Does iThenticate Detect AI Writing? What Researchers Need to Know

Yes, iThenticate can detect AI writing, but not by default. The feature is a paid add-on that your institution must license separately. If your institution has not purchased the AI writing detection capability, iThenticate will only run similarity checks on your manuscript.

This surprises many researchers who assume iThenticate is purely a similarity checking tool. That assumption is correct by default, but it becomes wrong once the add-on is licensed. The FAQ says AI writing detection "is only available to customers that license Turnitin Originality," and iThenticate 2.0 customers fall into a separate category with its own licensing path.

Turnitin's FAQ addresses iThenticate directly. The FAQ says: "iThenticate 2.0 customers can get access to this feature if they license AI writing capabilities as an add-on." The next sentence in the FAQ reads: "If you are a Turnitin Similarity, Turnitin Feedback Studio (TFS) or Originality Check customer, please speak to your Turnitin account manager regarding access to AI writing detection."

This tells us two things. First, AI detection is not bundled into your standard iThenticate subscription. Your institution must pay extra for it. Second, iThenticate and Turnitin share the same underlying AI detection model, which is why the FAQ treats them under the same licensing section. The difference is not in the technology but in how you get access to it.

If you are unsure whether your institution has the add-on, the best step is to ask your Turnitin account manager or your library's iThenticate administrator. The presence of an AI Writing Report in your submission interface is the clearest signal that the feature has been licensed.

One common point of confusion is whether the similarity score and the AI score affect each other. The FAQ is explicit on this. Turnitin says: "The Similarity score and the AI writing detection percentage are completely independent and do not influence each other." The FAQ continues: "The Similarity score indicates the percentage of matching-text found in the submitted document when compared to Turnitin's comprehensive collection of content for similarity checking."

This means a manuscript can have a low similarity score and still flag a high AI writing percentage, or vice versa. The two metrics measure different things. Similarity checks compare your text against published works, web pages, and other submissions. AI detection evaluates the statistical patterns that characterize AI-generated prose. A clean similarity report does not guarantee a clean AI report.

For researchers who have only ever seen similarity reports, this independence is worth keeping in mind. A journal that runs both checks gets two separate assessments of your manuscript.

The AI Writing Report does not work in every language or file format. Turnitin's guidance, read on 21 August 2026, states: "File must be written in a supported language: English, Spanish, Japanese." The same page adds: "Accepted file types: .docx, .pdf, .txt, .rtf."

That language line is out of date, and the update is one iThenticate customers care about. Turnitin's release notes for 18 August 2026 announce "New AI detection writing detection capabilities for Modern Standard Arabic submissions", and the product updates page says it "will also be available to iThenticate 2.0 customers who currently license AI writing detection and have it enabled on their accounts." Four languages, then, not three. The guide above still shows three because it has not been edited since.

If your manuscript is written in a language outside this list, the AI detector will not process it. Among the known limitations, this language restriction is one that researchers submitting in languages like Chinese, French, or German should be aware of.

There is an additional layer of nuance with paraphraser and bypasser detection. The same page says: "Please note that only our English AI detector includes AI paraphrasing and AI bypasser detection capabilities." The next sentence reads: "At this time our Spanish and Japanese AI detectors do not include AI paraphrasing or AI bypasser detection capabilities." Arabic is not named there because that page has not been revised for it, but Turnitin's Arabic-language FAQ answers the point on its own page: AI paraphrasing detection is currently available only in the English detector. That page is written in Arabic; the English wording of it here is ours.

In practical terms, a researcher submitting in Spanish, Japanese or Modern Standard Arabic will get AI writing detection but not the paraphraser and bypasser layer. English submissions receive the full detection suite.

The practical takeaway is that you cannot assume your iThenticate submission will or will not be checked for AI writing. It depends entirely on your institution's licensing decisions, which you may not control.

Here is what we recommend:

1. Ask before you submit. Check with your institution's iThenticate administrator or your Turnitin account manager to find out whether the AI writing add-on is licensed.
2. Do not confuse a clean similarity score with a clean AI score. They are independent metrics. A low similarity percentage tells you nothing about the AI detection result.
3. Know your language coverage. If you write in English, you get the full AI detection suite including paraphraser and bypasser detection. If you write in Spanish, Japanese or Modern Standard Arabic, you get AI detection but not the paraphraser layer. Other languages are not supported.
4. Prepare your file in the right format. The AI Writing Report accepts .docx, .pdf, .txt, and .rtf. Make sure your manuscript is in one of these formats before submission.

To recap:

• iThenticate can detect AI writing, but only as a paid add-on for iThenticate 2.0 customers.
• The AI detection model is the same one Turnitin uses across its products.
• The similarity score and the AI writing percentage are completely independent.
• AI detection supports English, Spanish, Japanese, and, since 18 August 2026, Modern Standard Arabic. Paraphraser and bypasser detection supports English only.
• Accepted file types are .docx, .pdf, .txt, and .rtf.
• If your institution has not licensed the add-on, iThenticate will only run similarity checks.