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"Goathead" fruit

Puncture Vine (Tribulus terrestris), also known as Caltrop, Yellow Vine, and Goathead, is an herb used for its virilizing effects.

The plant is native to Eurasia and widely naturalized in the Americas and Australia. It can thrive even in desert climates and poor soil. In some states in the U.S., it is considered an invasive species.

Puncture Vine is a taprooted perennial that grows as a summer annual in colder climates. The stems radiate from the crown to a diameter of about 7.5 to 75 cm (3 to 30 inches), often branching. They are usually prostrate, though they may grow more upwards in shade or among taller plants. The leaves are pinnately compound with leaflets less than a quarter-inch long. The flowers of clear lemon-yellow, 0.6 cm (a quarter of an inch) wide, are pretty on the flat little patches formed by the plant. A week after each flower blooms, it is followed by a fruit that easily falls apart into four or five single-seeded nutlets. The nutlets or "seeds" are hard and bear two sharp spines, which spread less than 0.6 cm point-to-point. These nutlets strikingly resemble goats' or bulls' heads; the "horns" are sharp enough to puncture bicycle tires and to cause considerable pain to unshod feet.

The Latin name tribulus originally meant the caltrop (a spiky weapon), but in Classical times already meant this plant as well.^[1]

It has been reported that Puncture Vine seeds have been used in homicidal weapons in southern Africa; murderers smear them with the poisonous juice of Acokanthera venenata and put them where victims are likely to step.^[2]

Dietary supplement

Tribulus terrestris is being promoted as a testosterone booster for the purpose of building muscle and increasing sex drive. It does not work like DHEA and androstenedione 100, which are progenitors of testosterone. Instead, claims have been made that it enhances testosterone levels by increasing luteinizing hormone (LH) levels. LH is responsible for "telling" your body to produce testosterone. One interesting fact is that steroids suppress LH, thus reducing and sometimes shutting down the body's production of testosterone.

Independent studies^[3] have suggested that Tribulus terrestris extract does increase testosterone levels, though leaving them in the normal range, which is not thought to increase muscle development much. They have suggested that it may be beneficial for those whose testosterone is below normal.

No significant adverse effects have been reported from supplementation with Tribulus terrestris. However, some users report an upset stomach, which can usually be counteracted by taking it with food.

Common names

As is typical of weeds, this plant has many common names: bindy eye, bindii, bullhead, burnut, burra gokhroo, caltrop, calthrops, cat's head, common dubbeltjie, devil's thorn, devil's weed, doublegee, dubbeltjie, goathead, gokshura, ground bur-nut, isiHoho, land caltrop, Maltese cross, Mexican sandbur, puncture vine, puncture weed, rose, small caltrops, tackweed, Texas sandbur, yellow vine (also T. micrococcus).

External links

• Review of Tribulus supplements at ironmagazine.com

• Page on T. terrestris at the Global Compendium of Weeds

• Page from the U. S. Department of Agriculture's PLANTS database