Love is the most mysterious of emotions, inspiring centuries of philosophy, poetry and literature. But beneath its dreamy, poetic exterior lies a complex set of interactions in the brain, where chemicals and hormones trigger the feeling that warms your heart and captivates your soul.

While we might not be able to explain it, scientists can pinpoint what’s happening in the brain when we fall in and out of love. It turns out that the chemical changes that occur when you first meet a potential lover stimulate your brain’s pleasure centers and lead to feelings of attraction, lust and obsession. These initial feelings of lust are driven by elevated levels of testosterone and estrogen, along with the neurotransmitters dopamine and norepinephrine, which cause a faster heart rate, restlessness and loss of appetite. In addition, the brain produces the oxytocin hormone, which is released during physical affection and leads to feelings of bonding, along with vasopressin, which generates the desire to protect a loved one from danger. The combination of these chemicals and sensations can produce ecstasy when things go well, and despair when they don’t. It also can trigger obsessive thinking, a craving for sex, sexual possessiveness and emotional dependence. In addition, the experience of love can trigger feelings of sacrifice and a strong desire to be with a loved one.

Once the initial feelings of lust and bonding begin to fade, the brain begins to produce different neurotransmitters that promote companionate love. These feel-good hormones, such as oxytocin and dopamine, lead to a sense of security, trust and closeness. This type of love has been found to promote a more positive and healthy relationship than passionate love. It has also been found to reduce stress, and encourages behaviors that nurture the relationship, such as empathy and generosity. This type of love is rooted in evolutionary biology, and serves to keep parents and children bonded through attachment so they can survive together.

However, it’s important to remember that loving someone is not just a feeling, but a choice. When you stand in love, you are taking action by enacting loving values and standards, such as empathy, respect, vulnerability, honesty and, according to Velleman, celebrating a person for who they truly are. This kind of love can help you live a longer, healthier life by reducing your stress levels, boosting your immune system and improving sleep quality.

Love extends beyond romantic relationships, and is triggered by many other types of relationships. Spending time with family members, friends and pets, as well as engaging in activities you enjoy, will all activate the same love pathways in the brain as falling in love. Ultimately, it’s important to have different experiences of love, as all forms can contribute to a long, happy and healthy life.