Sometime in the last year, one piece of punctuation became a meme: the em dash (—). Post an AI-written comment on Reddit or X and the first reply is often just "nice em dashes" or "ChatGPT wrote this." It's now the fastest way to get a comment dismissed as AI. Here's why it happened, and how to fix it.
Why the em dash became an AI tell
The em dash isn't bad writing — professional authors use it well. The problem is density. Large language models were trained on heavily edited, published prose where the em dash is common, so they reach for it constantly: to join clauses, to insert asides, to set up a punchy ending. A model will drop three or four into a single paragraph. A real person dashing off a Reddit comment almost never does.
So it's not the em dash itself that reads as AI — it's the rate. Several per paragraph, plus the tic of using one for a dramatic pause before the final clause, is a pattern human casual writing just doesn't have.
The construction that makes it worse
The em dash rarely travels alone. It usually shows up inside the "it's not just X — it's Y" antithesis ChatGPT loves:
"It's not just a tool — it's a workflow."
That sentence shape, plus the em dash, plus a tidy three-part rhythm, is the trifecta readers now pattern-match to AI in under a second.
How to fix it
You don't have to ban the em dash — you have to bring it down to human levels:
- Replace most with a period. Split the sentence in two. "It's not just a tool. It honestly changed how I work."
- Use a comma where the pause is light.
- Use parentheses for a genuine aside (that's what they're for).
- Keep at most one em dash per paragraph, and never use it for the "X — but Y" reveal.
- Drop the antithesis. Say the plain version: "this saved me a ton of time," not "it's not just fast — it's effortless."
Before / after
AI: "Honestly — this is a game-changer. It's not just faster — it's a completely different way of working, and the results speak for themselves."
Human: "honestly this changed how I work. way faster, and the results actually held up."
Same point, zero tells.
The fast way
If you're posting AI drafts at any volume, fixing this by hand gets old. The free Prowlo Comment Humanizer strips the em dashes (and the antithesis, the "I hope this helps," the robotic structure) and rewrites in a real Reddit or X voice — and shows you which tells were in your original. Paste a comment, pick a voice, post something that reads human.
Related reading
- 17 signs a comment was written by AI
- The words and phrases that scream "AI wrote this"
- How to make ChatGPT sound human
- Humanize an AI comment now →
FAQ
Is the em dash a sign of AI writing? On its own, no — many humans love it. But a high density of em dashes, especially "not X — but Y" constructions, is the single most recognizable tell of ChatGPT text, so readers treat it as one.
Why does ChatGPT use so many em dashes? They're common in the edited prose models trained on, and they're a low-risk way to join clauses — so the model overuses them at a rate no casual writer matches.
How do I remove em dashes from AI text? Replace most with a period, comma, or parentheses, and keep at most one per paragraph. The free humanizer does it automatically.