Why using an em dash in your writing makes people suspect you’ve used AI

Posted on 7th July 2025

A TikToker called Sawyer has gone viral with this video saying he failed an assignment because he used the em dash in his paper – which his professor said was a giveaway that he’d used AI to write it.

ChatGPT, Grok and Gemini make liberal use of the long em dash to punctuate their responses instead of the shorter en dash.

As a result it’s become seen as a sign you’ve used AI in your writing—despite the fact you might always have been a keen em dash user (see what I did there – or was it AI?).

This is even more the case in the UK where the em dash is seldom used today and the shorter en dash – like the ones I’ve surrounded this clause with – has long been most writers’ preferred way to break up sentences and make them more readable and natural-sounding than using commas, parentheses, colons or semi-colons.

TikToker's story is not what it seems

More than 10 million people have watched Sawyer’s TikTok where he says: “My professor just told me that because I used an em dash in my paper it's 100% AI and I get a zero on the assignment.”

His video’s had nearly a million likes and more than 6,000 comments with lots of people horrified at his treatment, saying things like:

• "Only informed writers use em dashes—now we’re being punished? Tell your professor he’s discriminating against expertise and discouraging learning the English language."

  
  

• "Professor here. Go directly to their department chair, universities have not found a way to 100% accurately detect AI.”

  
  

• "As a professor who loves the em dash, this kills me. I hope you are able to advocate for yourself. “

  
  

• "It’s the best way to introduce something dramatic and add something different than just commas … newsflash people came up with it not AI"

But Sawyer’s TikTok is not all it seems on the surface. Most people are missing the fact that he’s promoting a tool called GPTZero that claims to detect whether AI has been used in a piece of writing.

He regularly posts similar TikToks claiming he and his fellow students have been accused of using AI in their work – to the point where you’d think he must be the unluckiest student in the world! But many of his posts are marked “paid partnership” and his TikTok bio says he’s a GPTZero ambassador.

There are plenty of people pointing it out among the 6,000 comments too:

• "Guys this just an AD for the AI detector"

  
  

• "OP turned out to be advertising software for detecting AI. No professor or academic would mark a paper 0% because of an em dash, there would have to be several telltale signs."

  
  

• "This video is an ad for gptzero. Every one of his videos are like this and every single comment he responds to says the same thing"

Stick to the en dash in the UK

In the US, where the em dash is quite commonly used by academics, authors and journalists, you might be on safe ground challenging anyone who claims you’ve been cheating by using AI.

In the UK you’ll have a harder job. In the 20th century the en dash started to replace its longer cousin as the dash of choice for British writers to separate clauses in sentences.

As a result, anyone using an em dash is assumed by British writers to be American – or, now, someone who’s secretly been using AI and doesn’t know their ens from their ems.

If you’re making a lot of use of tools like Chat GPT – and who isn’t? – here’s what to get right:

Hyphen - Smaller than a dash, the hyphen is used at the end of a line if the word breaks on to the next line and for some multipart words like tip-off or phrasal adjectives like fast-moving. It shouldn’t be used as a dash to punctuate sentences – though in the days of the typewriter it was the only key for a dash. Typists would sometimes use two hyphens -- to emulate the en dash typographers used.

En dash – Traditionally half the size of an em dash, the en dash is a versatile punctuation mark that helps you indicate a longer pause than a comma or – in pairs – to separate a parenthetical phrase. It’s also used like a colon – to introduce or give emphasis to the following phrase. The en dash should always have two standard character spaces either side of it.

Em dash—Used in the same way as the en dash but without spaces either side of it. It’s still commonly used in the US but not in the UK. Canadian writer Robert Bringhurst, in his influential The Elements of Typographic Style, said: “The em dash is the nineteenth-century standard ... it is too long for use with the best text faces. Like the oversized space between sentences, it belongs to the padded and corseted aesthetic of Victorian typography.” Writing in 1992, his recommendation: “Use spaced en dashes – rather than em dashes or hyphens – to set off phrases.”

It’s often stated that the em dash is so called because it’s the width of a capital M in any text size while the en dash is the width of a capital N. But em and en are actually units of typographic measurement. In the days of hot metal printing the em was equal to the length of a piece of type from top to bottom. The en was half the size of the em.

AI needs a keen editorial eye

So if you’re using AI to do some research or just to get you started and avoid “blank page syndrome” don’t fall into the trap of inadvertently carrying across a load of em dashes that makes an experienced reader think you’ve been cheating.

You can try telling ChatGPT not to use em dashes but, as some of the comments on Sawyer’s TikTok show, it just can’t break the habit:

• "I keep asking ChatGPT to stop using em dashes and it can’t do it. It just keeps using them."

  
  

• "Chat is ADDICTED to the em dash. I have a rule saved not to use the em dash. I have told it to remember that I hate the em dash ... it still uses the em dash. And if I do multiple drafts of a text ... eventually the em dash comes back"

Using AI with Shooglebox

Shooglebox gives you a powerful set of AI tools that can act like a super-efficient assistant to a good writer or editor – not a replacement for them.

We used one of the tools to extract and analyse the 6,000+ comments on Sawyer’s TikTok before checking the results and writing the blog post.

If you try getting Chat GPT, Grok or Gemini to do the whole writing job you’ll find they often repeat errors from other published articles and miss nuance, like differences between American and British usage. And they’ll no doubt overuse that em dash!