We all know how it feels when you see someone across the room.

Your eyes meet and everything slows down for a minute.

Your medial prefrontal cortex plays a big role in your initial attraction to someone.

And it judges physical attractiveness in just a milliseconds.

Does your heart flutter when you see your crush?

The adrenal gland causes the hormones adrenaline, epinephrine and norepinephrine, to be pumped through your blood.

In turn, your heart beats more quickly.

Or maybe you get butterflies in your stomach.

This happens when adrenaline is sent to your lungs, muscles, and brain.

This also directs blood flow to those areas, with not a lot of blood left for your stomach.

Dopamine is also the reason you feel so good.

Tests show that love has a similar effect on dopamine levels as taking drugs, such as cocaine.

Sometimes, we get obsessed or fixated on our new love.

Couples who have recently fallen in love have significantly lower levels of serotonin.

This is also experienced by people with Obsessive Compulsive Disorder, which may explain why you can't stop thinking about your new boo.

Falling in love can be stressful, though.

Cortisol, a stress hormone, is higher in people who have recently fallen in love.

But overtime, kissing your loved one will lower your cortisol levels.

One study even found, that being married will lengthen a man's life by seven years and a woman's by two years.