If Love is Caused by Hormones...is it Real then???

As a teenager thinking deeply (as I considered it back then) about philosophical topics, this question struck me as significant: "If love is caused by hormones...is love real then?" My intellectual answer back then was no, but over the years I got an intuitive understanding that something being "caused by hormones" doesn't make it less of a thing. Maybe you never thought about this question, or never considered it relevant, or knew a better answer all along. However, I found it troubling back then!
And it took me many more years (without actively searching for an answer) and to accidentally stumble upon ideas from philosophy of science to finally make coherent sense of the question and give a satisfying answer.

In (psychological) scientific analysis you can look at a phenomenon (anything from addiction over memory or happiness to love) on various levels of analysis. You could start at atomic or even subatomic level to understand the matter things are made of (but usually that's not relevant for psychological phenomena). You can look at molecules and macromolecules (proteins, hormones...) or at cells and neurons, you can ask how different neurons or cells interact in a certain phenomenon (systemic level) or you go directly on the behavioral level of the individual or the inter-individual or social level. It of course goes further "up" (community, culture, anthropological...). 
So, something can correlate with a certain release of hormones on the molecular/cellular/systemic level AND also have behaviour by a person on the whole organism/individual level. One thing is not one thing or the other, the scientific question determines whether the answer is "the release of oxytocin increases" or "Alice spends more time around Bob". It's not "either...or", it can be both.
Which level "causes" the effect on another level is a whole different question and the causality between different levels is not always from "lower to higher" or always from "higher to lower", depending on the phenomenon it can be the one or the other or it can be both. For example if you are constantly thinking negative thoughts your hormones might also change, while injecting hormones can also change your thinking.
So "one level is not more true than another level" and "causality is not straight-forward either".

Then there is this "easy" topic of your subjective experience. This thing, also called consciousness, phenomenology, Dasein or many other words is basically inaccessible to anyone else but you. The problem how to go from observable things to subjectivity is the "qualia problem" or "the hard problem of consciousness". While some philosophers argue this phenomenon doesn't really exist, well, just look at the screen while reading this article, focus on your body, feel it. Do you feel something? Do you feel yourself existing? Well, that's how my argument goes. 

Is love real then? The phenomena changes your behaviour as a person, can be measured in your hormones and changes your experience in the world. It is real on multiple levels, so yeah, don't worry, it's pretty damn real.

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Some philosophers argue, however, that "lower" levels are "more real" than other levels, this is called reductionism. (The term can also mean something else, as always in philosophy)