L-Glutamine is an essential amino acid that is a crucial component of culture media and serves as a major energy source for cells in culture. L-Glutamine in liquid media degrades relatively rapidly when cultured at +37°C and toxic degradation products (ammonium ions) can interfere and cause damage to cells. Stable Glutamine is a stable dipeptide form of L-Glutamine. Unlike L-Glutamine, Stable Glutamine does not spontaneously break down to form ammonia. Instead, cells cleave the dipeptide bond to release L-Glutamine as needed. This system prevents waste build-up and maintains a fresh supply of L-Glutamine during long-term cultures. This solution is prepared in cell culture grade water.