Stable glutamine, a dipeptide form of glutamine, offers higher stability and minimizes levels of ammonia buildup in cell culture. Formulated in 0.85% saline for osmotic balance, the solution is often utilized where glutamine stability at elevated temperatures is an important consideration, such as in extended cell cultures. L-alanyl-L-glutamine stays in dipeptide form until utilized by cells, allowing a reliable supply of L-glutamine to be maintained in culture.