Hormonal Balance
Several of the ingredients in Orexis work to raise levels of testosterone and other hormones important for the male libido and stamina. Tribulus Terrestris, a plant found throughout the world, works to increase the production of a natural male hormone called luteinizing hormone. One of the effects of luteinizing hormone is to increase the body's production of testosterone. Although a study done by Dr. Prasad in 2002 found that this herb had aphrodisiac properties in rats, its effects on humans has not been fully determined. Another herbal compound in Orexis is Damiana, which contains several chemical compounds (called alkaloids) which are thought to mimic the effects of testosterone throughout the body. Because testosterone is an important part of male libido and sexual stamina, increasing its levels in the body can lead to natural enhancement of these qualities. There are no clinical studies published in any independent journals relating to the effectiveness of Damiana as an aphrodisiac.
Blood Flow
Proper penile circulation is essential for the both the quality and duration of erections. One ingredient in Orexis, yohimbe, has been used for many years to improve blood flow to the penis. Yohimbe is thought to work via the release of a chemical signal called cyclic GMP. This signal causes the blood vessels to dilate, which increases the amount of blood available for maintaining an erection. According to the National Institute of Health, yohimbe is effective at treating male impotence. Another component of Orexis which helps control blood flow is ginseng. In addition to promoting the relaxation of the blood vessels needed for obtaining an erection, ginseng is also thought to improve athletic performance and to promote health of the nervous system, which can aid in increasing genital stimulation. A 2002 study headed by Dr. Lee at Southern Illinois University found that ginseng could help with erections in rodents. Its effects on humans are still not well documented.
Other Ingredients
Epimedium is widely used throughout Chinese medicine to improve libido, stamina, and to help rejuvenate a male's overall vitality, although its exact mechanism is not known. Muira Puama, a shrub from Brazil, is also thought to improve libido and sexuality. Finally, Orexis contains an extract made from Catuaba bark, which is thought to improve nerve stimulation. Not only can this increase sensation during sex, but it can also help prevent the fatigue of the nervous system that can sometimes occur as a result of prolonged sexual intercourse, leading to a loss of erection. The usefulness of these herbs as an aphrodisiac has not been tested clinically, however, and these theories are based primarily on "folk medicine."
