An aphrodisiac is an agent which is used in the belief that it increases sexual desire. The name comes from Aphrodite, the Greek goddess of sensuality. Throughout history, many foods, drinks, and behaviors have had a reputation for making sex more attainable and/or pleasurable. However, from a historical and scientific standpoint, the alleged results may have been mainly due to mere belief by their users that they would be effective (i.e., the placebo effect). In particular, medical science has not substantiated claims that any particular food increases sexual desire or performance.
Some aphrodisiacs gain their reputation from the principles of sympathetic magic, for example oysters, due to their shape. The same factor explains the trade in the phallic-looking horn of the rhinoceros, a trade which is seriously endangering the animal. Other animal-based aphrodisiacs gain their reputation from the apparent virility or aggressiveness of the animal source, such as tiger penis (a reputation which is similarly endangering to that species).
Libido is clearly linked to levels of sex hormones, particularly testosterone. When a reduced sex drive occurs in individuals with relatively low levels of testosterone (e.g., post-menopausal women or men over age 60), testosterone supplements will often increase libido. Approaches using a number of precursors intended to raise testosterone levels have been effective in older males, but have not fared well when tested on other groups. Other anabolic steroids such as trenbolone which mimic the effects of testosterone may also cause increased libido in users, although side effects such as testicular atrophy are likely to decrease libido, possibly permanently, following prolonged use of these hormones.
Yohimbine is the main alkaloid of Yohimbe. Yohimbe, but not Yohimbine, is often popularly referred to as a "weak MAO inhibitor" although no sources are cited for this. Pharmaceutical preparations of yohimbine do not indicate that the drug, which is approved in the US for treatment of impotence (under such brand names as Yocon,Yohimex, Aphrodyne and Viritab), is an MAO inhibitor. Its main action is as a alpha-adrenergic antagonist, by which yohimbine may increase genital bloodflow and both sexual sensitivity and excitation in some people. Preparations of yohimbe bark are available over-the-counter and should be used with caution. The unrefined yohimbe bark contains several active alkaloids besides yohimbine. Side effects can include rapid pulse, sweating, and anxiety reactions in susceptible people. Pharmaceutical preparations of yohimbine can also produce these side effects at higher doses, but are available in standardized doses which allow the patient to dose in a controlled fashion. Some patients report a cumulative prosexual effect using the drug over time.
Compounds that activate the melanocortin receptors MC3-R and MC4-R in the brain are the first class of actually effective and selective aphrodisiac drugs. One compound from this class, bremelanotide, formerly known as PT-141, was undergoing clinical trials for the treatment of sexual arousal disorder and erectile dysfunction. It was intended for both men and women. Preliminary results proved the efficacy of this drug, but the development was discontinued due to its side effect of increasing blood pressure. The related compound PL-6983 will now be developed instead.
There is some debate in lay circles as to whether a chemical called phenylethylamine present in chocolate is an aphrodisiac. There is some evidence to support the theory that phenethylamine release in the brain may be involved in sexual attraction and arousal, but this compound is quickly degraded by the enzyme MAO and so it is unlikely that any significant concentrations would reach the brain when phenethylamine is taken orally.
Stimulants affecting the dopamine system such as cocaine and amphetamines (e.g. methamphetamine, aka crystal meth) are frequently associated with hyperarousal and hypersexuality, though both may impair sexual functioning, particularly with long term use. A newer dopamine reuptake inhibitor MDPV has also been noted to have characteristic hypersexual effects.
Some directly acting dopamine agonists may also cause increased libido, although they can also cause various side effects. Pramipexole is the only dopamine agonist used in medicine as an aphrodisiac, and is sometimes prescribed to counteract the decrease in libido associated with SSRI antidepressant drugs. The older dopamine agonist apomorphine has been used for the treatment of erectile dysfunction, but is of poor efficacy and has a tendency to cause nausea. Other dopamine agonists such as bromocriptine and cabergoline may also be associated with increased libido, as can the dopamine precursor L-Dopa, but this is often part of a spectrum of side effects which can include mood swings and problem gambling and so these drugs are not prescribed for this purpose.
Some psychoactive substances such as alcohol, cannabis, methaqualone, GHB and MDMA can increase libido and sexual desire. However these drugs are not aphrodisiacs in the strict sense of the definition, as they do not consistently produce aphrodisiac effects as their main action. However, these drugs are sometimes used to increase sexual pleasure and to reduce sexual inhibition.
Anti-erectile dysfunction drugs, such as Viagra and Levitra, are not considered aphrodisiacs because they do not have any direct effect on the brain, although increased ability to attain an erection may be interpreted as increased sexual arousal by users of these drugs.
Some natural items purported to be aphrodisiacs when ingested, or applied to the body.
Some newly introduced exotic foods often acquire such a reputation, at least until they become more familiar; for example: