Ejaculation can occur during masturbation, sex with a partner, or both. It usually contains 0.1 to 10 milliliters of semen.
The neuropeptides oxytocin and vasopressin are released during orgasm, heightening feelings of bonding and trust between partners and maximizing the chances of a successful pregnancy. A variety of other chemicals are also released, influencing both pleasure and health.
1. Oxytocin
Oxytocin is a hormone and a neurotransmitter (a chemical that sends electrical signals from one brain cell to another). It promotes bonding and trust between sexual partners, which helps explain why so many men fall into deep sleep after having orgasm. It’s also the chemical responsible for contractions during childbirth, breast milk letdown when breastfeeding and erection in males.
The release of oxytocin during orgasm is triggered by touching, kissing, cuddling and other forms of physical affection, as well as by intimate conversations and sex. This is why oxytocin is sometimes referred to as the “love hormone” or the “cuddle chemical.”
It is released during orgasm in both women and men and has been linked to feelings of satisfaction and closeness with your partner. Oxytocin is also released during breastfeeding and promotes a sense of closeness between mother and baby.
In men, oxytocin acts on the penile erectile tissue and on tissues in the prostate that surrounds part of the urethra and bladder neck. This helps to stimulate ejaculation by promoting the transport of sperm, as well as stimulating vasopressin VIa receptors to trigger a sphincter spasm. Oxytocin is also a potential treatment for premature ejaculation. It was found that oxytocin applied to the prostate and urethra reduced premature ejaculation in men with spinal cord injury. The results suggest that oxytocin may be used as an alternative to penile vibratory stimulation or electroejaculation in treating this condition.
2. Vasopressin
This hormone is released by the brain during sexual arousal in both men and women. It helps to control aggression and memory, but also constricts blood vessels. It is secreted in the hypothalamus when sex causes arousal, and it is also why men feel a surge of desire for their partners. Interestingly, vasopressin may also explain why men are more likely to become jealous of their partner’s attention.
During orgasm, the brain releases a slew of neurochemicals including dopamine, which is responsible for feelings of pleasure, reward and motivation. Dopamine is produced in the ventral tegmental area of the brain, and it is released into other parts of the brain, including the nucleus accumbens and prefrontal cortex. During orgasm, activity in these areas of the brain decreases while the limbic part of the brain becomes more active.
After an orgasm, semen is ejected from the testicles. This happens as a result of contractions in the pelvic floor muscles, prostate gland and the seminal vesicles. The testicles then retract back into the scrotum. Men also release a cocktail of chemicals that cause the penis to expand and contract, which results in the production of fluids that are released through the anus and into the urethra. This is a necessary process for the reproductive system to function, and it also explains why the head of the penis feels sensitive or uncomfortable after an orgasm.
3. Serotonin
Serotonin is a neurotransmitter that sends signals between nerve cells in the brain. It’s important for regulating our mood, and it may also play a role in sexual satisfaction. Serotonin is made from an essential amino acid called tryptophan, which must enter our bodies through the foods we eat. It’s possible that some medications for depression may affect serotonin levels, and thus, our sexual satisfaction.
During orgasms, the body releases chemical messengers that cause us to feel pleasure and excitement. These include vasocongestion (the swelling of body tissues), myotonia (the involuntary flexing or contraction of muscles) and endorphins. These chemicals cause the blood to flow into erogenous areas of the body, which can lead to ejaculation.
Another chemical that is released during orgasms is dopamine. Dopamine is produced in a part of the brain called the ventral tegmental area. It communicates with other parts of the brain that assess how well our human needs are being met, such as oxytocin and vasopressin.
When we reach climax, activity in other parts of the brain increases as well, including the amygdala and prefrontal cortex. This suggests that our heightened emotions during orgasms may have something to do with memory and decision-making. Additionally, during climax, cortisol is decreased, which can lower stress levels. This reduction in stress and release of dopamine might be why we often feel sleepy after orgasms.
4. Dopamine
The brain produces a variety of neurotransmitters, and dopamine is one of them. It’s made in a part of the brain called the substantia nigra (sub-STAN-sha NIGH-ra), which sits near the center of the brain. When you orgasm, this area lights up, indicating that it’s time for a big O! Other areas of the brain light up during orgasm, including the genital sensory cortex, which registers touches to the body’s nether regions, and motor areas that help control movement. And finally, the hypothalamus helps coordinate arousal and sexual responses. In fact, depression is associated with a blunted reward signal in this same region of the brain,1 which may explain why so many people who suffer from the disorder have trouble with their sexual responses.
When you orgasm, you experience fast muscle contractions in the genital and anal area. These contractions cause fluid from the penis to flow into the urethra, where it enters your body as semen. This process is called ejaculation, and it occurs in both males and females. At the peak of orgasm, oxytocin is released by neurons in the paraventricular nucleus (PVN) into the bloodstream and to the spinal cord. Oxytocin is thought to stimulate arousal and promote feelings of closeness, trust, and love between partners.
Orgasms also turn off a part of the brain called the orbitofrontal cortex, which makes decisions about what’s right and wrong. This is why you might find yourself doing things during a climax that you wouldn’t otherwise do.
