INS and diabetes mellitus: Despite the life saving properties of insulin, when there is a systematic deficiency either due to the systemic impaired insulin synthesis (type 1 diabetes mellitus) or the system itself became resistant to the hormonal effect (type 2 diabetes mellitus) the hormone must be injected in the system from external sources as insulin taken by mouth is rapidly destroyed in the digestive tract particularly due to tryptic digestion, and, as such the needed hormone is not adequately available in sufficient amount to make up for the systemic deficiency of the hypoglycemic protein.