4) The aphrodisiac herb Tribulus terrestris does not influence the androgen production in young men.
Abstract: objective:: The aim of the current study is to investigate the influence of Tribulus terrestris extract on androgen metabolism in young males. Design and methods:: Twenty-one healthy young 20–36 years old men with body weight ranging from 60 to 125kg were randomly separated into three groups—two experimental (each n =7) and a control (placebo) one (n =7). The experimental groups were named TT1 and TT2 and the subjects were assigned to consume 20 and 10mg/kg body weight per day of Tribulus terrestris extract, respectively, separated into three daily intakes for 4 weeks. Testosterone, androstenedione and luteinizing hormone levels in the serum were measured 24h before supplementation (clear probe), and at 24, 72, 240, 408 and 576h from the beginning of the supplementation. Results:: There was no significant difference between Tribulus terrestris supplemented groups and controls in the serum testosterone (TT1 (mean±S.D.: 15.75±1.75nmol/l); TT2 (mean±S.D.: 16.32±1.57nmol/l); controls (mean±S.D.: 17.74±1.09nmol/l) (p >0.05)), androstenedione (TT1 (mean±S.D.: 1.927±0.126ng/ml); TT2 (mean±S.D.: 2.026±0.256ng/ml); controls (mean±S.D.: 1.952±0.236ng/ml) (p >0.05)) or luteinizing hormone (TT1 (mean±S.D.: 4.662±0.274U/l); TT2 (mean±S.D.: 4.103±0.869U/l); controls (mean±S.D.: 4.170±0.406U/l) (p >0.05)) levels. All results were within the normal range. The findings in the current study anticipate that Tribulus terrestris steroid saponins possess neither direct nor indirect androgen-increasing properties. The study will be extended in the clarifying the probable mode of action of Tribulus terrestris steroid saponins.
5) THE EFFECT OF FIVE WEEKS OF TRIBULUS TERRESTRIS SUPPLEMENTATION ON MUSCLE STRENGTH AND BODY COMPOSITION DURING PRESEASON TRAINING IN ELITE RUGBY LEAGUE PLAYERS.
Tribulus terrestris is an herbal nutritional supplement that is promoted to produce large gains in strength and lean muscle mass in 5-28 days (15, 18). Although some manufacturers claim T. terrestris will not lead to a positive drug test, others have suggested that T. terrestris may increase the urinary testosterone/epitestosterone (T/E) ratio, which may place athletes at risk of a positive drug test. The purpose of the study was to determine the effect of T. terrestris on strength, fat free mass, and the urinary T/E ratio during 5 weeks of preseason training in elite rugby league players. Twenty-two Australian elite male rugby league players (mean ± SD; age = 19.8 ± 2.9 years; weight = 88.0 ± 9.5 kg) were match-paired and randomly assigned in a double-blind manner to either a T. terrestris (n = 11) or placebo (n = 11) group. All subjects performed structured heavy resistance training as part of the club’s preseason preparations. A T. terrestris extract (450 mg?d-1) or placebo capsules were consumed once daily for 5 weeks. Muscular strength, body composition, and the urinary T/E ratio were monitored prior to and after supplementation. After 5 weeks of training, strength and fat free mass increased significantly without any between-group differences. No between-group differences were noted in the urinary T/E ratio. It was concluded that T. terrestris did not produce the large gains in strength or lean muscle mass that many manufacturers claim can be experienced within 5-28 days. Furthermore, T. terrestris did not alter the urinary T/E ratio and would not place an athlete at risk of testing positive based on the World Anti-Doping Agency’s urinary T/E ratio limit of 4:1.
6) The Effects of Tribulus Terrestris on Body Composition and Exercise Performance in Resistance-Trained Males.
The purpose of this study was to determine the effects of the herbal preparation Tribulus terrestris (tribulus) on body composition and exercise performance in resistance-trained males. Fifteen subjects were randomly assigned to a placebo or tribulus (3.21 mg per kg body weight daily) group. Body weight, body composition, maximal strength, dietary intake, and mood states were determined before and after an 8-week exercise (periodized resistance training) and supplementation period. There were no changes in body weight, percentage fat, total body water, dietary intake, or mood states in either group. Muscle endurance (determined by the maximal number of repetitions at 100Ð200% of body weight) increased for the bench and leg press exercises in the placebo group (p < .05; bench press ±28.4%, leg press ±28.6%), while the tribulus group experienced an increase in leg press strength only (bench press ±3.1%, not significant; leg press ±28.6%, p < .05). Supplementation with tribulus does not enhance body composition or exercise performance in resistance-trained males.
This was talen from the "dark side" of the BB forums lol it's a good read tho.
http://blog.bodybuilding.com/nnivo7/2009/04/16/tribulus-terrestris-the-choice-of-the-animal-kingdom
