Last Updated on May 14, 2026 by Giorgia Guazzarotti

what botox does to your expression

Eer wondered what botox does to your expression beyond the obvious “face stops moving” part? People have been getting botox for decades now, mostly to soften frown lines or take the edge off forehead wrinkles that make them look stressed out even when they’re perfectly happy, and the whole conversation has basically stayed at the level of “it smooths wrinkles, it lasts three months, here are the potential side effects, bye.” Which is fine. But it’s also like explaining what a thunderstorm is and stopping at “the sky gets wet.” There is so much more going on. In this article, we’re going to get into what botox is actually doing – not just to your wrinkles or facial expressions, but to your brain, your emotions, and weirdly, your ability to understand other people’s feelings. And no, I’m not being dramatic. The science genuinely goes there.

What Is Botox Actually Doing To Your Face?

Botox is a brand name. The actual substance is botulinum toxin type A, which sounds terrifying and is, in enormous quantities, extremely dangerous. But in the tiny controlled doses used in cosmetic treatments it’s been used safely for decades. What it does is block the chemical messenger (acetylcholine, if you want the word) that tells your muscle to contract. So when it’s injected into, say, the muscles responsible for frowning (the ones that create those vertical lines between your brows) those muscles just can’t fully contract anymore. The nerve sends the signal, the signal goes nowhere, the muscle stays still, the skin above it stops creasing. That’s why the appearance of wrinkles reduces. No movement, no folding.

It’s also used on the orbicularis oculi muscles around the eyes for crow’s feet, on the frontalis muscle across the forehead for horizontal lines, and in smaller amounts in various other places depending on what someone wants. The paralysis from botox treatments is temporary. It tpically lasting somewhere between three and six months before nerve function gradually returns and the muscle starts working again.

Related: How To Fix A Crooked Smile With Botox

The Facial Feedback Hypothesis: How Your Face and Brain Talk to Each Other

Here’s something that Charles Darwin (yes, that Charles Darwin!) was already thinking about in the 1800s. He noticed that facial expression wasn’t just a result of emotion. It seemed to be part of how we experience emotion. Like, the feeling and the face weren’t just correlated. They were feeding into each other in a loop. This idea eventually became what scientists now call the facial feedback hypothesis. The basic idea is this: your facial movements send information back to your brain that helps regulate your emotional state. When you smile, your brain gets a little signal that something positive is happening. When you frown, same thing in the opposite direction. The expression of emotions reinforces the emotion.

Researchers have tested this in some genuinely creative ways. In one study, they had people hold a pen either between their teeth (which forces a kind of smile) or between their lips (which prevents smiling), and then had them read sentences with emotional content. The people who were accidentally forced into a slight smile processed happy sentences faster. Their brain, getting mild “we’re smiling” feedback from the face, was primed for positive emotional content. Botox, it turns out, is the perfect accidental tool to test whether this is actually real. Because it very specifically and temporarily shuts off one set of muscles while leaving everything else intact. Scientists basically looked at it and went: oh, we can use this.

Botox And Brain Activity: What fMRI Scans Actually Show

A 2023 study published in Scientific Reports took ten women who were getting cosmetic btx treatment anyway, injected their frowning muscles, and then scanned their brains while they looked at photos of happy and angry faces. Once before the injections, once two weeks after when the botox was fully active. What they found was that after the injections, brain activity in the amygdala (the part of your brain most directly involved in processing emotion) After botox, brain activity in the amygdala increased. The brain, cut off from its normal facial feedback, was working harder to make sense of the emotional faces it was seeing. But working harder doesn’t mean doing it better. Other studies measuring real-world outcomes found that people were measurably worse at reading other people’s emotions after botox injections, which suggests all that extra effort isn’t fully making up for what the paralysed muscles can no longer tell the brain.

An earlier study found something similar: when participants who’d had botox were asked to imitate angry expressions, the botox significantly reduced activation in both the amygdala and the brainstem (the brain regions most deeply tied to emotional experience). The researchers concluded that this was causal evidence that the amygdala is directly sensitive to facial feedback. Meaning: your face is not just a display screen for your emotions. It’s an active input into the system.

Botox And Social Situations: How It Affects Your Ability to Read Other People’s Emotions

Did you know we read other people’s emotions partly by unconsciously mimicking them? When someone smiles at you (like a real, genuine Duchenne smile that reaches the eyes), your face does a tiny, imperceptible micro-version of that smile back. You’re not aware of it. It just happens. And that little bit of mimicry is part of how your brain figures out what the other person is feeling. It’s like your face is doing a quick translation: let me try this expression on for half a second and see how it feels, so I know what it means.

A Botox procedure disrupts this. A study from USC and Duke found that people who’d received botox injections had a reduced ability to tell what other people were thinking and feeling. The reduced ability tracked specifically with the loss of facial feedback. Because the injected muscles couldn’t participate in that unconscious mimicry, the brain was working with less information. One of the researchers put it with a kind of bleak irony: “People use botox to function better in social situations. You may look better but you could suffer because you can’t read other people’s emotions as well.” Ironic, right?

A 2018 study in Scientific Reports tested this with a proper control group and found that BTX-treated participants showed measurably reduced emotion recognition ability compared to comparison participants. A 2010 study added something even more specific: after botox to the frown muscles, people took significantly longer to process angry and sad sentences – but their processing of happy emotions was completely unchanged. Because the muscles that frown were paralysed, but the muscles involved in smiling weren’t. 

I want to be clear: this is not a reason to panic if you’ve had botox. The effects are temporary, they correspond to when the botox is active, and they reverse when the muscle movement comes back. But it’s a fascinating thing that nobody seems to warn people about.

The FlipSide: Botox And Depression

While all that is going on, there’s also strong evidence that botox has a legitimate antidepressant effect. Multiple randomised controlled trials have tested whether treating the glabellar frown muscles specifically can improve depression symptoms. A double-blind placebo-controlled trial found that a single treatment to those frown muscles produced significant, sustained improvement in depression in patients who hadn’t adequately responded to antidepressant medication. A meta-analysis that pooled results from five separate RCTs found that botox patients showed significantly more improvement in depressive symptoms than placebo patients.

The mechanism is the same feedback loop, just working in your favour. If you physically cannot frown deeply, your brain receives less of the muscular feedback associated with negative emotions. The loop that would normally reinforce low mood gets interrupted. It’s sometimes called it a “depot antidepressant” because a single treatment lasts three to four months. 

But here’s the catch – and this is important. The effect depends entirely on which muscles you’re treating. One study found that treating laugh lines specifically was associated with increased depression scores. Because when you paralyse the muscles associated with expressing positive emotional responses, you potentially cut off some of the positive feedback those expressions send back to your brain. You smile less freely, your face communicates less happiness upward to your emotional processing system, and your mood takes a hit. The same mechanism, pointing the other way.

So the emotional effects of botox aren’t a blanket thing. They’re specific to the muscles you’re targeting. Frown muscles: potentially helpful for mood. Smile muscles: potentially the opposite. Which is an excellent argument for knowing your facial anatomy before deciding how much botox you want and exactly where.

The Bottom Line

The research here is genuinely preliminary: the fMRI studies have small sample sizes, future research is going to tell us a lot more about individual differences and whether these effects actually show up in real everyday social interactions or just in controlled lab conditions. The emotional processing changes are temporary. This is not a “botox is secretly destroying your empathy” situation for the gain of a youthful look.

But it is a good argument for having a real conversation about the psychological effects of botox before you commit to this cosmetic treatment. Not just “here are the side effects” boilerplate, but an actual discussion about what you want from it, which specific muscles you’re treating, how much movement matters to you, what natural expressions you want to preserve. The amount of botox and the injection sites are not a one-size-fits-all decision.  Your face is not a passive surface. It’s part of how you feel things and how you understand other people. Which is, if you think about it, a pretty extraordinary.