Like most things involving TikTok, it might only take a few tries to figure out how to watch a video in slow motion before you are once again an expert at all things related to the app. In this case, what you need to do is follow a few key steps and you will be on the fast track to watching that cooking TikTok or the one with the epic pool slide fail in slow motion to catch every glorious second.
First, when you’re on a video, press the three dots or little arrow in the bottom right hand corner of the screen. A menu should come from the bottom with the option to save the video to your device. Click on it and then open up Snapchat.
From Snapchat, open your camera roll and select the video you just saved from TikTok. It should pop up on your screen as a snap. Swipe to the right on the screen until you see the small snail icon and the video begins slowing down. You can then save the video.
Source : https://www.distractify.com/p/how-to-slow-down-tiktok-video