Bodybuilders who take 500 mg fenugreek extract daily increase the amount of bio-available testosterone in their blood, write sports scientists at the University of Mary Hardin-Baylor in the International Journal of Sport Nutrition and Exercise Metabolism. Their study suggests that fenugreek has an anti-oestrogenic effect.
Animal and human studies have shown that fenugreek has a mild anabolic effect. According to the sponsor of these studies, the Indian Indus Biotech, this is because fenugreek boosts testosterone levels, but the studies don’t actually provide proof of this.
But then there’s the study that this posting is about. It was published in 2010, and was done by a respected group of researchers in the US. Thirty young strength athletes, average 21, were the test subjects for this study.
Half of them took a daily 500 mg fenugreek extract [AI] for eight weeks. The extract was produced by Indus Biotech, in this case also the sponsor of the study. The extract was standardised for graecunins, a group of steroid-like compounds – spirostanes to be exact – found in fenugreek.
The other half of the group were given a placebo [PL].
In the eight weeks that the study lasted, both groups increased their strength by about the same amount. T1= week 0, T2 = week 4; T3 = week 8.
The lean body mass increased in both the placebo group and the experimental group by 1.6 kg.
The amount of bio-available testosterone increased by 26 percent in the experimental group, as the figure below shows: a statistically significant effect. The estradiol levels did not increase by this much, although you might have expected that to happen. Apparently the extract inhibits the conversion of testosterone into estradiol.
The figure above shows the percentage decrease of fat mass in the test subjects. The fat percentage of the athletes in the fenugreek group fell from 18.9 to 17.1 percent. In the placebo group the decrease was from 18.4 to 17.8 percent.
The researchers ascribe the decrease to the hormonal effects of the supplement.
Effects of a purported aromatase and 5α-reductase inhibitor on hormone profiles in college-age men.
The purpose of this study was to determine the effects of an alleged aromatase and 5-α reductase inhibitor (AI) on strength, body composition, and hormonal profiles in resistance-trained men. Thirty resistance-trained men were randomly assigned in a double-blind manner to ingest 500 mg of either a placebo (PL) or AI once per day for 8 wk. Participants participated in a 4-d/wk resistance-training program for 8 wk. At Weeks 0, 4, and 8, body composition, 1-repetition-maximum (1RM) bench press and leg press, muscle endurance, anaerobic power, and hormonal profiles were assessed. Statistical analyses used a 2-way ANOVA with repeated measures for all criterion variables (p ≤ .05). Significant Group × Time interaction effects occurred over the 8-wk period for percent body fat (AI: -1.77% ± 1.52%, PL: -0.55% ± 1.72%; p = .048), total testosterone (AI: 0.97 ± 2.67 ng/ml, PL: -2.10 ± 3.75 ng/ml; p = .018), and bioavailable testosterone (AI: 1.32 ± 3.45 ng/ml, PL: -1.69 ± 3.94 ng/ml; p = .049). Significant main effects for time (p ≤ .05) were noted for bench- and leg-press 1RM, lean body mass, and estradiol. No significant changes were detected among groups for Wingate peak or mean power, total body weight, dihydrotestosterone, hemodynamic variables, or clinical safety data (p > .05). The authors concluded that 500 mg of dailyAI supplementation significantly affected percent body fat, total testosterone, and bioavailable testosterone compared with a placebo in a double-blind fashion.
PMID: 21116018 [Indexed for MEDLINE]