Unrequited love would be much easier to deal with if scientists would just figure out how to make a damn love potion. Romantics from opera’s Gaetano Donizetti to Ron Weasley have dreamed up elixirs that would give the lover infallible charm or the love-target tunnel vision, so humans are clearly not lacking in inspiration. Given all that biochemists have learned about the neurochemical basis for love, how hard can it really be?

The short answer: Hard AF. Scientists can pinpoint what chemicals are at work in the body when we’re in love, much like a meteorologist pointing at patterns on a screen. But like the folks on TV, they have barely an inkling of how to manipulate them for our own sad, thirsty means. And even if they could, even the smallest dosage error could lead to opposing and disastrous effects.

1. Love is a three-step process

If a love potion aims to simulate love as it takes place in the brain, it’ll have to work in stages. Biologists studying the neurochemistry of love, largely led by the work of Rutgers University scientist Helen Fisher, Ph.D., break it down into a three-step process: First comes lust, then comes attraction, and lastly, attachment — if you make it that far. Each step comes with its own palette of hormones and neurotransmitters, none of which are particularly easy to manipulate.

2. Lust chemicals hang in the balance

In 2013, a team of Oxford University scientists investigating the ethics of an anti-love potion detailed the chemical basis for lust, giving love potion hopefuls some optimism: “The lust system (libido or sex drive), for example, is distinguished by craving for sexual gratification and is largely associated with the hormones estrogen and testosterone,” they wrote in the American Journal of Bioethics. We’ve seen this in action: It’s well known that estrogen levels naturally fluctuate in females, leading to spikes in horniness at more fertile times of the month, and though it’s less clear if males have a similar cycle, flagging the sex drive in men is often treated with testosterone.

But manipulating the levels of these hormones is difficult. Both estrogen and testosterone are present in males and females at different levels, and it seems that neither hormone has a linear relationship with horniness: Too much testosterone and too much estrogen can cause a decrease in the sex drive. Given evidence that testosterone treatment can help women increase their libido, it appears that the two (in conjunction with other hormones) must exist in a delicate balance to induce peak lust. Yet scientists have yet to figure out how not to tip the scales.

Spoiler alert: In Donizetti's famous opera about a love potion, the elixir is really just booze. 

3. Attraction is addiction

When we talk about “falling in love,” we’re really just talking about the attraction phase. According to the Oxford scientists, the major brain chemical at play during this phase — sometimes referred to as “romantic love” — is dopamine. This neurotransmitter is what the brain’s reward system spits out in response to certain stimuli, like hard drugs, good food, and winning, and the happy feeling that ensues is what teaches us to crave those stimuli. Scientists think that, in the attraction phase, the brain views the object of its affection as a particularly strong dopamine-inducing stimulus — and falls head over heels trying to get its fix.

In theory, artificially inducing a dopamine surge in the brains of lovers every time they met would cause them to become addicted to each other. But that’s easier said than done: As studies about cocaine and amphetamine addiction have shown us, artificially increasing the amount of dopamine in our brains can be dangerous because humans are really bad at resisting temptation, even when they know it’s bad for them. Take a University of Geneva experiment as a cautionary tale. Electrodes were inserted in mouse brains to release an endless stream of dopamine, but the experiment went awry: “If after two hours we didn’t take them out of the cage, they wouldn’t eat, they wouldn’t drink, [and] then they’d probably die quickly, but very happily,” neurologist Christian Lüscher, Ph.D., who led the study, told Science Nordic in 2016.

4. Attraction is also stress

In addition to the insatiable desire to see your lover, the attraction phase also involves straight-up stress. The sweaty palms, shaky breaths, and racing pulse we associate with seeing our crush are thought to be the result of adrenaline (also know as epinephrine) at work — the same hormone that surges when a person sky dives or receives a jab with an EpiPen. While a little bit of stress goes a long way in making one’s crush seem like a real emotional investment, chronic stress can lead to serious psychological and physical health conditions, including anxiety, insomnia, muscle pain, high blood pressure, and a weakened immune system, according to the American Psychological Association.

prairie voles OMSI
When prairie voles get dosed with oxytocin and vasopressin, they get deeply attached to each other -- but that doesn't mean they'll get it on.

5. Attachment issues

Whoever labeled oxytocin the “love hormone” was grossly generalizing: While the famous neuropeptide, which is associated with cuddling, orgasms, and parent-child bonding certainly is involved in the attachment phase of love, its effects don’t increase linearly (notice a pattern here?). Oxytocin may seem like it facilitates deep social connections, but it can also have antisocial effects; as a study in Current Opinion in Behavioral Sciences pointed out in 2015, oxytocin also plays a role in fear conditioning, stranger avoidance, and aggression. Even when it does increase loving feelings toward one person, it may come at the cost of increasingly discriminatory feelings toward others. In other words, there’s a lot that scientists know about oxytocin’s “prosocial” effects, but using it to induce long-term bonding between humans — controversial nasal sprays already exist — can be risky.

The good news is that studies on prairie voles have been promising: By artificially manipulating levels of oxytocin and vasopressin (another neuropeptide involved in bonding) in the famously monogamous animals, scientists were able to induce deep feelings of attachment between individual animals. Still, feelings of attachment didn’t necessarily translate into sex — not all of the newly bonded animals ended up mating.

Photos via Flickr / theNerdPatrol