Here in the U.S. we practice what is sometimes called "rescue medicine". This refers to the fact that we put the overwhelming majority of our funds and man hours into discovering ways to save people from the brink of death. Regardless of what you here on the morning news, there is only a minute percentage of federal moneys spent on exploring preventative medicine. We claim bragging rights to a considerable number of medical innovations all designed to cheat fate (A.K.A. death). If nature has dealt you a bad hand you can count on the American Medical Association to do everything in their Hippocratic power to slip you an Ace or two under the operating table. More often than not this simply prolongs the suffering of the sick as they "enjoy" the sometimes involuntary treatment from medical doctors.

Recently there has been a push from the public to explore more holistic approaches to health. The popularity of "alternative medicine" has been growing every year for the past decade or more. Where are we getting this alternative medicine? From countries in Eastern Europe, the Middle East, and of course the Far East. In countries such as China, Bulgaria and the former Soviet Union plants with medicinal properties are taken very seriously. Scientists involved in this research are just as respected as those involved in more traditional "western" medicine, unlike here in the U.S. where they are often labeled as quacks. OK, time to step down form my soap box. Let me finish by saying that things are changing here in the U.S. and I wouldn’t be surprised to see a dramatic paradigm shift in the next couple of years as herbal medicine shows itself profitable to pharmaceutical companies. After all, where do you think the exorbitant amounts of money spent on health care go? That’s right, into the pockets of those working in the health care and pharmaceutical industry.

The original purpose for tribulus terrestris extract was as a "tonic" to treat sexual dysfunction. In animal husbandry studies tribulus extract was shown to stimulate rutting behavior (i.e. attempting to score) in rams as well as boars. When the supplement Tribestan® was given to healthy men (Milanov, 1981) in a dose of 750 milligrams per day for five days, LH and testosterone were elevated 72% and 40% respectively. As you might expect, estradiol was also elevated. In fact estradiol was elevated by 81%! The increase in testosterone is obviously what all the fuss is about, nevertheless, you can’t ignore the fact that whenever you increase testosterone you are going to increase aromatization and therefore estrogen levels. To put these changes in hormone levels into perspective, the reference range for testosterone in men is between 300 - 1,000 ng/dL. The subjects in this study started out with an average of 600 ng/dL and ended up with about 850 ng/dL. This is still well within the "normal" range for men. Estradiol on the other hand went from normal levels of about 76 pg/ml to significantly elevated levels of 137.5 pg/ml. This is well above normal levels which range from about 20-80 pg/ml in men.

So why haven’t people been reporting symptoms of elevated estrogens like bloating and gynecomastia from the use of tribulus products? My first response would be to say because they are not actually experiencing elevated estradiol levels due to the poor quality of most tribulus terrestris supplements. Lab tests (paid for by Sopharma) on several manufacturers of raw tribulus terrestris extract show that the majority don’t contain sufficient levels of protodioscine. Sopharma also went on to test various supplements said to contain tribulus terrestris extract and found most all of them to contain far less than that found in Tribestan®. Another important issue to point out is that tribulus terrestris as an herbal supplement is not the same thing as tribulus terrestris extract. Plain tribulus terrestris looks like any other herb that has been chopped up finely and dried, no different than the dried herbs you buy to cook with (Fig. 1). Tribulus terrestris extract looks much different. It is a reddish brown powder (Fig. 2).

Figure 1. Raw tribulus terrestris Figure 2. Tribulus terrestris extract
Figure 1. Raw tribulus terrestris Figure 2. Tribulus terrestris extract

Tribulus extract is extremely safe and appears to have no undesirable side effects. One of the reasons Tribulus extract doesn’t seem to have any apparent side effects in research subjects is because it doesn’t push testosterone above "upper" normal levels. The body is seemingly up-regulating aromatization to accommodate for the increase in LH and testosterone. No studies have been done to date to support this but from the changes in testosterone and estradiol respectively I would say there is a good chance this is in fact what is happening.

So to get the most out of tribulus extract I would suggest that you make sure you are in fact taking tribulus terrestris extract. Now that you know what it looks like you should have no problem finding a product that at least appears to be genuine. Although Chrysin has not exactly performed as expected, if you take enough of it you should be able to reduce the amount of aromatization caused by tribulus extract and hopefully increase testosterone levels slightly more. 1.5 -2 grams per day is a good place to start with Chrysin. Obviously an aromatase inhibitor like Arimidex would be perfect if you have access to it. ˝ tablet per day would be sufficient for the first week, then ˝ tablet every other day for the duration of time using tribulus extract should be enough. You don’t want to completely inhibit aromatase because that will lead to a reduction in GH and IGF-1 levels. As a rule of thumb take as little Arimidex as you need to control symptoms.

Prohormones such as androstenediol and/or norandrostenediol should theoretically also be helpful when taking tribulus extract. To be more precise, tribulus should help prevent or postpone the reduction of LH caused by chronic prohormone intake. I am also assuming that you would be using prohormones to elevate testosterone levels not just to "help" your workouts. This usually requires higher doses of prohormones taken throughout the day and can be accompanied by the usual unwanted side effects. Keep in mind that we are talking about taking 750-1,500 milligrams of pure tribulus extract per day to be effective. Taking less will simply be a waste of money for most people. Upon discontinuation of the tribulus product you should taper your dose over a period of at least 2-3 weeks.

Summary of Tribulus terrestris extract


Tribulus terrestris extract

NOTE: The following comments and recommendations are valid only with respect to tribulus products containing tribulus terrestris extract standardized for at least 45% steroidal saponins of the furostanol type. Of these saponins protodioscine should predominate.

Reported Benefit:

Marketed as a "testosterone booster", claims include increased Luteinizing Hormone (LH) release and thus increased testosterone production. Unfortunately claims about tribulus products usually insinuate that you will get steroid-like effects from this product. Even the most potent tribulus products will not approach the effectiveness of most synthetic androgens for building muscle.

Have controlled studies been performed?

Yes, but most research was done in Eastern Europe and was sponsored/produced by Sopharma, a manufacturer of the product. Their research shows tribulus terrestris extract to have a significant effect by increasing LH (~72%), testosterone(~40%), and estradiol(~80%).

Mechanism of action:

Tribulus Terrestris extract has been shown to stimulate LH release from the pituitary gland. It may also have some peripheral effects as manifested by increased pubic hair in some hypogonadal test subjects. It is speculated that the metabolites of protodioscine may also have mild androgenic properties. The exact mechanisms are still vague and current explanations are speculative at best.

Interaction with other nutrients?


Effective dose:

Effective doses used in clinical settings are 750-1500 milligrams per day.

NOTE: I refer to studies using Tribestan®. Other supplements with lower concentrations of active steroidal saponins would require larger doses to achieve the same effect.

Proper dosing schedule:

Take 3-4 times per day with meals. As the half-life of protodioscine is very low (~2 ˝ hours), a more frequent dosing schedule might increase effectiveness.

NOTE: In order to have an effect on male fertility supplementation must continue for at least 90 days.



Conditions where may be effective:

May be most effective at correcting a decline in LH pulsatile amplitude and/or frequency. Should be effective at returning testosterone to "normal" levels in situations where testosterone is abnormally low such as in chronic or acute hypogonadism, after a steroid cycle, while overtraining, with age associated declines in testosterone, and during extreme and/or prolonged dieting.

NOTE: Taking an aromatase inhibitor should significantly enhance the effectiveness of tribulus terrestris extract to elevate serum testosterone.

References for Tribulus terrestris extract:

  1. Vankov, S. Apropos of Tribestan pharmacology. Scientific-technical Report, 1980.
  2. Viktorov, Iv., D. Kaloyanov, Al. Lilov, L. Zlatanova, Vl., Kasabov. Clinical investigation on Tribestan in males with disorders in the sexual function MBI, 1982 (in print).
  3. Gendjeiv, Z. Studies on Tribestan carcinogenicity. Scientific-technical report, 1981.
  4. Koumanov, F., E. Bozadjieva, M. Andreeva, E. Platonova, V. Ankov. Clinical trial of Tribestan. Exper. Med. 1982, 2.
  5. Milanov, S., E. Maleeva, M. Tashkov. Tribestan effect on the concentration of some hormones in the serum of healthy subjects (Company documentation)(1981).
  6. Nikolov, R. Neuropharmacological Study on Tribestan. Scientific-technical report, 1981.
  7. Protich, M., D. Tsvetkov, B. Nalbanski, R. Stanislavov, M. Katsarova. Clinical trial of Tribestan in infertile males. Scientific-technical Report, 1981.
  8. Tanev, G., S. Zarkova, Toxicological studies on Tribestan. Scientific-technical Report, 1981.
  9. Tomova, M., R. Gyulemetova, S. Zarkova. An agent for stimulation of sexual function. Patent (11) 27584 A61K35/1978.
  10. Tomova, M., R. Gyulemetova, S. Zarkova - License (11) 27584 AGIR 35/1978.
  11. Tomova, M., R. Gyulemetova, S. Zarkova at al., License 68428/18.I.1985.

Please send us your feedback on this article.

by Bryan Haycock M.Sc., CSCS
[email protected]