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Why we fall in love - The main reasons why we fall in love come from our ancestors. The need for pair bonding and reproduction were essential for the evolution of our species.

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Enter the science of love - Nature took care of ensuring we didn't go extinct by managing our hormonal responses in a way that allowed us to survive as a species.

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Three stages of falling in love -

When we fall in love, we go through three stages: lust, attraction, and attachment. All three stages are associated with different hormonal responses.

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Lust - This is our limbic system working at its best. It's the initial sexual attraction we feel towards a person we find attractive.  

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Lust - Estrogen and testosterone are the main hormones responsible for this feeling.

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Lust: norepinephrine - Norepinephrine, or PEA, is a naturally occurring amphetamine that increases the experience of joy and reduces appetite. It's usually released on this stage and continues into the attraction phase.

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Attraction - This is where all the fun begins. This stage happens after the first biological response and it triggers a number of hormonal responses.

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Reward system - Love essentially triggers a feedback loop in our brain's reward system, making us want more. It kicks in mostly during this phase.

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Attraction: adrenaline - Yes, the first rush comes from adrenaline. Falling in love with a person will actually cause a stress response in your body.

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Attraction: adrenaline - It's likely that you have experienced these symptoms. Think a racing heartbeat, dry mouth, or sweaty palms. These are all reactions triggered by adrenaline.

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Attraction: dopamine - Being in love induces our bodies to produce the neurotransmitter dopamine. Also known as the "feel good" hormone. Dopamine is responsible for feelings of pleasure and happiness.

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Attraction: dopamine - Dopamine is a natural "high." Its stimulant effects on the brain can make you feel great!

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Attraction: dopamine - Effects of high dopamine levels include increased energy, increased focus, and feeling less hungry. 

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Attraction: serotonin - Can't stop thinking about your newfound love? That's serotonin in action!

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Attraction: serotonin - Women tend to produce slightly higher levels of serotonin than men when falling in love. 

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Attachment: oxytocin - This is the hormone that makes us want to cuddle. It's responsible for feelings of attachment with our loved ones. 

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Attachment: oxytocin - There is a spike in oxytocin levels during  o r g a s m.

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Attachment: oxytocin - Oxytocin is also the hormone that makes us bond as humans. It's key in the relationship between mother and child immediately after birth.

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Attachment: oxytocin - So much so that it mediates lactation. It essentially signals the breasts to release milk when the baby needs it.

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Attachment: vasopressin - Vasopressin is mostly known as an anti-diuretic. It works in the kidneys and it controls thirst.

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Attachment: vasopressin - This hormone is also released immediately after sex. This hormone plays a key role in sex and partner preference.

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Attachment: vasopressin - Vasopressin is an essential hormone that promotes healthy, long-lasting relationships.

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Love hurts - As with many other addictions, going cold turkey can be painful.

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Love hurts - We feel withdrawal symptoms when we break-up with our partner.

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Love hurts - Dopamine controls most of the brain's reward system, so it's natural that a crash in dopamine release will make us feel like we have a broken heart.

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When the cocktail goes wrong - Unbalanced hormonal levels can lead to a series of issues, particularly because our brain's reward system is involved.

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When the cocktail goes wrong - Excessive levels of dopamine can play a role in addiction. The same areas of the brain can be triggered by drugs or by binge eating for instance.

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When the cocktail goes wrong - Too much dopamine and the reward pathways in our brain can start seeking for excitement elsewhere. Addiction, jealousy, and erratic behavior can be a result of us trying to get the next dopamine "fix."

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Love -

Love is a complex chemical cocktail that is an essential part of the human experience. Enjoy it!

See also: Why more couples are choosing not to live together 

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