The move comes after the father of 14-year-old Molly Russell, who took her own life in 2017, said Instagram had "helped kill" his daughter.
Molly's family found she had been viewing graphic images of self-harm on the site prior to her death.
Adam Mosseri said Instagram was trying to balance "the need to act now and the need to act responsibly".
He added the site was "not where we need to be on the issues of self-harm and suicide".
