Three percent of front-page Amazon reviews are now AI-generated

AI-generated content has become the norm and can feature in everything from academic journals to news headlines and academic submissions. Now, it’s become clear that AI may be affecting our shopping habits.

Amazon was the first online retailer to introduce a customer review feature, but the system is potentially being manipulated by large language models (LLMs) like ChatGPT, Claude and Gemini. Leaving AI-generated reviews is an illegal practice under U.S. federal law, and to address this, Amazon is ironically tackling the problem with AI.

The company has stated that sophisticated tools are being used to flag suspicious review histories and remove AI-generated reviews before a customer encounters one.

Our Study

Our research suggests Amazon’s still has work to do.

At Pangram, we wanted to find out how many reviews on Amazon are AI-generated and whether they are more likely to be positive or negative compared to human-written ones.

To do this, we scraped 30,000 front-page product reviews across 500 of Amazon’s best-selling products through our AI detector. We looked at ten best-selling product categories, including baby, toys and games, laptops, medical devices, wellness and relaxation, beauty, and furniture. We recorded the star rating of each review, and whether it was a ‘Verified Purchase’ or not.

We found widespread evidence of AI reviews across Amazon best-sellers

We found that 3% of the total reviews studied - 909 total reviews - were AI-generated with high confidence. With increasing access to AI tools like ChatGPT Agent, content farms can automatically produce AI reviews at scale. Unless platforms take action, it will soon be hard to trust any reviews on the internet.

AI writes more five-star reviews than humans

Of the 500 Amazon best-sellers we analyzed, 74% of AI-written reviews gave products a 5-star rating. This compares to 59% of legitimate human reviews. The reverse is also true; humans wrote more 1-star reviews than AI, 10% vs 22%.

What about 'Verified Purchase' reviews?

The 'Verified Purchase' badge is often used as a reliable trust signal by customers: it shows that the reviewer actually bought the product. Our study found that 93% of the first-page AI-generated reviews (93%) had the 'Verified Purchase' badge, showing that this badge alone is no longer a reliable symbol of trust.

If a review was written by AI, how trustworthy is it?

Some reviews are likely written by sellers using LLMs to simulate feedback and push their product rating higher. Others may be written by well-meaning customers who don’t have the time to write one themselves or can’t find the words to describe their opinion of a product.

It doesn’t matter because the result is a potentially inaccurate depiction of a product.

If AI-written reviews are inflating product ratings, it could directly affect purchasing decisions.

To its credit, Amazon has been trying to address AI-created reviews, but based on what the study found, their efforts aren’t working well enough.

The volume of AI-generated reviews slipping through the cracks suggests Amazon still has work to do.

AI-generated reviews undermine trust, and when online reviews are one of the biggest things we rely on when deciding what to buy a product, we may start to doubt if a purchase is worth it.

How to spot AI-generated reviews

When reading reviews, look for mentions of specific product details. Generic comments or ‘fluffy’ language can be a sign that a review is AI-generated.

If you intend to leave a review, resist the temptation to use ChatGPT or another LLM. Your honest experience and opinion matter and could help people make an educated decision about purchasing a product.

You can also use Pangram’s AI detector to verify the reviews you're looking at are genuine. Our Chrome extension lets you select any text on the internet to check it for AI content.

Conclusion

Despite AI-generated reviews being illegal, they continue to slip through the cracks and mislead customers. Not even Amazon itself is able to catch all these reviews!

Businesses have a responsibility to ensure customers are receiving the truth about products, not the opinion of ChatGPT, so more must be done to prevent them from being published on e-commerce websites.