TikTok has announced it will set a 60-minute daily screen time limit for users aged under 18.
But teenagers will be able to opt out of the new default setting, which TikTok said will be rolled out "in the coming weeks".
"If the 60-minute limit is reached, teens will be prompted to enter a passcode in order to continue watching, requiring them to make an active decision to extend that time," Cormac Keenan, TikTok's head of trust and safety, said in a blog post on Wednesday.
For accounts whose user is under the age of 13, a parent or guardian will have to set or enter an existing passcode to allow 30 minutes of extra viewing time once the initial 60-minute limit is reached.
The changes come as governments around the world are growing concerned about the app's security and ability to alter its algorithm to push certain posts and make the content highly addictive to young users.
TikTok said it came up with the 60-minute threshold by consulting academic research and experts from the Digital Wellness Lab at Boston Children's Hospital.
It said the research showed that being more aware of how we spend our time can help us be more intentional about the decisions we make.
Screen time recaps and a 'sleep reminder'
If teens opt out of the 60-minute default limit and spend more than 100 minutes on TikTok in a day, the platform will prompt them to set a daily screen time limit.
Every teen account will also receive a weekly inbox notification with a recap of their screen time.
"We want our community to feel in control of their TikTok experience," Keenan said.
Some of TikTok's existing safety features for teen accounts include having accounts set to private by default for those between the ages of 13 and 15 and providing direct messaging availability only to those accounts where the user is 16 or older.
TikTok said all users will soon be able to set their own customised screen time limits for each day of the week and set a schedule to mute notifications.
The company is also introducing a "sleep reminder" to help people plan when they want to be offline at night. When that set time is reached, a pop-up will prompt them to log off.
TikTok rabbit hole
There have long been concerns about what minors are exposed to on social media and the potential harm it might do.
A report released late last year suggested that TikTok’s algorithms are promoting videos about self-harm and eating disorders to vulnerable teens. Instagram, which is owned by Facebook parent Meta, has also faced similar accusations.
Social media algorithms work by identifying topics and content of interest to a user, who is then sent more of the same as a way to maximise their time on the site.
But social media critics say the same algorithms that promote content about a particular sports team, hobby, or dance craze can send users down a rabbit hole of harmful content.
In the US, families have struggled with limiting the amount of time their children spend on the Chinese-owned video-sharing app. According to the Pew Research Center, about two-thirds of American teens use TikTok.
In China, where TikTok's parent company ByteDance was formerly based, authorities in 2021 issued new rules restricting online gaming time for minors to only three hours a week - and only on Fridays, weekends, and public holidays - in an effort to curb Internet addiction.
Outside of exorbitant use by some minors, there is growing concern about the app around the world. The European Parliament, the European Commission, and the EU Council have banned TikTok from being installed on official devices.
That follows similar actions taken by the US federal government, Congress, and more than half of the 50 US states. Canada has also banned it from government devices.