Sexual Chemistry

When people talk about “Sexual Chemistry” they are most often referring to how two people interact and relate to one another on a sexual level, whether sparks fly when they kiss, their spines shiver at each others touch, or butterflies fill their stomachs at the thought of their next night together. There is, however, actual chemistry behind “Sexual Chemistry,” though scientists are not 100% sure exactly how our neurochemicals interact to produce the complex range of feelings and sensations associated with human sexuality. They are sure that it is neurochemical actions in our brains that give us all of these happy, excited, sexy feelings. What causes sexual attraction, the neurochemicals that light our sexual fires, and what exactly is going on in our brain during sex.

Sexual Attraction


Testosterone is the star of the show when it comes to human sexual desire and sex drive.

Most people associate testosterone with men; however, in both sexes, it is linked to increased reproduction motivation. The testosterone flowing through our bodies is what makes us take that walk across the bar to strike up a conversation in the hopes of waking up in a bed that’s not our own.

Studies have shown that testosterone production responds to chemical signals we receive from potential mates. Increased testosterone levels in our blood indicate we perceive the person we are interacting with would be a good candidate with which to reproduce. The types of relationships we are in also seem to correlate with our testosterone levels. Both men and women in polyamorous relationships tend to have higher testosterone levels than men and women who single or are in single partner relationships.

Pheromones and Smell

Have you ever taken a whiff of someone and been immediately aroused, or taken a moment to linger in a hug because you so enjoyed the other person’s natural scent? If so, it may have been your body reacting to their pheromones you were smelling.

A pheromone is a chemical produced by the body with the intent of altering the behavior of others of the same species. Depending on who or what is producing them, they can signal anything from the presence of food, raising an alarm, marking territory, to sexual health and receptiveness.

Obviously, this article is most interested in the last part, human sex pheromones. It is believed that pheromones are how we signal to potential mates, letting them know our genetic makeup, our health, and even our readiness for sexual reproduction. The science behind sex pheromones in humans is still up for debate as to exactly what chemicals are responsible for what. However, studies have shown women are more sexually attracted to the scent of men whose genetic makeup would best combine with their own to produce a stronger immune system in their potential children, and men are more attracted to the scent of women who are ovulating. So even though the exact markers are yet to be determined, it appears we are able to attract and find mates with a simple sniff of the nose.

The Neurochemical Players

A neurochemical is a molecule produced by the body to aid in neural activity and brain function. There are many neurochemicals in our brains, helping regulate everything from how much blood is flowing through our veins to how we store and process memories. Many neurochemicals perform more than one function within the brain, and can have an effect on many different systems in our body. The neurochemicals below are those that among their other tasks play major roles in human sexuality, sexual function, and the sexual experience itself.


Dopamine in the brain helps modulate our moods, but more importantly, it plays a role in positive reinforcement of behaviors that are good for our survival. It also acts as part of our brain’s reward system for doing things that are pleasurable. This chemical is released when we eat chocolate, consume caffeine, or have sex and is part of what makes these things so pleasurable to us. Dopamine is also linked with sexual arousal; its release during arousal is anticipatory of a larger flood to come with climax.


Oxytocin is sometimes called the ‘Love’ hormone. This is because it is associated with effects on bonding in both a social and sexual sense, sexual reproduction, and feelings of affection. If you have ever started seeing someone and experienced New Relationship Energy (NRE) with it’s feelings of love or fondness, constant thoughts of them, and overall preoccupation with your new partner, this is one of the hormones that was at work. Oxytocin production can be amplified by touch, and studies have found that after sex or extended periods of cuddling, blood levels of oxytocin are spiked.


Serotonin is a key player in regulating our moods and is generally associated with feelings of achievement, empowerment, and overall well being. Imbalances of serotonin have been linked to anxiety, depression, and sexual dysfunction. Research on serotonin has shown that when levels in our brain increase we become more empathetic, feel closer to those around us, and find ourselves feeling calm and satisfied. Excess levels of serotonin, however, have been linked to a decline in sexual energy and interest in sex.


Norepinephrine, also called noradrenaline, is one of our bodies “fight or flight chemicals” intended to wake us up and prepare us to save ourselves in dangerous situations. Norepinephrine released by our brain increases our heart rate and blood pressure, primes our muscles for activity, and stimulates many parts of our brain. Our body also produces this chemical to increase concentration and presence in the moment. It has the effect of narrowing focus, arousing our consciousness, body, and senses, as well as delivering a feeling of excitement and exhilaration. Increased levels of norepinephrine in the brain have been linked to feelings of joy as well as a diminished appetite, which are both symptoms people deep in the throes of an exciting new relationship have been known to report. Norepinephrine is the chemical that gets your heart racing and the butterflies in your stomach flapping at the sight of your newest crush.


Endorphin is the contracted name for “endogenous morphine,” referring to morphine like substances produced inside our own bodies. Endorphins are usually released in response to pain, but can be generated through other means as well, such as vigorous exercise or laughter. Their main purpose is to reduce pain signaling in our brain, however, they also can give us the warm fuzzies, producing a feeling of relaxation and euphoria.

Phenyl ethylamine

Phenyl ethylamine is a releasing agent for both norepinephrine and dopamine. It is released during the first stages of our attraction to another person. While high levels of phenyl ethylamine in the blood is exciting and energizing all by itself, its main function is to release other chemicals resulting in a stronger neurochemical reaction.

The Brain is our Largest Sex Organ

The Limbic System

The Limbic system is the name for a set of complex structures that are present on both sides of the brain. Some of its main parts include the hypothalamus, the hippocampus, and the amygdala. The Limbic system is sometimes referred to as the pleasure center of our brain because many of the components that make it up are key in the function of our neurochemical reward system. Much of our motivation, social interactions, behavior, and emotions are controlled in this part of the brain.

The Nucleus Accumbens

The nucleus accumbens is another major part of our brain's reward system. This part of our brain helps reinforce positive behavior and is highly sensitive to the effects of dopamine. This sensitivity is very apparent during orgasm.

The Brain During Sex


As we begin touching, kissing and caressing, our limbic system begins to light up. As you may remember one of the main functions of this area of our brain is regulating emotions. This may be why some people describe being swept up in the moment, the sexual energy carrying them forward, propelled by lust and a longing to connect with their partner. As our kissing and caressing progresses into something more, our excitement grows, our heart rate increases, and our attention narrows to what is happening in the present moment. All of which are possibly spurred on by the increased production of norepinephrine in our brain.


At this point your breath is heavy, your heart pumps fast, and your brain produces endorphins in response to your physical exertion. As we finally reach orgasm, all the parts of the brain we have been activating go off like fireworks. The nucleus accumbens comes alive giving us a rush of dopamine, causing toe curling feelings of ecstasy to wash over us. Along with this rush of dopamine comes a release of oxytocin, making us feel a connection with our partner in that moment of bliss.

Post Orgasm- Refractory Period

The refractory period is the cooling off period after orgasm. Our bodies are sweaty, limbs intertwined, chests heaving with each breath. It is at this moment our brains are basking in the warm glow of the oxytocin, dopamine, and endorphins we have just produced, enjoying the warm embrace of our partner. The large amount of oxytocin that is released during climax along with another neurotransmitter, prolactin (which is responsible for repressing dopamine’s action in the brain), are believed to be responsible for most men's inability to maintain an erection after orgasm. An increase of prolactin in our brain helps us get rid of all that extra dopamine we have just released causing a calming effect. This accounts for the stereotypical after-sex sleepiness.

The Brain is our Largest Sex Organ

Better Sex Through Science

Many people describe sex as a sharing of energies, spirits intertwining, a bringing together of two parts to make a whole. Our brain sheds light onto another way of looking at sex - sensuous chain reaction of chemicals interplaying between you and your partner. Each delicious sensation building upon the last until reaching the pinnacle of chemical bliss. Showing that with a little understanding of what is going on in your body you can add all the right ingredients to the mix to get the sizzle you are looking for between the sheets. Having a solid understanding of the way your partner’s body works can help in laying a foundation to build upon to being a better lover. It is my hope that with the knowledge contained in this article and a little practice it may just turn out you can be the “sexual scientist” that concocts the sex life of your dreams.

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