Tribulus (Tribulus terrestris) is a small, creeping plant that is native to the Mediterranean, Asia and India and is also found in the northern parts of Australia. It is well adapted to warm, dry climates and has now been declared a noxious weed in many areas of North America. Tribulus is known commonly as puncture vine due to the sharp thorns found on the plant’s seedpods.
Tribulus has a long history of use as a herbal medicine by Chinese, Unani (Arabic) and Ayurvedic (Indian) systems of medicine. It is primarily used in these systems of medicine as a diuretic and in the treatment of kidneys stones, urinary tract infections and incontinence. Ayurveda also uses tribulus to treat many different types of sexual dysfunction in men, including impotence and fertility problems.
A Bulgarian favourite
The main active components of tribulus are the steroidal saponins, thought to be the most biologically important actives as all the clinical trials from Bulgaria used extracts containing a high percentage of these. One of these steroidal saponins, protodioscin, is often used as a chemical marker to measure batch quality. Research has found that the content of protodioscin varies significantly between plants grown in different geographic regions, tribulus grown in Bulgaria contains the highest amount of protodioscin. A 1998 analysis of 20 tribulus supplements available in the US found that many of the products did not contain adequate amounts of protodioscin to offer equivalent doses to those used in research.
Protodioscin content also varies greatly depending on the parts of the plant used to make a product. Traditionally, the whole plant was used as a medicine, including the leaves, fruit and stem, however much of the modern research has used extracts made from only the leaves of tribulus, which contains the highest concentration of the saponins.
Sex, muscles and fertility
Contemporary herbalists and naturopaths use tribulus to stimulate sexual function and fertility in men and women, change hormone production and improve resistance to stress and exercise. As tribulus causes a stimulation of the body’s endogenous sex hormones, it has very wide-ranging medical applications, from use as a performance enhancer in athletes to reducing the symptoms of menopause.
Bulgarian research has demonstrated that tribulus stimulates the production of follicle-stimulating hormone (FSH) in women, which leads to an increase in oestrogen. In men, tribulus has been found to increase the production of luteinising hormone (LH), which in turn leads to an increase in testosterone levels. These actions are key to the therapeutic effects of this herb in treating fertility problems in men and women.
Fertility
Tribulus has a beneficial effect on male fertility and sexual function by stimulating the production of testosterone and DHEA, another closely related steroid hormone. Tribulus also helps improve sperm count and quality. A Bulgarian research team treated a group of 38 men with low sperm count of unknown cause with 1500mg of tribulus extract per day. After 60 days of treatment, a normalisation of the sperm profile was observed as well as an increased level of LH and testosterone and decreased oestrogen.
Tribulus is also an excellent herb for treating many different fertility problems in women. The herb helps stimulate ovulation by increasing FSH levels and can also indirectly help improve oestrogen production. One Bulgarian trial involving infertile women compared the effectiveness of tribulus, ovarian stimulant medication and both. Sixty-one per cent of the women in the group who took tribulus on days five to 14 of their menstrual cycle for two to three months began to ovulate normally and a further 6 per cent went on to conceive naturally. The group of women taking ovulation stimulants had a higher rate of conception, but there were significantly higher side-effects associated with their use.
Muscle development
The use of tribulus to boost athletic performance began after the Bulgarian weight-lifting team attributed their success to the use of tribulus throughout their training. The rationale that using a herb that has been shown to increase testosterone levels as a sports performance-enhancer makes sense, but most of the research in this area has produced inconsistent results.
One recent double blind trial found tribulus did not enhance muscle growth or exercise performance in eight men undertaking a resistance-training program. However, the authors did comment that the trial participants were already lean before the trial and better results may be seen in less lean people and in people who eat a high-protein and high-calorie diet alongside tribulus use.
Other research has shown that tribulus extract does not affect testosterone levels in healthy young men. As healthy young men have relatively high levels of testosterone, anyway, it may be that tribulus gives better results for muscle growth and sports performance in older men and men who have other risk factors for declining testosterone levels, such as being overweight, or those under chronic long-term stress.
How much?
The recommended adult dose of tribulus is as an extract equivalent to 100mg of steroidal saponins taken three times a day. For effective dosing and management of hormonal and fertility problems, treatment by a qualified naturopath or herbalist is advised.
As a word of caution, herbal medicines that contain high levels of saponins may cause reflux and stomach irritation in some people. If this occurs, tribulus should be stopped immediately. Due to the hormonal effects of tribulus, pregnant or lactating women should not use supplements containing the herb and women trying to conceive should cease taking tribulus if conception occurs.
Gerard Elms is a naturopath, nutritionist and herbalist with a practice in Neutral Bay, Sydney. He specialises in digestive disorders and men’s health. T: 02 9904 0734, E: gerardelms@gmail.com.
