Oral Calcitonin salmon treatment dose-dependently attenuates fasting and non-fasted hyperglycaemia during the intervention period. At the end of the study period, oral Calcitonin salmon treatment by dose decreases diabetic hyperglycaemia by ~9 mM and reduces HbA1c levels by 1.7%. Furthermore, a pronounced reduction in glucose excursions is dose-dependently observed for oral Calcitonin salmon treatment during oral glucose tolerance test. In addition, oral Calcitonin salmon treatment sustains hyperinsulinaemia and attenuates hyperglucagonaemia and hypersecretion of total glucagon-like peptide-1 predominantly in the basal state. Lastly, oral Calcitonin salmon treatment dose-dependently improves pancreatic beta-cell function and beta-cell area at study end.