All About the Male Sex Drive

The Birds and the Bees and the Brain

A man’s sex drive is mainly in his head. Two areas of the brain, the cerebral cortex and limbic system, are vital to a man’s sex drive and performance. They’re so important, in fact, that a man can have an orgasm simply by thinking or dreaming about a sexual experience.

The cerebral cortex is the gray matter that makes up the outer layer of the brain. It’s the part of your brain that’s responsible for higher functions, such as sensation, movement, and thinking. This includes thinking about sex. When you become aroused, signals that originate in the cerebral cortex speed up your heart rate and blood flow to your genitals. They also signal the process that creates an erection.

The limbic system, part of the cerebral cortex, includes the thalamus, hypothalamus, hippocampus, and amygdala. They’re involved with emotion, motivation, and sex drive. Researchers at Emory University found that viewing sexually arousing images increased activity in the amygdalae of men. The same experiment found that men were more aroused by the images than women.


Testosterone is the hormone most closely associated with male sex drive. Produced mainly in the testicles, testosterone has a crucial role in a number of body functions, including:

  • development of male sex organs
  • growth of body hair
  • bone mass and muscle development
  • deepening of the voice in puberty
  • sperm production
  • production of red blood cells

Testosterone levels tend to be higher in the morning and lower at night. In a man’s lifetime, his testosterone levels are at their highest in his late teens, after which they slowly begin to decline.

Phases of Male Sexuality

Male sexuality begins before birth and evolves throughout life. Although there are no hard and fast timeframes, there are general phases of male sexuality.

Prenatal to Puberty

Male babies begin producing a burst of testosterone about six or seven weeks after conception. This fuels development of male sex organs. According to the Mayo Clinic, babies up to the age of five months old can have the same amount of testosterone as a post-pubescent male. Through childhood, these testosterone levels decrease until puberty.


The stage of increasing hormones starts sometime around the age 12 and lasts to ages 16 or 17, according to the Palo Alto Medical Foundation. This is when boys experience a tumultuous few years of physical and emotional change, kicked off by the hypothalamus. Among these changes are:

  • The testicles and penis grow.
  • Sperm production begins.
  • Erections increase and ejaculation occurs.
  • Facial and body hair grow.
  • The larynx, also called the voice box, grows and causes the voice to lower.
  • The sex drive escalates.


Although it no longer causes growth of the sex organs, testosterone has a role in maintaining sex drive. Although unnoticeable, testosterone levels decline slowly after age 18 or so. According to Mayo Clinic, by age 30, a man’s testosterone levels are decreasing by about 1 percent a year.

There’s a lot of discussion about sexual peak, but it’s not measured in any consistent way. In terms of testosterone levels, men peak in their late teens. It’s also true that as testosterone levels decline, it takes longer to get an erection. And it takes longer after ejaculation before a man can achieve an erection again. But the reduction in testosterone isn’t generally measurable until age 30.

Older Adults  

About the age 40, many men experience noticeable changes in their sex drive and performance:

  • Erections don’t occur as quickly or as automatically.
  • It continues to take longer to get an erection after ejaculation.
  • Blood flow to the penis is reduced, so erections are not as firm.
  • The sexual urge is not as strong.
  • The length and girth of the penis reduce slightly over time, often due to fat buildup in the arteries in the penis.

With age, an increasing number of men experience erectile dysfunction (ED). ED is the inability to get an erection or maintain an erection long enough for sex. Approximately 5 percent of 40-year-old men and up to 25 percent of 65-year-old men have ED, according to the University of Rochester Medical Center.

There are a number of reasons why men get ED, including:

  • illness, including vascular disease, diabetes, and prostate disease
  • medications such as blood pressure meds, antidepressants, and antihistamines
  • depression
  • alcohol use

There are a number of options for treating ED, including medications, surgery, and vacuum devices. If you have ED, it’s important to speak frankly with your doctor and seek solutions for the condition.

Male Hormonal Changes During Pregnancy

Did you know that a man goes through hormonal changes when his partner is pregnant? During pregnancy, a woman releases odorless hormones called pheromones. The man’s body responds by decreasing levels of the sex hormone testosterone and boosting levels of other hormones. According to a report in the Annual Review of Anthropology, men experience a change in prolactin and vasopressin in association with parenthood.


Prolactin is the hormone that stimulates the production of milk. It’s believed that increased levels of prolactin reduce a man’s sex drive at a time when it’s not needed to impregnate his partner. Instead, it improves the male’s focus on caregiving.


Also called the monogamy hormone, vasopressin represses testosterone and promotes bonding with the mother and child.


When does sex drive end? For many men, it doesn’t. The way you make love and enjoy sex will likely change over time, as will frequency. But sex and intimacy can be a pleasurable part of aging.

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