Ingredient review

Tribulus terrestris


What is it?

The plant Tribulus terrestris, commonly known as tribulus or goat’s head, has been used for thousands of years in traditional medicines. Its chemical constituents are said to have analgesic, anti-aging, anti-cancerous, anti-cariogenic, anti-inflammatory, anti-microbial, anti-oxidative, anti-spasmodic, anti-urolithic, diuretic, hepatoprotective, and immunomodulatory properties. Tribulus has known applications in sexual, cardiovascular, and anti-diabetic functions. (5)(22) A variety of tribulus products exist, containing various anatomical parts of the plant (e.g., whole plant, fruit, seeds, aerial parts, leaves, etc.). However, there is a wide discrepancy in the content of its most bioactive saponin components, particularly furostanol and spirostanol, based on the plant’s location of origin and the anatomical parts used. This may affect clinical efficacy, safety, and pharmacodynamic action. (19)

It is important to note that many tribulus products are marketed for their ability to increase testosterone, improve sexual function, and address other disorders related to male or female reproductive organs. However, a large proportion of clinical trials available to date include multi-ingredient formulations, making it unclear as to whether effects are attributable to tribulus, the other ingredients, or their combination. In this ingredient review, only single-ingredient tribulus formulations were considered.

Main uses

Raising testosterone (male and female)
Sexual dysfunction and hypoactive sexual desire


Products containing tribulus extracts are often standardized for their steroidal saponin content. Tribulus’ most bioactive steroidal component is known as protodioscin. (19)

Standardized extract containing 15% steroidal saponins (e.g., 250 mg tablet contains ~37.5 mg protodioscin) (14)
Standardized extract containing 35-45% furostanol saponins
Provided similar efficacy on erectile dysfunction measures as Tribestan® (18)
Standardized extract containing 35-45% furostanol saponins (e.g., 250 mg tablet contains ~112.5 mg furostanols); (10)
Provided similar efficacy on erectile dysfunction as EFFEX® (18)
Trib Gold
Standardized extract containing 45% steroidal saponins (e.g., 250 mg contains ~112.5 mg protodioscin) (7)

Dosing & administration

Adverse effects

A higher frequency of side effects do not occur compared with placebo or are reported at similar rates. (2)(6)(10)(15)(20) In one prospective, randomized, double-blind, placebo-controlled clinical trial that included 60 postmenopausal women with sexual dysfunction, the incidence of diarrhea was greater following tribulus intake compared with a placebo. (12)


Currently, little is known about the pharmacokinetics of tribulus and there is no available data in humans.


  • Protodioscin, one of the main active components of tribulus, is slowly absorbed with low absolute bioavailability, as shown in rodents (21)
  • Saponins possess membrane permeabilizing effects due to its amphiphilic properties that can improve the absorption of other hydrophilic and hydrophobic compounds (19)


  • Listed from highest to lowest concentrations, post-injection methyl-protodioscin was found in rodent womb, lung, kidney, liver, heart, spleen, small intestine, stomach, large intestine, ovary, skeletal muscle, fat and brain tissues (4)


  • Protodioscin may be converted to DHEA (1)
  • Methyl-protodioscin’s primary metabolite is dioscin, as shown in rats (8)


  • Methyl-protodioscin possessed a post-injection half-life of 25 to 29 minutes, (4) and protodioscin possessed a post-oral administration half-life of approximately 12 hours in rodents (21)
  • Methyl-protodioscin is excreted primarily in bile, as well as in the urine of rodents (4)


Last updated: July 28th, 2020