TRIBULUS TERRESTRIS EXTRACT
Tribulus terrestris (aka Puncture Vine) is a small, ground dwelling plant covered in sharp thorns, that has many uses in traditional and modern herbal medicine. The plant however cannot be consumed raw as it's sharp thorns make attempting this quite dangerous (there has been at least one reported instance of a would-be bodybuilder puncturing the lining of his stomach after trying to eat the plant).
In any case, raw, wet plant material contains only small amounts of the plant's active ingredients - steroidal plant saponins, of which protodioscin is thought to be the major active ingredient.
For these reasons, as with many herbs, an extract must be produced before the plant can be used medicinally. Herbal extracts are normally produced by one of two methods - water extraction or alcohol extraction. The type of extraction method used depends upon the solubility of the desired chemical, with some chemicals dissolving freely in water, whilst others will only dissolve in alcohols.
The main ingredient of Tribulus terrestris extract is the steroidal saponin protodioscin, which is usually extracted using hot alcohols (normally ethanol, though propanol or butanol may also be used), although some commercial extraction procedures make use of organic solvents.
After extraction, the solvent is evaporated and the extract purified by drying in an oven. This produces a fine powder of purified extract.
Extracting the active ingredients allows for much easier concentration and standardization of the active ingredients, whose levels can then be easily determined by chemical assay. In the case of Tribulus terrestris extract, the final product is usually standardized to 20% or 40% saponins, with a ratio of 10:1 strength of the original plant material. Extracts of up to 60% saponins may also produced for laboratory use.
Tribulus terrestris extract is now very popular amongst bodybuilders and other athletes. Taken alone, it is though to increase levels of free testosterone, aiding muscle building and reducing recovery time following workouts. It is also commonly added to other ingredients to produce male sexual performance enhancing supplements, including penis enlargement pills, erection pills and products designed to stop premature ejaculation.
Evidence for the testosterone boosting (and thus aphrodisiac and performance enhancing properties) of Tribulus terrestris extract comes mostly in the form of In Vitro studies and animal tests. Laboratory studies appear to suggest that Tribulus terrestris extract does indeed produce statistically significant increases in levels of the androgens testosterone, dihydrotestosterone and dehydroepiandrosterone. The fact that this effect has been proven in rabbits, rats, mice, monkeys and certain primate species strongly suggests that a similar effect should be induced in humans. To date however, clinical trials involving human subjects have produced conflicting results, and Tribulus terrestris extract has yet to demonstrate statistically significant androgen-boosting effects in human males.