How the Chemistry of Kissing Helps your Love Life

Kisses are a major part of today’s romantic relationships. From the butterflies of anticipating the first kiss with a new beau to the relief of a welcome-home-from-work kiss with a lifelong partner, the effect of kisses on our emotions is obvious to us. However, we may not be aware of the chemistry of the kisses we are sharing, and how this chemistry is so important for finding “the one,” and keeping them long term.

Anthropological research has shown that 90% of the world’s cultures today include kissing as a part of romantic interactions (Kirshenbaum, 2011). Depictions of lovers kissing have been found in ancient Egyption art and ancient Hindu Veda Sanskrit texts, some of the oldest artifacts we have of Earth’s cultures long-gone (Parkinson, 1999). When a human behavior is found across cultures and time, this is sometimes a clue that there may be a biological function to the behavior.

The Chemistry of the First Kiss

Let’s start with those exciting first kisses. While there are people and subcultures today who choose to save their first kisses for marriage, other people and subcultures share their first kisses during the “evaluation” process of dating or courting. Research has shown that those first kisses may provide important chemical information to each kisser’s brain. Being so close to each other’s faces allows for the senses to detect pheromones like androstenone and androstenol, which offer information about the partner’s health and genetic fitness (Thorne, et al., 2002; Thornhill & Gangestad, 1999). Because a woman’s scent and pheromones change along the course of her menstrual cycle, information would also be offered about her fertility in the moment (Thornhill, et al., 2003). 

Although you’re not actively thinking to yourself “Huh, I’m noticing Jimmie’s pheromone profile isn’t so great” as you kiss Jimmie, the information is being processed by the deeper, more animalistic parts of your brain, subconsciously. Because of this, first kisses can often change people’s attraction to each other, whether positively or negatively (Wlodaski & Dunbar, 2013). The chemical information provided by first kisses is most influential to the brains of people who want to be more selective with their partners (Wlodaski & Dunbar, 2013). The people who approach a new potential partner with choosiness are more swayed by the initial kisses, one way or the other, while the people who have lower standards are less swayed, one way or the other. When a kiss with a certain person feels surprisingly satisfying (or not so satisfying), it might just be that this subconsciously processed information has emerged to your consciousness as an “inexplicable” state of satisfaction. 

The Chemistry of the Long Term Kisses

Now, the process is different for the kisses of long term partners. By now, they have already chosen each other and their subconsciouses would already be aware of the other’s genetic profile. Information about the female partner’s fertility would still be useful during long term relationships, but now there are maintenance needs also at play. The goal is no longer to evaluate your partner, but to keep them and keep love present.

As such, it makes sense that the chemicals involved in emotional bonding would be aroused by kissing. This is exactly what the research has found (Esch & Stefano, 2005; Light et al., 2005; Macdonald & Macdonald, 2010). Kissing a romantic partner has been shown to release natural opiods and neurohormones in the brain. The most important of these is oxytocin, which is elicited when kissing, and helps create feelings of affection, love and commitment. What does it mean that kissing your long term partner creates a surge of oxytocin in your brain? It means that you’ll want to kiss more often and that you’ll enjoy it more when you do (Wlodarski & Dunbar, 2013). This effect is so strong that the frequency of kissing between long term partners statistically predicts their relationship quality, while even the frequency of sex between them does not have this predictive power (Wlodarski & Dunbar, 2013). Isn’t that fascinating? How often a long term couple kisses is more strongly related to their romantic wellbeing than how often they have even deeper forms of physical intimacy like sex.

It’s interesting to note that the meaning and chemistry of kisses varies depending on the type of partner you are. If you’re someone who desires short term relationships and flings, then the chemistry of kisses at the initial stages of a relationship will affect your brain more strongly. You’ll be more likely to be swayed one way or the other by the chemistry you encounter during a first kiss, and less so by the later “maintenance” kisses. On the other hand, if you’re someone who desires long term relationships and commitment, then the chemistry of kisses at the later stages of a relationship will affect your brain more strongly. You’ll be less likely to be swayed by the first kiss, and the effect of oxytocin from the maintenance kisses will have a stronger effect on you (Wlodarski & Dunbar, 2013). 

With all this said, maybe it’s time to go kiss your partner.



Esch, T., & Stefano, G. B. (2005). The neurobiology of love. Neuroendocrinology Letters, 26, 175–192.

Kirshenbaum, S. (2011). The science of kissing: What our lips are telling us. New York: Grand Central Publishing.

Light, K. C., Grewen, K. M., & Amico, J. A. (2005). More frequent partner hugs and higher oxytocin levels are linked to lower blood pressure and heart rate in premenopausal women. Biological Psychology, 69, 5–21.

Macdonald, K., & Macdonald, T. M. (2010). The peptide that binds: A systematic review of oxytocin and its prosocial effects in humans. Harvard Review of Psychiatry, 18, 1–21.

Parkinson, R. B. (1999). The tale of Sinuhe and other ancient Egyptian poems, 1940-1640 BC. New York: Oxford University Press.

Thorne, F., Neave, N., Scholey, A., Moss, M., & Fink, B. (2002). Effects of putative male pheromones on female ratings of male attractiveness: Influence of oral contraceptives and the menstrual cycle. Neuroendocrinology Letters, 23, 291–297.

Thornhill, R., & Gangestad, S. W. (1999). The scent of symmetry: A human sex pheromone that signals fitness? Evolution and Human Behavior, 20, 175–201.

Thornhill, R., Gangestad, S. W., Miller, R. D., Scheyd, G. J., McCollough, J. K., & Franklin, M. (2003). Major histocompatibility complex genes, symmetry, and body scent attractiveness in men and women. Behavioral Ecology, 14, 668–678.

Wlodarski, R., Dunbar, R.I.M. Examining the Possible Functions of Kissing in Romantic Relationships. Arch Sex Behav 42, 1415–1423 (2013).



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