Is 7-AAD cell-permeable?

7-AAD cells are not permeable, which means a variety of things. Firstly, it means that it cannot stain live and early apoptotic cells. These cells cannot be stained due to their membranes being intact. However, 7-AAD can stain dead and late apoptotic cells because their cell membranes are permeable and not intact. 7-AAD works like trypan blue, in the way that they both only stain dead cells and will not stain live cells. This again has to do with the membrane permeability of viable cells vs nonviable cells.