HEPES buffer does not confer cytotoxic effects on cells and thus can be used in animal cell cultures. HEPES has been described as one of the best all-purpose buffers available for biological research. At biological pH, the molecule is zwitterionic, and is effective as a buffer at pH 6.8 to 8.2. HEPES has been used in a wide variety of applications, including tissue culture. It is commonly used to buffer cell culture media in air. HEPES finds its usage in in vitro experiments on Mg.