International investments are needed to support global sustainability. International investment law offers protections to foreign investors to encourage them to invest, but these same protections may make governments hesitant to regulate for the good of the environment or communities. To make investment law more sustainable, there are efforts underway to change the text of the treaties to enhance states' regulatory flexibility. This article first examines how investment law fits within the general international law framework. It then examines how traditional protections are being adjusted and warns that such changes are not enough to ensure sustainability.