The proposition was made following an incident this month when a man committed suicide on Facebook.
The Chinese-owned app had set out its proposal in a letter addressed to the chief executives of Facebook, Instagram, Twitter, Google, Twitter, Reddit, Twitch, and Reddit.
TikTok's interim CEO Vanessa Pappas noted that each of the platforms had its own policies to take down harmful content and stop its distribution.
"However, we believe each of our individual efforts to safeguard our own users and the collective community would be boosted significantly through a formal, collaborative approach to early identification and notification amongst industry participants of extremely violent, graphic content, including suicide," she wrote in the letter.
Pappas proposed a meeting of safety officers from each company to work out details of a collective approach, "which we believe will help us all improve safety for our users".
TikTok launched its own investigation after clips of the man's suicide were embedded into otherwise inoffensive videos shared widely on its global platform, which is especially popular with young teens.
The original video came from a Facebook livestream and showed an American man taking his own life, according to a warning TikTok sent to users on September 8.