Polished My Essay With Notion or QuillBot and Now It Is Flagged as AI

If you ran your essay through a grammar checker and it got flagged as AI, the question is not whether the tool is "safe" in general. It is which feature of the tool you used. Turnitin's FAQ answers this directly for one product: Grammarly's spelling, grammar, and punctuation corrections are not flagged "in most cases," but content produced by Grammarly's generative features, including draft generation, paraphrasing, summarizing, and other features, "will likely be flagged as AI-generated." For Notion, QuillBot, and other tools, Turnitin does not publish a tool-by-tool list. The FAQ says its detector has been trained and tested to detect leading paraphraser and bypasser tools but that it cannot disclose which ones. The line is clear in principle even when the tool list is not: corrective edits and generative rewriting are different categories, and the detector reads them differently.

The FAQ contains a detailed answer about Grammarly specifically. The relevant passage is long, and every clause matters:

"No. Our detector is not tuned to target Grammarly-generated spelling, grammar, and punctuation modifications to content but rather, other AI content written by LLMs such as GPT-3.5. Based on tests we conducted on human-written documents with no AI-generated content in them, in most cases, changes made by Grammarly (free & premium) and/or other grammar-checking tools were not flagged as AI-written by our detector. Please note that this excludes content generated by Grammarly's generative AI-powered features, including draft generation, paraphrasing, summarizing, and other features. Content produced using these features will likely be flagged as AI-generated by our detector."

Read that sentence in two halves. The first half is an exemption: spelling, grammar, and punctuation fixes are not what the detector is tuned to catch, and in tested cases they were not flagged. The qualifier "in most cases" is doing real work there, because it means the exemption is not a guarantee. The second half is the boundary: generative features are a different category, and content from them is likely to be flagged. We took the whole passage apart in does Turnitin detect Grammarly as AI writing.

Grammarly is the only tool Turnitin's FAQ names by product. For Notion, QuillBot, and anything else, there is no published statement. What the FAQ does say is this:

"Our AI writing detector has been trained and tested to detect leading paraphraser and bypasser tools. However, to safeguard the integrity of our solution and its effectiveness in maintaining academic honesty, we're unable to disclose the names of these tools."

We cannot and will not tell you that a specific tool is safe or unsafe, because Turnitin does not publish the list, and we are not in the business of making detection claims. What we can say is that the Grammarly FAQ establishes a framework: corrective edits (fixing spelling, grammar, punctuation) sit on one side, and generative operations (drafting, paraphrasing, summarizing) sit on the other. If the tool you used has both kinds of functions, which button you clicked matters more than which app you opened. The same framing is why does Turnitin detect AI humanizers has no tool-list answer either.

There is a catch. The FAQ lists text that has been "paraphrased without developing new ideas" among the content that false positives can include. The full passage:

"Sometimes false positives (incorrectly flagging human-written text as AI-generated), can include content without a lot of structural variation, text that literally repeats itself, or text that has been paraphrased without developing new ideas."

And the following sentence: "If our indicator shows a higher amount of AI writing in such text, we advise you to take that into consideration when looking at the percentage indicated."

This means a paraphrasing tool can create a double problem. First, if it is one of the tools Turnitin has been trained to detect, its output may be flagged directly. Second, even if it is not detected as a specific tool's footprint, the resulting text may match the profile of writing that false positives cluster around: uniform structure, literal repetition, or paraphrase that shuffles words without adding substance. The first risk is detection. The second is resemblance.

One thing that adds to the confusion is that the AI score and the similarity score are independent. Turnitin states: "The Similarity score and the AI writing detection percentage are completely independent and do not influence each other." A paraphrasing tool can lower your similarity score (because the text no longer matches existing sources word-for-word) while simultaneously raising your AI score (because the output now resembles AI-generated or paraphrased text). These two movements are not contradictory. They come from two separate systems reading different signals.

We have seen this pattern enough times that we wrote a dedicated article about what happens when paraphrasing lowers similarity but raises the AI score.

To summarize what we have covered:

• Grammarly's spelling, grammar, and punctuation fixes are not flagged "in most cases," but its generative features (paraphrasing, summarizing, drafting) likely will be.
• Turnitin does not disclose which other tools it detects, so nobody can give you a verified "safe list."
• The function you used matters more than the app name: corrective edits and generative rewriting are different categories.
• Paraphrased text that does not develop new ideas is on Turnitin's own list of false-positive-prone content.
• The AI score and the similarity score are independent, so a paraphrasing tool can lower one while raising the other.

If your essay is already flagged, the productive question is not "was the tool at fault" but "which passages are flagged and why." Import your Turnitin report and work on the specific passages that were flagged. Eligible passages can be re-run at no charge.