What's the difference between love and lust?

Different systems, different timelines.

Helen Fisher’s research describes three overlapping but distinct systems: lust (driven by testosterone and estrogen, aimed at almost anyone who fits your general “type”), attraction (the dopamine-fueled infatuation that narrows focus to one specific person), and attachment (oxytocin and vasopressin, the slower system that builds long-term bonds).

Lust can exist without attraction or attachment ever kicking in. Attraction can flare up fast and fade in weeks if the attachment system never activates. What most people mean by “real love” is that third system: the one still running after the intensity of the first two has worn off.

The practical test: does the pull remain when the urgency doesn’t? Lust wants someone. Attachment wants this someone, specifically, even on the days when wanting isn’t urgent at all.