The molecular formula C9H13NO3 may refer to: Epinephrine ·
Epinephrine, also known as adrenalin or adrenaline, is a hormone, neurotransmitter and medication. Epinephrine is normally produced by both the adrenal glands and certain neurons.

Dopamine: increased energy, less need for sleep or food, focused attention and exquisite delight in smallest details of this novel relationship”.   

Chemistry of love
The receptors are located in the same place as the reaction of euphoria when taking a drug. This causes people to become addicted to love.