Ham's F-12K (Kaighn's) medium is an improved version of Ham's F-12 nutrient mixture.
The culture medium has been supplemented with L-Alanyl-L-Glutamine in place of L-Glutamine. Compared with L-Glutamine, L-Alanyl-L-Glutamine is much more stable, releases less ammonia in culture, and improves cell viability and growth.
This medium does not contain proteins or growth factors, so it is usually necessary to supplement it with fetal bovine serum (FBS) and growth factors. The concentration of FBS required varies among different cell lines, and it is recommended to optimize it for specific cell types. Additionally, Ham's F-12K uses a sodium bicarbonate buffer system (2.5 g/L), and it should be used in an environment with 5–10% CO₂ to maintain physiological pH.