One of the most common sex myths centers on casual sex, and how “dangerous” educators believe it to be. From an educational standpoint, it is typical for teachers to denounce casual sex by quoting research on hormones and neurotransmitters, particularly ones like oxytocin and vasopressin, which promote bonding and connection. However, while there is truth in the role of brain chemistry during sex, these ideas are often manipulated as fear-based tactics more than anything else.
There are several key hormones and neurotransmitters at play during any sexual encounter, including oxytocin, vasopressin, dopamine, and prolactin. Here is a very short overview of each:
Oxytocin has been coined “the love hormone,” as it is heavily present in relationships and helps build emotions such as connection and trust. Women produce larger amounts of oxytocin than men do until around midlife, when the percentages are more aligned.
Vasopressin, similarly to oxytocin, is involved in generating feelings of attachment and love (2).
Dopamine plays a huge role in the pleasure and reward center of the brain.
Prolactin, which spikes after an orgasm, helps bring someone back to base level. For example, it helps reduce those same high levels of dopamine.
Now let’s break down how these all interact during our sexual experiences.
Sexual Activity and Orgasms
Bodies release oxytocin in moments of physical contact, such as a touch of the knee or arm, or kissing. Both oxytocin and dopamine build up the longer an encounter such as foreplay lasts, and bodies then add vasopressin into the mix, Matthais Roberts explains in Beyond Shame: Creating a Healthy Sex Life on Your Own Terms.
During an orgasm, there is a strong peak of oxytocin and vasopressin, and dopamine levels increase by up to 400 percent. Post-orgasm, those feelings can stay around for about five minutes before prolactin begins to set in and actively lowers the amount of dopamine in the brain, bringing you back down from the initial high. Both prolactin and dopamine eventually dissolve as your system returns to normal, while oxytocin and vasopressin remain and can build emotional connections over time.
Are You Going to Get Attached?
At first glance, it might seem like sex will automatically leave you with feelings for a sexual partner. However, there are several important things to learn here.
1. While oxytocin and vasopressin are attachment and connection hormones, it’s more helpful to think of them as contributing to feelings that build over time (1). And while plenty of people tend to warn about the hormonal pitfalls of casual sex, these conversations tend to focus on women, given that they have elevated levels of oxytocin for most of their lives.
… but what those same people tend to forget is the existence of the orgasm gap, which also contributes to how many people produce the feel-good hormones to begin with..
2. Because, remember: dopamine levels rise up to 400 percent during orgasm — and there is a big difference between having sex and reaching orgasm. And as fun as casual sex can be, plenty of people are typically not even having orgasms in these encounters. Hookup culture studies have shown that close to 90 percent of women go without an orgasm after a one-night stand. Surprisingly, so do about 40 percent of men — which means that a majority of people aren’t getting the full blast of the would-be attachment hormones.
Don’t Women Get More Depressed?
It is worth mentioning that researchers have found that while men report few experiences of post-sex depression, it can be common for women to have depressive symptoms from casual sex (4). However, we need to question, is this because of the hormones and neurotransmitters? Or is this due to societal experiences?
Sex norms for women and men are incredibly different. Women experience everything from slut-shaming, to degrading comments, to a hyper-awareness on looks and body image from many angles such as social experiences, porn, and media. “Sex is largely a learned response… what is learned is furnished by the society in which we grew up,” sexologist Lou Paget explains in Orgasms: How to Have Them, Give Them, and Keep Them Coming.
Destigmatizing female sexuality and supporting sexual exploration are key in undoing some of these stressors and ills. This would be much more beneficial than inciting fear tactics or insisting that girls always need to say “no” to new experiences.
Can You Have Casual Sex?
These findings suggest that “friends with benefits” has the potential to end with someone “catching feelings.” And while you’ve likely been cautioned against those types of relationships, the science above is a good indicator of why. Therefore, it is something worth keeping in mind — but again, not a good enough reason to restrict yourself from engaging in the consensual sexual experiences that you desire.
Ultimately, your hormones and neurotransmitters are not going to have as large of an effect on you as some educators like to insist. Sure, you’ll likely experience feelings of closeness during sex, particularly if it’s sex with a long-term partner. However, it’s more important to empower people to make decisions that are both consensual and feel best to them.
- Roberts, Matthias. Beyond Shame: Creating a Healthy Sex Life on Your Own Terms. Fortress Press, 2020.
- Carter, C. Sue. "The oxytocin–vasopressin pathway in the context of love and fear." Frontiers in endocrinology 8 (2017): 356.
- Paget, Lou. Orgasms: How to Have Them, Give Them, and Keep Them Coming. Broadway Books, 2005.