One problem with both the dopamine and the endorphin explanations is that assume that happiness is the same as pleasure

While it’s certainly possible (normal, even) to be happy while experiencing pleasure, to be truly happy surely requires a lot more than that

Life is more
than just a series of euphoric moments

Happiness
is also about contentment, satisfaction,
love,
relationships, family, motivation, wellbeing, and
many other words found in Facebook memes.

Could there be a chemical that supports this more
«profound» stuff? Maybe

One contender would be Oxytocin

Oxytocin
has an unusual reputation, often being described
as the love* hormone, or the cuddle hormone.
Despite what much of the modern media would
suggest, humans are a very friendly species, and
usually actively need social bonds with others in
order to be happy. The closer and more intense
these bonds, the more important they are. The
bonds between lovers,
relatives, very close friends, tend to make people happy over the long term. And oxytocin is apparently integral for
these