What is oxytocin: The love hormone?

Oxytocin is a neurotransmitter and a hormone involved in childbirth and breast-feeding. It’s also correlated with empathy, trust, sexual behavior and building relationships.

It is also called the “love hormone,” since oxytocin levels increase during hugging and orgasm. As a medication it can also have implications for a variety of disorders, including depression, anxiety, and intestinal problems.

Oxytocin is a part of the brain, formed in the hypothalamus. Females usually have higher rates than males.

Important facts about oxytocin

Here are a few key points about oxytocin. More details are given in the main article.

  • Oxytocin is produced in the hypothalamus and released during sex, childbirth, and lactation to aid reproductive functions.
  • It has physical and psychological effects, including influencing social behavior and emotion.
  • Oxytocin is prescribed as a drug for obstetric and gynecological reasons and can help in childbirth.
  • Research shows that it may benefit people with an autistic spectrum disorder (ASD), anxiety, and irritable bowel syndrome (IBS).

What is oxytocin?

A mother breastfeeding her child
Oxytocin is important during childbirth and breast-feeding.

Oxytocin is a neurotransmitter, and a hormone that is produced in the hypothalamus. It is transported from there, at the base of the brain, to and secreted by the pituitary gland.

It plays a part in the functions of female reproduction, from sexual activity to childbirth and breast feeding. Nipple stimulation causes its release.

Oxytocin increases uterine motility during labor, causing contractions in uterine muscles, or womb. Oxytocin is released when the cervix and vagina begin to open for childbirth. As more contractions occur, this widening increases.

Oxytocin has social functions too. It impacts bonding behaviour, group memory creation, social recognition and other social functions.

Oxytocin as a drug

Oxytocin is used as a prescription drug under the Pitocin brand name. Oxytocin injection is often used under medical supervision to initiate or intensify birth contractions during labor, which helps to prevent bleeding after childbirth. Side effects include a rapid heartbeat and unusual bleeding.

If too much oxytocin is delivered too quickly, it can cause a rupture of the uterus.

Oxytocin can also be given after delivery or termination to make the uterus contract and control bleeding.

It may be used medically to induce a termination or complete a miscarriage.

The love hormone?

Researchers reported in 2012 that people had higher rates of oxytocin in the first stages of romantic attachment compared to non-attached individuals. Those levels continued for a total of 6 months.

Sexual activity has been shown to induce oxytocin release, which appears to play a role in erection and orgasm. The explanation for this is not fully understood, but the increased uterine motility can help sperm reach their destination in women. Some have suggested a correlation between the oxytocin concentration and orgasm intensity.

Oxytocin and emotion

Happy couple hugging each other
Oxytocin appears to play a role in social interaction and relationships between people.

Once oxytocin reaches the bloodstream it stimulates the uterus and lactation, but it can affect emotional, cognitive , and social activities once released into other areas of the brain.

One review of oxytocin research states that the impact of the hormone on “pro-social behaviors” and emotional responses contributes to relaxation, confidence and psychological stability.

Oxytocin in the brain also helps to reduce stress responses like anxiety. There are a variety of species that have experienced such impacts.

The hormone was described as “an important component of a complex neurochemical system which enables the body to adapt to extremely emotional situations.”

Is it that simple?

Researchers reported in 2006 finding higher levels of oxytocin and cortisol among women who had “gaps in their social relationships,” and more negative relationships with their primary partner. Upon menopause the participants all received hormone therapy (HT).

Animal studies found high levels of stress as well as oxytocin in voles which were separated from other voles. However, when the voles received oxytocin doses, their levels of anxiety, heart stress and depression fell, suggesting that stress increases the hormone ‘s internal production, while externally supplied doses can help reduce stress.

Oxytocin’s action obviously isn’t straightforward.

A review published in 2013 cautions that oxytocin is likely to have general rather than specific effects, and that oxytocin alone is unlikely to affect “complex , high-order mental processes specific to social cognition.” The authors also point out that a desire to cooperate is likely to be driven mainly by anxiety.

However, oxytocin does tend to be correlated with social behaviour, including maternal care, couple bonding, sexual behavior , social memory, and trust.

Behavioral effects

Oxytocin delivery through a nasal spray has allowed researchers to observe its behavioral effects.

Research published in Psychopharmacology in 2011 found that intranasal oxytocin improved social self-perception and increased personality traits such as warmth, confidence, altruism and openness.

A study published in PNAS in 2013 suggested that oxytocin may help keep men faithful to their partners by activating the centers in reward in the brain.

In 2014, researchers published findings in the journal Emotion suggesting that after receiving oxytocin via a nasal spray, people saw facial expression of emotions in others more intensely.

Psychiatric therapy

Oxytocin has been proposed to treat social phobia, autism and postpartum depression as a possible treatment.

Scientists proposed that it can help enhance interpersonal and individual well-being, and may have applications for people with other neuropsychiatric disorders.

They believe it could help people avoiding social interaction, and those experiencing persistent fear and a lack of trust in others.

Oxytocin may be helpful to children with autism, some researchers claim. A small study in 2013 suggested that levels of oxytocin in the brain affected the way 17 children perceived a series of social and non-social images.

Oxytocin can also play a part in controlling anger. Research has shown that some oxytocin receptor (OXTR) gene polymorphisms are associated with a greater tendency to react angrily to situations.

In particular, differences in the expression of OXTR genes tend to affect the regulation of the alcohol and aggressive behavior relations.

Uses

In cells lining the intestine, oxytocin appears to increase the release of prostaglandin E2 (PGE2). This helps promoting intestinal injury repair and protecting against such injury.

If confirmed, oxytocin may be a useful treatment to prevent chemo-radiotherapy-induced bowel injury, and it may be used to treat irritable bowel syndrome ( IBS).

Risk

Oxytocin’s role is complex, and not easy to pin down.

It may also encourage the formation of “in-groups” and “out-groups,” giving rise to envy, prejudice, and possibly aggression, while it appears to enhance bonding and the formation of communities.

Having obtained oxytocin, participants in a 2014 study were more likely to lie in the same group for the benefit of others. The findings could help “providing insight into when and why collaboration turns into corruption,” the researchers said.

More work is required to understand oxytocin’s nature, and what it does.

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