AI-generated product demonstrations, makeup applications and dress twirls are spreading on TikTok Shop, raising tensions among creators, brands and the platform itself. TikTok provides artificial-intelligence tools for sellers on Shop, a multibillion-dollar marketplace where the company and creators get a cut of each sale they drive, as a way to further boost business.

But using the technology this way both undermines consumer trust in an increasingly important sales channel, according to critics, and competes with users who demonstrate products the old-fashioned way.

"I create ads for products that I have in person—real reviews, showing the actual product," said Rosemarie Soma, a so-called affiliate creator who promotes products on TikTok in exchange for commissions and aired her AI grievances in a video this spring. "It's very frustrating for affiliates because these [AI] videos are getting ad spend and are making sales."