Our era is the first in history, so far as we know, in which nostrums for sexual enhancement have become "politically correct" - so much so that Senator Bob Dole, a former candidate for President of the United States, has become the leading spokesman for improved erectile function. The Senator's wife, Elizabeth, also seems to think highly of her husband's prowess, having said that the touted nostrum is a "great drug." Even more amazing is that Mrs. Dole also ran for the office of President. We can only wonder whether there is some cosmic significance to all this. Surely there is a popular conception that power and potency are connected.

A pharmaceutical nostrum may very well be a great drug, but it's still a drug. Fortunately, there are alternatives that do not involve the potential for negative, even serious, consequences.

Sex is an important aspect of health and happiness: not only does it reflect underlying robustness as an effect of good health, but it probably acts, to some degree, as a causeof good health in the first place.

Dr. Jonathan Wright, author of Maximize Your Vitality and Potency for Men Over 40,recommends scientifically warranted nutritional ingredients that are known to bolster the use, release, and function of testosterone. One of these ingredients is Tribulus terrestris, a plant extract that helps elevate the male libido.

Tribulus is a ground-hugging thorn plant that bears fruit possessing sharp spines. It has been used for many centuries as a medicinal herb in Chinese and Indian Ayurvedic medicine, and for perhaps as long in Europe as well. In the Chinese tradition, Tribulushas been of value for such problems as skin irritation, insufficient milk production, itchy eyes, and urinary-tract and reproductive-tract problems in both men and women.1 In India, it has been valued as an aphrodisiac and for its benefits on the urinary tract.2 It is also thought of as a tonic, and in one study, as part of an Ayurvedic preparation, Tribulus was used to treat 50 patients complaining of lethargy, fatigue, and lack of interest in day-to-day activities. The result was an overall improvement of 45% in these symptoms.3

In the last few decades, Tribulus has come into its own in the old Soviet bloc, especially Bulgaria, where its use has created a modern legend as a libido tonic able to enhance sexual activity by improving and prolonging erections. As well, Tribulus has been found to have a stimulating effect on spermatogenesis by increasing the number of spermatozoa and their motility and viability.

The properties of Tribulus vary depending on whether the root, stem, leaves, or fruit are used. As with other botanical extracts, the composition of Tribulus may vary depending on the site and conditions of growth, including the quality of the soil. However, it is the use of standardized Tribulus leaves that has been responsible for its growing reputation as a tonic among bodybuilders and athletes, who value it for having properties similar to those of anabolic steroids, but without the liabilities.

There are several active components of Tribulus, including the steroidal saponins protodioscin and protogracillin.4 Saponins possess detergent qualities, from which they derive their name (although sapo means hair dye, it is the root of soap-related terminology), but it is their steroidal molecular structure that is thought to confer their unique biological activity.5 Another major category of Tribulus component is that of phytosterols, such as beta-sitosterol,6 which is also steroidal in activity.

When a Tribulus extract was given to eight apparently healthy men and eight healthy women, ages 28-45, in a dose of 250 mg three times per day for five days, the results were emphatic:7

  • Testosterone levels increased, on average, threefold in the men.
  • Estradiol levels increased about 1.5 times in the men. In the women, the estradiol levels increased less than in the men, but the difference was still significant.
  • Luteinizing hormone (LH) increased substantially in both men and women.
  • Follicle-stimulating hormone (FSH) increased substantially in women.

This study emphasized the impact of Tribulus on some hormones, particularly those that are most responsible for masculinity and femininity in the respective sexes. It should be stressed that the levels of the hormones studied did not appear to go beyond the physiological frames, i.e., did not disturb the normal mechanisms of hormonal regulation. Moreover, in men with serum testosterone levels below the lower limit of the norm, the physiological levels were reached after treatment, whereas in men with normal initial levels, the testosterone level was not significantly changed by the treatment.

The prosexual activity of Tribulus is not confined to sperm gymnastics, for which studies have been done on lab animals showing increased production as well as increased tenacity and viability.6 Tribulus increases libido, the desire for sex. In an animal study, its ability to act as a sexual tonic was apparent through accelerated and emphasized sexual activity: its tendency to increase testosterone levels stimulated sexual development in rams and male lambs, as evidenced by increased rutting behavior (attempting to "score").8 Tribulus has also been found to cure impotence and improve semen production in rams.5 In boars, libido and sexual reflexes were restored after long-term impotence.9

Tribulus has created a 
modern legend as a libido 
tonic able to enhance 
sexual activity by 
improving and prolonging 

Traditionally, a tonic is something that produces physical, mental, or emotional vigor. Tribulus has a tonic reputation that has been verified in the lab by increased endurance in rats.10 In humans, Tribulus has been shown to be a general stimulator, enhancing activity across a wide spectrum. In addition to improving motor activity and muscle tone, it helps restore vigor, vitality, and stamina.11 It has also been shown to intensify protein synthesis, particularly in the liver, kidney, and heart tissue of animals,12 while it enhances energy metabolism.13 The best explanation of the tonic effects of Tribulus is that its steroidal properties may enable it to regulate the secretion of antistress hormones such as cortisol, produced by the adrenal cortex.14

In the previously mentioned study done with eight healthy men and eight healthy women,7 Tribulus clearly altered the amounts as well as the balance of steroid hormones. This helps explain the prosexual (as distinct from tonic) activity of Tribulus.The hormones LH and FSH are produced in both sexes by the pituitary gland, under the control of the brain's hypothalamus. They control the functioning of our gonads - the testes in men and the ovaries in women - in complicated ways, subject to negative feedback loops (not unlike a thermostat) that maintain a proper balance between them and the sex hormones produced by the gonads. As we age, however, this system tends to become unbalanced, and testosterone and estrogen production decline. By stimulating production of LH and FSH, Tribulus apparently helps to boost sex-hormone levels as well.

But exactly how does that work? Well, the neat thing about the steroidal saponins extracted from Tribulus is that they apparently bind with, but only weakly stimulate, the receptors in the hypothalamus that detect the sex hormones. They thus partially block those receptors, inducing the hypothalamus to misinterpret the body's sex-hormone levels as being lower than they really are. The hypothalamus responds by signaling the pituitary gland to boost production of LH and FSH, and we already know the rest of that story.

When 750 mg per day of Tribulus extract was given to a total of 212 men in open clinical trials, 85% had increased libido after 30 days, and 94% after 60 days. Thus, Tribulusunquestionably stimulated sexual desire.15-17 In another study, treatment with 750 mg per day for 60 days significantly increased sperm motility in 38 men with idiopathic oligospermia (low sperm count of unknown origin).15

In another study, when varicoceles (small varicose veins within the spermatic cord) were surgically removed, men treated daily with Tribulus - either 750 mg for 60 days or 1500 mg for 90 days - were found to have significant improvement in sperm motility.16 An increased volume of ejaculate was noted in the men taking the larger dose.

Improvements in ejaculate volume, sperm count, and motility were also found in men with shrunken testes and oligospermia (not idiopathic, obviously) after receiving 1500 mg per day of Tribulus extract for 60 days.17 Higher testosterone levels were also noted.

In the same study, of 14 patients with reduced libido, 12 showed considerable improvement after 30 days (1500 mg/day), and one was slightly improved after 60 days' treatment. Libido was improved in 27 of 36 patients with chronic prostatitis. Patients who had suffered this condition for five years or more showed no improvement, yet in patients with shrunken testes and oligospermia, libido was apparently improved.

Women are included in 
the benefits of Tribulus.

Also in the same study, libido and sexual activity were improved in some patients with Klinefelter's syndrome (genetically determined underdeveloped testes), Noonan syndrome (a multiple disorder that includes undescended testes), and simple undescended testes.

Women are not excluded from the benefits of Tribulus. In an open study, one group of 36 women with nonovular menstrual cycles were given Tribulus in the range of 750-1500 mg per day on days 5 through 14 of their menstrual cycle.18 Ovulation was normalized in 67% of the women, with successful pregnancies occurring in 6%. In a parallel group of 62 women using a drug targeting the same problem of nonovulation, 39% had normalized ovulation with pregnancy, and 35% had normalized ovulation without pregnancy. From these results, it is clear that Tribulus possessed a considerably more moderate effect than the drug: 24 of the 36 women had normal ovulation restored, but only two of them became pregnant, and no effect was recorded in 12 of them. On the other hand, the women taking Tribulus had no side effects, compared to 38% of the women in the group treated with the ovulation-stimulating drug.

In the same study, another group of 50 women - 26 of whom were experiencing natural menopause and 24 of whom were in postoperative menopause, in which removal of the ovaries causes menopausal symptoms - were given standardized Tribulus, in a maintenance dose range of 500 to 750 mg per day, after higher initial doses.

The study used a crossover protocol: each of the women took in turn both Tribulus and placebo, so that by the end of the study, all 50 had been in both the treatment group and the control group. The spectrum of their symptoms, typical of menopause, included:

  • Hot flashes 50 100%
  • Sweating 39 78%
  • Depression 27 54%
  • Hyperexcitability 22 44%
  • Insomnia 41 82%
  • Anxiety 18 36%
  • Sense of heaviness in the cardiac region 30 60%
  • Arterial pressure changes 11 22%
  • ECG changes 8 16%

The women were categorized according to their level of libido as follows:

  • Normal 2 4%
  • Low 20 40%
  • Very low 28 56%
  • Total 50 100%

Whereas placebo did not alleviate any symptom in any member of the control group, Tribulus brought about some significant level of improvement in 98% (49 out of 50) of the women in the treatment group, including the alleviation of hot flashes, sweating, depression, insomnia, and anxiety. There were no significant changes in any measured hormone level, including FSH (follicle-stimulating hormone), LH (luteinizing hormone), prolactin, estradiol, progesterone, and testosterone. Tribulus was without significant side effects.

When Tribulus was coadministered with vitamins following surgery, the recovery processes were accelerated.10 These included a shortening of the postoperative period as well as maintained levels of fibrinogen, a blood-clotting protein.

Tribulus brought about a 
significant level of improvement 
in 98% (49 out of 50) of the 
women in the treatment group, 
including the alleviation of hot 
flashes, sweating, depression, 
insomnia, and anxiety.

In a larger study involving 406 subjects with heart disease, Tribulus was found to improve the symptoms of angina pectoris.19 Researchers believe that the saponins helped dilate the coronary arteries, thereby improving circulation. No side effects were noted. Even after long-term administration, blood, liver, and kidney functions were unaffected.

A testimonial to the safety of Tribulus is the fact that it has been used for centuries in Europe for hormone insufficiency in men and women. In China, its use has spanned at least as long a time, with significant applications in premature ejaculation and reproductive problems. In addition to having low acute and chronic toxicity in mice and rats,20 Tribulus administered at 50-150 mg per kg daily for 93 weeks did not induce malignant tumors.21

The fruit of Tribulus is sometimes eaten by livestock, and, as with St. John's wort, excessive consumption has been noted to cause skin rash and liver damage. However, there is no known toxicity for humans. The effects seen in livestock are unlikely to occur in humans anyway, given the large quantities required and the necessary role of ruminant digestive flora, which, of course, we do not have.22

Foremost among its benefits is that Tribulus acts as a tonic to restore and build energy, helping to increase strength and improve physical performance. Men should consider using it to increase libido and enhance potency, while women will find it to be of significant value for alleviating the symptoms of menopause. Furthermore, Tribulus can help both men and women with the problem of infertility.

The recommended amount of the principal active components, the steroidal saponins, is about 115 mg (the equivalent of a 250-mg serving of a 45% Tribulus extract) two to three times a day.


Foremost among its benefits is 
that Tribulus acts as a tonic to 
restore and build energy, helping 
to increase strength and improve 
physical performance.



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  2. Kapoor LD. CRC Handbook of Ayurvedic Medicinal Plants. CRC Press, Boca Raton, 1990, p 325.
  3. Jayaram S, et al. Tribulus. Indian Drugs 1993;30(10):498-500.
  4. Gjulemetowa R, Tomowa M, Simowa M et al. Concerning the determination of furanostanol saponins in the preparation Tribestan®. Pharmazie 1982;37(4):296.
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  9. Zarkova S. Tribestan: Experimental and Clinical Investigations. Chemical Pharmaceutical Research Institute, Sofia, 1982.
  10. Taskov M. Vitaton. Med-Biol Inf 1988;1:3.
  11. Dikova N, Ognyanova V. Pharmacokinetic studies on Tribestan - Anniversary scientific session 35 Years Chemical Pharmaceutical Research Institute, Sofia, 1983.
  12. Sheitanov M, Khristov T, Taskov M, et al. Vitaton: comparative studies on its effect on incorporation intensity of labeled amino acids in cellular proteins. Med-Biol Inf 1988;1:20-3.
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  14. Tomova M, Gyulemetova R. Steroidsapogenine. VI. Furostanol bisglykosid aus Tribulus terrestris L. Planta medica 1978;34:188-91.
  15. Protich M, Tsvetkov D, Nalbanski B, et al. Clinical trial of the preparation Tribestan in infertile men. Akush Ginekol 1983;22(4):326-9.
  16. Kumanov F, Bozadzhieva E, Andreeva M, et al. Clinical trial of the drug "Tribestan." Savr Med 1982;4:211-5.
  17. Viktorov IV, Kaloyanov AL, Lilov L, et al. Clinical investigation on Tribestan in males with disorders in the sexual function. Med-Biol Inf 1982. Cited in Zarkova S. Tribestan: Experimental and Clinical Investigations. Chemical Pharmaceutical Research Institute, Sofia, 1982.
  18. Zarkova S. Tribestan: Experimental and Clinical Investigations. Chemical Pharmaceutical Research Institute, Sofia, 1983.
  19. Wang B, Ma L, Liu T. 406 cases of angina pectoris in coronary heart disease treated with saponin of Tribulus terrestris. Chung His I Chieh Ho Tsa Chih1990;10(2):85-7.
  20. Tanev G, Zarkova S. Toxicological studies on Tribestan. Cited in Zarkova S. Tribestan: Experimental and Clinical Investigations. Chemical Pharmaceutical Research Institute, Sofia, 1985.
  21. Gendzhev Z. The carcinogenicity of Tribestan. Tr Nauchnoizsled Khim Farm Inst1985;15:241-50.
  22. Graydon RJ, Hamid H, Zahari P, Gardiner C. Photosensitisation and crystal-associated cholangiohepatopathy in sheep grazing Brachiaria decumbens. Aust Vet J 1991 Jul;68(7):234-6.