Love or Infatuation? The Practical, Time-Based Test
Infatuation and love can feel like the exact same thing from inside your own head — the racing thoughts, the phone checked every few minutes, the conviction that this person is different from everyone who came before them. They are not the same thing in a lab. Marazziti, Akiskal, Rossi & Cassano (1999) measured a serotonin-related marker in blood platelets across three groups of 20 people each — recently in love, diagnosed with obsessive-compulsive disorder, and neither — and found the levels in both the newly-in-love group and the OCD group significantly lower than in the controls.
That doesn't mean you have a disorder — it means the feeling you're using as evidence is, on its own, useless as evidence. Early chemistry and early obsession share a signature, and only one of them is love. What separates them isn't intensity. It's whether the feeling is still standing after the intensity leaves.
Write down what you actually notice about them — the version worth keeping survives the retelling.Because the overlap isn't a coincidence — it's the same neurochemical system running the same program. Marazziti's team wasn't reaching for a metaphor when they compared new lovers to OCD patients; they were testing a real hypothesis, that an "overvalued idea" (a person you can't stop returning to) and an obsession (a thought you can't stop returning to) might share machinery at the level of the serotonin transporter. The data said yes.
What that finding doesn't tell you, on its own, is how long the overlap lasts — which is the actual question if you're trying to read what you're feeling right now, not what you felt in week one. A later review of this body of research answered it: serotonin-transporter levels, along with a cluster of related markers tracked across the same studies, do not differ from controls 12–24 months after initial measurement, Bode & Kushnick (2021). The chemistry of the first months doesn't hold at that level for long; whatever you're feeling a year or two in is running on something else.
Not everything fades. Acevedo, Aron, Fisher & Brown (2012) scanned the brains of 17 people, ten women and seven men, married an average of 21.4 years, and found the same dopamine-rich reward regions active that light up in brand-new lovers — just "generally without the obsession component common in the early-stages of relationships." The reward stays. The obsession is what's supposed to leave.
This is the part that gets lost whenever "it's just infatuation" gets used as a debunking, as if real love should feel calmer, quieter, less like a chemical event happening to you. The sample was 10 women and 7 men, scanned while looking at photos of their spouse — decades in, and the reward system still fired. So the honest version isn't "infatuation fades and love feels calm." It's closer to this: the reward stays, and the compulsive checking, the catastrophizing over a slow reply, the inability to think about anything else for weeks at a stretch — that part is supposed to leave. If it hasn't left after two years, that isn't devotion. It's a longer obsession.
Every one of those markers is partly triggered by what someone looks like — a new face is part of what fires the reward system in the first place. Strip the face out and read only what a person actually wrote, and whatever spark survives has to come from vocabulary and voice instead. That's the accidental experiment Anketta runs on every new match: no photos before you've already spent time reading someone in full, so whatever infatuation takes hold there is at minimum missing one of its usual triggers.
"If it's love, these initial feelings may lessen, too. But the neurotransmitters tied to attachment will kick in and what will emerge is a desire to bond, to want to be close, and to share life experiences." — Abigail Brenner, M.D., psychiatrist, Psychology Today (2021)
You can't biopsy your own platelets, and you shouldn't wait two years to decide whether someone is actually serious about you. What you can do is track the same kind of markers researchers track, on a faster and smaller scale:
- Note the actual date, not the vague feeling. Write down when the intensity started. You need a fixed point to measure against later — memory will round it up to "always."
- Watch what happens on a boring day. A cancelled plan, a late reply, an ordinary Tuesday with nothing happening — infatuation dims a little under boredom. Whether the interest survives a dull afternoon says more than how it survives a good one.
- Check whether your other attention comes back. Early obsession crowds out friends, work, sleep. If two months in you still can't hold a normal conversation about anything else, that's the OCD-adjacent signature talking, not depth of feeling.
- Notice flaws without the feeling collapsing. Idealizing someone is part of the early package. Love is what's left once you've noticed something genuinely annoying and stayed anyway.
- Give it the interval the research gives it. Somewhere in that 12-to-24-month window, the obsessive layer is supposed to thin out on its own. Whatever is left underneath at that point is your actual answer.
Often, yes — the two aren't opposites so much as stages that sometimes hand off to each other and sometimes don't. The table below is the difference as the research actually draws it, not as a vibe:
| Infatuation | Settled love | |
|---|---|---|
| What's active | Reward system + serotonin-transporter changes resembling OCD | Same reward system, without the OCD-like overlap |
| Typical duration | Markers back to control levels within roughly 12–24 months | No fixed endpoint studied; the 21.4-year-married sample still showed reward activity |
| What a bad day does to it | Dents it hard — a boring stretch or a slow reply can read as a crisis | Barely touches it — annoyance and affection sit side by side |
| What keeps it going | Novelty, uncertainty, frequent contact | Ordinary contact; tolerates real distance and real silence |
Some of what people reach for instead of this test — a compatibility quiz, a personality score, a friend's confident read on your situation — is a genuine shortcut, and none of it replaces the interval. A quiz can flag two people likely to get along. It cannot tell you, in week three, which chemical is currently running your judgment. Only the calendar can do that.
Keep living like it might be either one, because right now it genuinely is — the two conditions look identical from month one, and only time tells them apart. Don't let the first few weeks decide anything expensive to reverse: a lease, a move, a family introduction framed as permanent.
Do:
- Keep other relationships and commitments intact instead of clearing your calendar for one person
- Let the relationship survive ordinary logistics — a busy week, a missed call — before reading anything into how it held up
- Put what you actually think in writing rather than performing calm out loud; it's easier to be honest on a page than out loud, which is most of the point of writing before meeting in the first place
Don't:
- Make a decision that's expensive to reverse — moving in together, meeting the family as "the one," relocating for them — before the interval has run
- Treat the absence of doubt as proof; the OCD-adjacent phase runs on certainty, not on evidence
- Confuse how rarely you think about anything else with how much you actually know about them
If two years in the answer turns out to be no, the research on this next part is at least clean: ending things directly costs both people less than a slow fade, whichever chemical got you there in the first place.
How long does infatuation usually last before it fades?
Research on serotonin-transporter changes in people newly in love found the markers no different from controls 12 to 24 months after the first measurement. That's a population average, not a deadline for any one person.
Can you feel "in love" and have it still be infatuation?
Yes — the feeling itself doesn't distinguish the two conditions. The neurochemistry researchers can measure does, and you don't have lab access. Time is the closest substitute you have.
Does how intense it feels predict whether it's real?
No. Intensity is the overlap, not the tell — it's exactly what early love and clinical obsession share. What predicts durability is whether the feeling holds up once the intensity fades.
Is it normal to think about someone constantly in the first few weeks?
Yes, and it's also exactly the pattern the OCD comparison describes. Normal and diagnostic-looking aren't opposites in month one — they're the same thing, seen from two different rooms.
What usually survives once the early rush is gone?
The reward-system response itself, going by couples studied decades into a marriage — just without the compulsive checking, catastrophizing, and tunnel vision that came bundled with it originally.
Should you make big decisions during the infatuation phase?
Not the expensive, hard-to-reverse ones. Wait for the interval the research describes to pass, then decide with whatever's left once the urgency has worn off.
Nobody gets a lab result on their own relationship. What they get, if they wait, is a quieter version of the same feeling — or nothing where the feeling used to be.
Unsure about writing? Try reading first.