Does Turnitin detect QuillBot?
Yes
Yes. Turnitin added paraphrase detection specifically because spinning AI text through a paraphraser was the obvious workaround.
How it works
Paraphrasers rewrite word choice while preserving sentence rhythm and clause structure. Turnitin scores those structural regularities, and heavy paraphrasing tends to leave its own distinctive over-smoothed pattern.
The part people miss
Paraphrasing to dodge a score frequently makes the writing worse and the flag stronger at the same time.
Flagged for something you wrote yourself?
There is a right order to handle it in, and editing the document first destroys your best evidence.