You’ve matched on Tinder, and now you’re about to meet for the first time. There are butterflies in your stomach, and your heart begins to race. Is the date going to go well? What’s going to happen next?

In other words, love can be intimidating. But what exactly happens to your brain and body when you’re falling in love?

According to Dr. Helen Fisher, a researcher at Rutgers University specializing in love, there are three stages of romantic love: lust, attraction and attachment. Her study was last revised in 1997, but it’s still referenced today.

Lust, or sexual desire, involves the chemicals testosterone and estrogen in both males and females. The hypothalamus is most active during this stage of love by releasing phenylethylamine, which then triggers the release of testosterone. Although testosterone has a more significant impact on sex drive, females’ sexual desire tends to increase during ovulation because of higher estrogen levels.

Dopamine and norepinephrine are the chemicals active during the attraction phase. Dopamine is commonly referred to as the “feel good chemical.” In fact, while you’re in love, your brain looks like the brain of someone on cocaine, according to ASAPScience. Love (and cocaine) fires up the reward system in your brain.

Along with epinephrine, norepinephrine is part of the “fight or flight” response. Norepinephrine is responsible for your racing heart when you see your bae. While dopamine and norepinephrine amounts increase, serotonin levels fall. Low serotonin levels are a sign of OCD, so this explains why we constantly think about the other person when we first fall in love.

A similar chemical response happens when we kiss. Serotonin decreases while dopamine and oxytocin increase. Additionally, cortisol, a hormone related to stress, decreases while kissing.  Why does kissing feel so good? Putting aside the rush of chemicals released, your lips are one of the most sensitive parts of your body. Because of the many, many nerve endings, kissing gives you all the feels.

Oxytocin levels also rise during the attachment phase of love, along with vasopressin. Oxytocin helps us bond with other people. During the attachment phase, levels of dopamine tend to fall. But don’t worry! Oxytocin is also known as the “cuddle hormone,” so once you find your perfect match, you can be in each other’s arms forever.

So how do you know you’ve found the right person? Psychologist Arthur Aron and other researchers performed an experiment exploring if it was possible to creating feelings of closeness and intimacy quickly. Students asked each other three sets of questions to get to know each other. Although their results did show that intimacy could be created in only 45 minutes, the researchers recognized that “it seems unlikely that the procedure produces loyalty, dependence, commitment, or other relationship aspects that might take longer to develop.”

But if you ever run out of things to talk about on a date, here are the 36 questions Aron used in his experiment. We hope they help you find love — Happy Valentine’s Day!