Professor Axen is a research scientist in the field of nutrition. She has been a full-time faculty member at Brooklyn College since 1983. She has taught a dozen different undergraduate and graduate courses in nutrition and has mentored many students in laboratory research, some of whom have completed their master's thesis with her. She has been the graduate deputy chairwoman (director) of the M.S. in Nutrition Program since its beginning in 1985. Her work at Columbia University focused on type 1 diabetes, in which auto-immune destruction of the pancreatic insulin-producing cells accounts for massive metabolic impairments. Her 2.5-year post-doctoral research fellowship in endocrinology at Albert Einstein College of Medicine elucidated aspects of the signaling mechanism for insulin release.

Since she came to Brooklyn College, Professor Axen's research has mainly concerned type 2 diabetes, the most prevalent form of the disease. Since expression of type 2 diabetes is strongly associated with obesity, Axen has used animal models of obesity to study the development and treatment of the disease. She has focused recently on the effect of diet composition on the development of insulin resistance, a condition in which insulin is less effective in its metabolic actions.