The Short Version: Tribulus is not essential in boosting testosterone levels among men, and there is little to no proof to show if it is even effective at all.
Read below for my full analysis of the studies.
Studies That Show the Impact of Tribulus on Testosterone
Tribulus is a globally occurring medicinal plant with a tap root system. Roots are the most significant part of this plant and its extract is marketed as a performance-enhancing drug. The bioactivity of Tribulus terrestris extract is attributed to steroidal saponins present in the extract. In traditional medicine, it is used to treat sexual ailments like erectile dysfunction and increasing the levels of reproductive hormones in the body.
Men with declining levels of testosterone and sportspeople are actively caving into strong marketing and consuming these supplements even though there is no scientific data supporting it. Tribulus extract has had a positive influence on testosterone levels in rats but these findings failed to translate to a similar effect on humans. There are no statistically sound scientific studies to demonstrate its role in increasing serum testosterone levels in humans…
Clinical studies using Tribulus extract in humans and rats are summarized below.
Tribulus is ineffective in treating erectile dysfunction
Study: Thirty male subjects (over 40 years of age) were recruited for this study and administered 800mg Tribulus twice daily for 30 days. The subjects in the study did not report of any other ailment and were not on any medication. Hypertensive and diabetic subjects had the blood pressure and sugar levels under control. The impact of Tribulus on erectile dysfunction was assessed by collecting International index for erectile function and serum testosterone levels at the end of the 30 day study period.
Result: Authors did not find any statistically significant difference in the international index of erectile function and serum testosterone levels in treated and placebo group.
Conclusion: Tribulus at a dose of 800mg twice a day is not effective in treating erectile dysfunction and increasing serum testosterone levels.
Source : http://www.ncbi.nlm.nih.gov/pubmed/24630840
Tribulus supplements have no effect on muscle strength and testosterone levels
Study: Twenty-eight resistance-trained males were administered Tribulus fruit extract for 4 and 8 weeks. All the subjects participated in controlled resistance training exercises 4 days per week during the course of study. Serum hormone levels were quantified for three-time points viz. basal levels, 4-week levels and 8-week levels.
Result: No significant difference was observed in the testosterone levels of the treated and placebo groups. Authors did not observe any statistically significant differences in muscle strength and body composition. Strength is a primary indicator of testosterone levels.
Conclusion: Tribulus fruit extract supplement has no effect on testosterone levels and muscle strength after 8 weeks of administration.
Source : http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2951039/
Short term Tribulus intake does not impact dope test
Study: Tribulus supplements though not scientifically proven for efficacy are being used by sportspersons for performance enhancement. This study was taken to evaluate the safety of Tribulus extracts with reference to dope test as these supplements are supposed to work by increasing endogenous testosterone levels. The levels of testosterone and epitestosterone were assayed in urine samples of volunteers in the two-day study after taking 500mg Tribulus three times a day along with a normal diet. The world anti-doping agency uses the ratio of these hormones to detect any illicit use of performance-enhancing drugs by sportspersons.
Result: Spot urine test did not detect high levels of hormones.
Conclusion: Short-term Tribulus intake does not pose any risk of testing positive in a dope test.
Source : http://www.ncbi.nlm.nih.gov/pubmed/18282674
Tribulus supplements are ineffective for gaining muscle mass and strength
Study: Twenty-two rugby players were administered with 450 mg Tribulus extract per day for 5 weeks and all the subjects underwent regular training and exercise sessions during the course of study. At the end of study muscle strength, body mass composition and urinary testosterone-epitestosterone ratios were evaluated.
Results: There was no increase in lean muscle mass, strength and testosterone levels at the end of 5 weeks of Tribulus supplementation in players.
Conclusion: Tribulus extract does not increase the testosterone levels neither does it increase any risk of testing positive in a dope test.
Source : http://www.ncbi.nlm.nih.gov/pubmed/17530942
Tribulus extract has no effect on androgenic hormones in males
Study: This four-week study was conducted on 21 young men administered 10 and 20 mg per kg body weight of Tribulus extract three times a day. During the study serum testosterone, luteinizing hormone and androstenedione were measured at different time points like 24, 72, 240, 408 and 576 hours. The main objective of this clinical study was to unravel the role of Tribulus in enhancing the levels of key reproductive hormones.
Result: The levels of all three hormones were similar in men on supplements and in untreated subjects.
Conclusion: Tribulus does not alter the levels of key reproductive hormones.
Source : http://www.ncbi.nlm.nih.gov/pubmed/15994038
Tribulus extract improves blood testosterone levels and sexual behavior in rats
Study: 18 sexually sluggish male rats were administered 50mg per kg body weight and 100mg per kg body weight of Tribulus extract and post-adaptation sexually active females were presented to these animals. Sexual behavior was recorded after two hours by an experienced observer without prior knowledge of treatments.
Result: Dose-dependent increase was observed in sexual behavior. 100mg Tribulus extract per kg body weight enhanced sexual performance and serum testosterone levels in rats. The sperm counts remain unaltered.
Conclusion: Tribulus extracts enhance the testosterone levels and sexual behavior in male rats.
Tribulus extract helps in erectile dysfunction in rats, rabbits and primates
Study: Rabbits, rats and primates (monkeys) were administered 2.5 to 30mg Tribulus extract per kg body weight for 8 weeks. At the end of study blood samples were analyzed for testosterone and dihydrotestosterone levels.
Result: Authors observed a significant increase in the hormonal levels in all three groups of animals. Testosterone levels rose by 52 % in primates and 51% in rats.
Conclusion: Tribulus extract enhances the levels of reproductive hormones in animals and can be used for erectile dysfunction treatment.
Source : http://www.ncbi.nlm.nih.gov/pubmed/18068966
There is a lot of marketing hype surrounding the use of Tribulus terrestris as a testosterone enhancer. Unfortunately, a systematic review of the published studies on human subjects reveals that these supplements are ineffective in meeting the claims of enhancing the levels of reproductive hormones and treating erectile dysfunction. However, there have been positive effects in animal studies.
I personally wouldn’t recommending using Tribulus to boost testosterone levels as there are far more effective supplements out there.