Romantic Chemistry Explained



In human chemistry, there is a chemical bond that functions to hold human molecules (people) together into bound-state entities, such as marriage pairs. These chemical bonds are responsible for feeling that special connection with someone; they are responsible for feeling that you have to see this other person again; they are responsible for "the spark." Simply put, chemistry is the emotional and psychological way two people relate to each other.


There has been numerous attempts to explain what causes this type of romantic chemistry to occur. Researchers say a combination of factors are needed, including physical attraction, similarity, non-judgement, feeling understood, mutual trust, communication, and mystery. Let's dive into each of these factors separately. 



Sexual attraction is one of the most important factors of chemistry. This can be attributed to the fact that eighty percent of what we take into the human brain is visual. “Sexual chemistry does not always equal love, and this is because we’ve evolved distinct brain systems for mating,” says Helen Fisher, Ph.D. “One system controls the craving for sexual gratification. Another system rules over romantic love – that obsessive thinking, craving, and focusing on one individual. They’re not always connected, which is why you can be madly in love with someone and only have so-so sex, while you can have intensely passionate sex with someone you never want to see again!”¹ However, sometimes one thing can trigger the other.



If you're under the impression that only opposites attract, biochemistry will tell you otherwise. According to research, we are attracted to people with similar DNA.² Thus, we are attracted to people with similar facial features, personality traits, and language styles.

When we meet others who are similar to ourselves, we feel a sense of ease and comfort to disclose information about ourselves because we believe the other person will understand us. And vice versa – we feel that we can accurately interpret their facial expressions and emotions. This ability to understand each other leads to feelings of non-judgement and mutual trust. Lastly, we seek people who are similar to ourselves because we understand that long-term compatibility is more likely with someone who shares the same traits.³ 



Communication, in all of its verbal and non-verbal forms, is a vital component to feeling chemistry. When two people experience a deep connection, communication will feel very open and you will feel as if you’ve known the other person for a long time very quickly. This can be described as being on the same wavelength; you are resonating with very similar vibrations

Everything in the universe is moving and vibrating at different frequencies. Everything has its own vibrational frequency – even our thoughts and feelings. Thoughts actually have the strongest and fastest measurable wavelength, and when we feel chemistry with someone, we will often find they have similar thoughts to ours. This is the universal law of like attracts like, a.k.a. the law of attraction. This law, which is based on the law of vibration, states that we attract what we are sending out. Hence positive energies attract positive energies and negative energies attract negative energies.

In terms of romantic chemistry, vibrations of similar frequencies are magnetized to each other. In other words, the dominant vibrational frequencies of two individuals are in resonance (two frequencies attuned to each other).

This is why when communication styles match or complement each other, and two people make similar assumptions, it’s easy to create rapport, and they rarely bump each other out of rapport. This rapport is what leads to a deep romantic chemistry.



Mystery is important in feeling romantic chemistry. You fall in love with somebody who's somewhat mysterious because mystery elevates dopamine in the brain, which pushes you over the threshold to fall in love.¹ Dopamine is critical in all sorts of brain functions, including thinking, moving, sleeping, mood, attention, and motivation, seeking and reward.

It’s all about seeking — Research shows that dopamine causes us to want, desire, search, and seek out in attempts to feel pleasure and reward. From an evolutionary stand-point this is critical: the dopamine seeking system keeps us motivated to continue learning and surviving. Dopamine makes us curious and fuels our searching for information. From a human relationship stand-point, it makes sense that mystery would increase our dopamine levels and cause us to seek out more information about this person. We are constantly intrigued and engaged by their mysterious aurora.

Unpredictable is the key — Dopamine is also stimulated by unpredictability. When something happens that is not exactly predictable, it stimulates the dopamine system. This is why we are attracted to people who might like us. When receiving clear signals of interest from another person, a person is momentarily pleased, adapts quickly, and the case is closed. But when interest is unpredictable, this leads a person to seek out an explanation, causing them to think of little else. Eventually the person interprets this arousal and stimulation as a sign of liking the other person. This is why "playing hard to get" in the initial stages of a relationship actually holds some truth.



There is one more explanation I would like to share on why chemistry occurs. Kelly Campbell, Ph.D. says, "Chemistry occurs most often between people who are down-to-earth and sincere. This is because if a person is comfortable with themselves, they are better able to express their true self to the world, which makes it easier to get to know them, even if perspectives on important matters differed."⁵ Thus, sincerity is also an important factor in romantic chemistry. You must be sincere in your actions in order to build mutual trust – the foundation for any successful relationship. 


The main takeaway is that people who are similar to one another have a much higher chance of experiencing deep, romantic chemistry. These similarities include a wide range of factors, including physical appearance, personality, communication, tone of voice, body language, and even your thoughts and feelings. The most surprising finding is the fact that our own thoughts can be the cause of chemistry with another person – we attract others with similar thoughts to ours.

A combination of these factors are needed at the right time and the right place in order to create romantic chemistry. Furthermore, it's important to note that chemistry is not the only thing needed for a relationship to last – compatibility and commitment are also necessary. For further reading on this topic, see Compatibility and Chemistry: Why You Can't Have One Without The Other.



1. Fisher, Helen, Ph.D. (2005, January 2). "Why We Love: The Nature and Chemistry of Romantic Love." Retrieved from

2. Whiteman, H. (2014, May 25). "People tend to choose partners with similar DNA, study suggests." Medical News Today. Retrieved from

3. Dovey, Dana. (2016, April 7). "Understanding Another Person's Emotion Signals Similarity, And May Make You Find Them More Attractive." Medical Daily. Retrieved from

4. Weinschenk, Susan. (2009, November 7). "100 Things You Should Know About People: #8 — Dopamine Makes You Addicted To Seeking Information." The Team W Blog. Retrieved from

5. Campbell, Kelly, Ph.D. (2011, August 21). "Relationship Chemistry: Can Science Explain Instant Connections?" Psychology Today. Retrieved from