QuillBot Doesn't Work for Turnitin Anymore

I'm not speculating. I tested it. Multiple times, multiple essays, multiple QuillBot modes. Here's what happened.

The Test

I generated five essays using ChatGPT-4. Standard college assignments: a psychology paper, a history analysis, a literature review, a sociology essay, and a business case study. Each was about 1,000 words.

I ran each essay through QuillBot using every available mode:

• Standard
• Fluency
• Formal
• Creative
• Expand
• Shorten

Then I submitted every version to Turnitin.

The Results

The "Creative" mode performed best, dropping detection by about 15-20 percentage points on average. But 71-82% AI is still firmly in "you're getting flagged" territory. Most professors treat anything above 20-30% as a concern.

Why QuillBot Stopped Working

QuillBot is a paraphrasing tool. It replaces words with synonyms and restructures sentences. That's it. It doesn't change:

• The underlying argument structure
• The logical flow between paragraphs
• The ratio of claims to evidence
• The level of analytical depth
• The predictability of the overall text

Turnitin's AI detector doesn't just look at individual word choices. It analyzes patterns across the entire document. The way AI organizes information, transitions between ideas, and balances paragraphs is different from how humans do it. QuillBot changes the surface. Turnitin looks deeper.

On top of that, Turnitin specifically trained their 2025 update on paraphrased AI text. They collected thousands of samples of AI essays run through various humanizer tools and taught their detector to recognize those patterns. QuillBot's output is now part of what Turnitin is trained to catch.

The Quality Problem

Even if QuillBot somehow dodged detection, the output quality is getting worse. Here's a real example:

Original ChatGPT sentence:
"Social media platforms have fundamentally altered how adolescents form and maintain peer relationships."

QuillBot Creative mode:
"The way young people create and keep up friendships has been basically changed at its core by social media sites."

That's not better writing. That's worse writing that also sounds awkward. "Changed at its core" is clunky. "Social media sites" is weirdly informal for an academic paper. "Keep up friendships" sounds like a middle school essay.

A professor reading this wouldn't think "this was written by a human." They'd think "this was written by someone who doesn't know how to write." Which is its own problem.

What About the Other Modes?

Standard mode barely changes anything. Detection drops maybe 10 points.

Fluency mode actually helps with grammar and readability but doesn't affect AI detection scores at all.

Formal mode makes everything sound like a legal document. It increases formality without decreasing AI signals.

Expand mode adds filler words and unnecessary phrases. Your essay gets longer but not better, and the padding looks suspicious.

Shorten mode is actually useful for editing but it condenses AI text into more concentrated AI text. Detection scores sometimes go up.

What to Use Instead

If your goal is to produce essays that pass Turnitin and are actually good:

For research and sources: Use Google Scholar, your university library, or a tool like Essay Press that builds essays around verified academic sources. Real sources are the foundation. Without them, you're building on sand.

For drafting: Use AI to generate outlines and rough drafts, then rewrite substantially in your own voice. Not paraphrase. Rewrite. Change the argument structure. Add your own examples. Remove sections you don't agree with.

For editing: Grammarly or even ChatGPT itself are fine for catching grammar issues, suggesting clearer phrasing, or tightening up your writing. This kind of AI use doesn't trigger detection because you're editing human-written text, not disguising AI-written text.

For nothing: QuillBot, Undetectable AI, StealthWriter, or any other paraphrasing/humanizing tool. They cost money, they don't work, and they make your writing worse.

The Money Angle

QuillBot Premium costs $119.88/year. That's not nothing for a college student.

For that same money, you could get access to better tools that actually solve the problem at its root. Or you could buy yourself a good style guide and improve your actual writing. Or you could buy 12 large pizzas, which would be a better investment than paying for a tool that gets you flagged for academic dishonesty.

Bottom Line

QuillBot had its run. Turnitin caught up. If you're still relying on paraphrasing tools to get AI essays past detection, you're playing a game you've already lost. The detection tools are better than the evasion tools now, and that gap is only widening.

Switch to a source-based approach. Build essays around real research. Add your own thinking. That's what works in 2026.