This striking result was attributed to two effects on the cancer cells. One was an effect of insulin to increase the trans-membrane transport of the methotrexate into the cell. While it may seem highly undesirable for a cancer therapy to actually promote cancer cell growth, this is in fact a valuable effect of insulin here. Chemotherapy side-effects result from actions on the cells of patient's hair follicles, their bone marrow, and the cells lining the stomach and intestines. This is what causes the hair loss, low blood cell counts, and the nausea and vomiting.
Chemotherapy drugs like to attack rapidly dividing cells, indiscriminately.
In a tumor, not all the cancer cells are in this rapidly dividing stage all at once. They take turns. In Insulin Potentiation Therapy, insulin administration does cause the blood glucose to go down. This is called hypoglycemia. This hypoglycemia is an anticipated side-effect of the insulin, one rapidly and effectively controllable with intravenous glucose infusions at an appropriate time, according to the IPT protocol.