Some recreational fishermen use tiger nuts as bait, but in other parts of the world, tiger nuts are a regular part of people's diet. Jordanian researchers write in BMC Complementary and Alternative Medicine that tiger nuts can double the level of testosterone concentration. Tiger nuts Tiger nuts aren't actually nuts, but nodules of the Cyperus esculentus plant. The nodules are edible, taste like hazelnuts and, according to traditional healers in India and the Arabian world, they enhance libido. The researchers, who work at the Jordan University of Science & Technology, did the animal study to ascertain whether tiger nuts have a pro-sexual effect. They hypothesized that tiger nuts raise the concentration of testosterone in the body. Study The researchers divided male rats into two groups: One group of highly intensive sexual behavior and another group of moderately intensive sexual behavior. Some of the animals in each group were given dried tiger nuts to eat every day for 30 days. Results Among the rats that were moderately sexually active at the start of the experiment, a dose of 2 g dried tiger nut powder per kg of bodyweight per day boosted the testosterone by 225 percent by the end of 30 days. You're welcome, thanks a lot. C = placebo group, T = tiger nut group. Tiger nut powder also boosted the testosterone level in the rats with a high level of sexual activity. Some of the animals were given 1 g of dried tiger nut powder per kg bodyweight every day [T1]; others were given double that amount [T2]. The human equivalent of the doses tried out in the experiment would be about 11-22 g tiger nut powder per day for a man weighing about 80 kg. Mechanism Tiger nuts contain relatively high quantities of zinc, quercetin [J Endocrinol. 2004 Jun;181(3):493-507.] and vitamin C [Theriogenology. 2005 Apr 15;63(7):2063-2072.] and E. The researchers think that these substances could be responsible for the effects that were measured. Conclusion "The present study supports the hypothesis that Cyperus esculentus tubers have aphrodisiac activity, enhancing male sexual libido and performance", wrote the researchers. "The observed improvements in copulatory behavior after the administration of tiger nut could be partially attributed to increased serum testosterone levels in male rats." "Future investigations are warranted to confirm these effects of tiger nut in humans."