Libido (; colloquial: sex drive) is a persons overall sexual drive or desire for sexual activity. Libido is influenced by biological, psychological, and social factors. Biologically, the sex hormones and associated neurotransmitters that act upon the nucleus accumbens (primarily testosterone and dopamine, respectively) regulate libido in humans. Social factors, such as work and family, and internal psychological factors, such as personality and stress, can affect libido. Libido can also be affected by medical conditions, medications, lifestyle and relationship issues, and age (e.g., puberty). A person who has extremely frequent sexual urges, or a suddenly increased sex drive may be experiencing hypersexuality, while the opposite condition is hyposexuality. In psychoanalytic theory, libido is psychic drive or energy, particularly associated with sexual instinct, but also present in other instinctive desires and drives.A person may have a desire for sex, but not have the opportunity to act on that desire, or may on personal, moral or religious reasons refrain from acting on the urge. Psychologically, a persons urge can be repressed or sublimated. Conversely, a person can engage in sexual activity without an actual desire for it. Multiple factors affect human sex drive, including stress, illness, pregnancy, and others. A 2001 review found that, on average, men have a higher desire for sex than women.Sexual desires are often an important factor in the formation and maintenance of intimate relationships in humans. A lack or loss of sexual desire can adversely affect relationships.
Although the last days of the menstrual cycle are marked by a constant testosterone level, womens libido may get a boost as a result of the thickening of the uterine lining which stimulates nerve endings and makes a woman feel aroused. Also, during these days, estrogen levels decline, resulting in a decrease of natural lubrication. Although some specialists disagree with this theory, menopause is still considered by the majority a factor that can cause decreased sexual desire in women. The levels of estrogen decrease at menopause and this usually causes a lower interest in sex and vaginal dryness which makes sex painful. However, the levels of testosterone increase at menopause and this may be why some women may experience a contrary effect of an increased libido. Psychological and social factors
Certain psychological or social factors can reduce the desire for sex. These factors can include lack of privacy or intimacy, stress or fatigue, distraction, or depression. Environmental stress, such as prolonged exposure to elevated sound levels or bright light, can also affect libido. Other causes include experience of sexual abuse, assault, trauma, or neglect, body image issues, and anxiety about engaging in sexual activity.Individuals with PTSD may find themselves with reduced sexual desire. Struggling to find pleasure, as well as having trust issues, many with PTSD experience feelings of vulnerability, rage and anger, and emotional shutdowns, which have been shown to inhibit sexual desire in those with PTSD. Reduced sex drive may also be present in trauma victims due to issues arising in sexual function.