Under stressful conditions the concentration of the hormone cortisol in the body rises. If the increase is big enough, the amount of testosterone you produce decreases and with it your libido. You can prevent this by eating a handful of goji berries every day, a Chinese animal study suggests.
The Chinese researchers, at the University of Hong Kong, experimented with a homemade goji-berry extract that they call LBP3. LBP stands for Lycium barbarum polysaccharides. The researchers extracted these from the berries using hot water. The Chinese then divided the polysaccharides into fractions, and used the third fraction for their study – hence the 3 in LBP3.
The researchers gave their rats 1 mg LBP3 per kg bodyweight per day. The human equivalent of this dose is about 10-15 mg a day. We don’t know exactly how many dried goji berries you’d need to ingest the same amount, but it may be a surprisingly small amount. A handful, we reckon.
The researchers mixed the goji extract with the male rats’ food for three weeks, and then put the animals in a cage together with sexually receptive female rats. The goji polysaccharides had a pro-sexual effect, increasing for example the number of times the male rats ejaculated. Multiple 1-mg doses had less effect. PBS = no active ingredients added.
The researchers repeated their experiment, but injected the lab animals with cortisone this time, a precursor of cortisol. The injections reduced the number of ejaculations, but not in the rats that had been given the goji extract in their food.
The cortisone injections lowered the testosterone level of the control group rats, but had no effect on the rats that had been given the goji polysaccharides.
The researchers suspect that goji blocks the deleterious effects of the stress hormone cortisol in the brain. They concluded this from in-vitro experiments with stem cells, which develop into brain cells. This didn’t happen in the cells exposed to cortisone, but did when the researchers added goji extract as well.
This study provides evidence for the pro-sexual effect of LBP in both normal animals and animals with suppressed sexual performance”, the researchers write. “Such findings support the use of wolfberry as a treatment for sexual dysfunction or as an aphrodisiac treatment.”
Polysaccharides from wolfberry prevents corticosterone-induced inhibition of sexual behavior and increases neurogenesis.
Lycium barbarum, commonly known as wolfberry, has been used as a traditional Chinese medicine for the treatment of infertility and sexual dysfunction. However, there is still a scarcity of experimental evidence to support the pro-sexual effect of wolfberry. The aim of this study is to determine the effect of Lycium barbarum polysaccharides (LBP) on male sexual behavior of rats. Here we report that oral feeding of LBP for 21 days significantly improved the male copulatory performance including increase of copulatory efficiency, increase of ejaculation frequency and shortening of ejaculation latency. Furthermore, sexual inhibition caused by chronic corticosterone was prevented by LBP. Simultaneously, corticosterone suppressed neurogenesis in subventricular zone and hippocampus in adult rats, which could be reversed by LBP. The neurogenic effect of LBP was also shown in vitro. Significant correlation was found between neurogenesis and sexual performance, suggesting that the newborn neurons are associated with reproductive successfulness. Blocking neurogenesis in male rats abolished the pro-sexual effect of LBP. Taken together, these results demonstrate the pro-sexual effect of LBP on normal and sexually-inhibited rats, and LBP may modulate sexual behavior by regulating neurogenesis.
PMID: 22523540 [PubMed – indexed for MEDLINE] PMCID: PMC3327693