A recent study found that the combination of LJ100 (by HP Ingredients), a Eurycoma longifolia extract traditionally used as a energy enhancer,  and antioxidant Polygonum minus significantly enhanced male sexual performance compared to a placebo (Evid Based Complement Alternat Med. 2014;2014:179529.Epub 2014 Jan 12). 

A total of 26 healthy men between the ages of 40 and 65 participated in the 12-week study. Participants were randomly separated into two groups. The active group received 200 mg of LJ100 and 100 mg of Polygonum minus daily. Participants had their baseline data collected and the product or placebo was dispensed. They returned for two more visits at week six and week 12 and completed diaries after each sexual intercourse attempt. Participants were instructed not to alter any current diet or exercise habits.

The active group reported a significant increase in sexual satisfaction after 12 weeks; the placebo group had a very modest increase in satisfaction. Erection time from baseline to end of 12 weeks in creased by 12 percent in the active group. Total testosterone also significantly increased in the LJ100 group.

There were no adverse side effects from the combination of LJ100 and Polygonum minus and the study concluded that the product significantly improved sexual performance after 12 weeks.