Along with other chemicals oxytocin and endorphins, healthy amounts play a role in how happy we feel.

Source: https://vator.tv/news/2023-08-30-how-we-can-play-the-long-game-of-mental-health

Because it is released during physical contact, such as during affectionate caressing and sex between adult couples, as well as during pregnancy, birth, and lactation, oxytocin is referred to as the "love hormone."

Source: https://www.bleedinggreennation.com/2023/2/25/23614531/how-does-sexual-activity-reduce-stress-and-anxiety

In one study from 2012, 30 men who were in monogamous relationships maintained a slightly greater social distance from an attractive female stranger when they received an intranasal oxytocin spray than when they got a placebo.

Source: https://www.discovermagazine.com/mind/oxytocins-effects-arent-just-about-love

In past studies, voles given drugs that stopped oxytocin being processed no longer formed pairs, and mothers failed to produce milk for their young.

Source: https://www.ndtv.com/world-news/love-hormone-oxytocin-may-not-work-as-we-think-new-study-suggests-3730515

Their calm demeanor and the release of oxytocin (the “feel-good” hormone) during interactions assist people with bipolar disorder.

Source: https://www.healthcanal.com/mental-health/anxiety/anxiety-service-dog

The release of sleep-friendly hormones, including serotonin and oxytocin, and a reduction in hormones like cortisol.

Source: https://www.cnet.com/health/sleep/headphones-for-sleeping/

The researchers then dosed some of the mutant fish with oxytocin and found that their response changed—becoming more similar to the standard fish.

Source: https://gizmodo.com/fish-may-feel-each-others-fear-study-oxytocin-empathy-1850256156

The team said learning how the oxytocin system works in humans “may offer new ways to help human mothers who want to breastfeed but struggle to do so”.

Source: https://www.bicesteradvertiser.net/news/national/23802483.brain-mechanism-may-explain-breastfeeding-mothers-leak-milk-babies-cry/?ref=rss

Though the results don't prove a direct link, other evidence, such as the role of the oxytocin in breastfeeding, suggests a connection.

Source: https://www.zmescience.com/science/breastfeeding-challenges/

Yet regardless, oxytocin is an important chemical messenger, shown to mediate all sorts of emotional responses in humans and other mammals.

Source: https://gizmodo.com/fish-may-feel-each-others-fear-study-oxytocin-empathy-1850256156