A year ago, Instagram made sweeping changes to the account settings of its teenage users after growing scrutiny from parents and lawmakers over child safety issues.

On Tuesday, it took them a step further.

Instagram, which is owned by Meta, said it would begin limiting the content its teenage users can see, based on the PG-13 ratings system used by the film industry. The policy, which will roll out by the end of the year, will also apply to conversations with the company’s artificial intelligence chatbots, which lawmakers are investigating for having inappropriate sexual chats with children.

By choosing the PG-13 standard, Instagram aims to make its new policy familiar to parents, said Max Eulenstein, the app’s head of product management. PG-13 movies are generally allowed to have some swear words, mild violence and partial nudity, although Meta said it would not recommend content with nudity to teen users.

“Our North Star in the teen experience is parents and what they’re telling us they want for their teens, and that’s what led to this development and why we focused on the PG-13 standard,” Mr. Eulenstein said in an interview.

Meta, which also owns Facebook, WhatsApp and Messenger, has long contended with concerns over how its apps affect children and has promised to protect minors from inappropriate content since 2008. Mark Zuckerberg, the company’s chief executive, has been grilled by lawmakers over child safety issues. Meta faces personal injury lawsuits in state and federal court that accuse it of harming young people with an addicting product.

Instagram has hundreds of millions of teenage users, and the changes are its most significant update to teen content moderation since last year’s policy overhaul, Mr. Eulenstein said. As part of those initial changes, the accounts of people under 18 were made private by default, which meant that only followers specifically approved by an account holder could see their posts.

We are having trouble retrieving the article content.

Please enable JavaScript in your browser settings.

Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.

Thank you for your patience while we verify access.

Already a subscriber? Log in.

Want all of The Times? Subscribe.