Insulin (In) based formulation has been used over decades for the cure of In-dependent diabetic patients, however, more attempts are still required to improve the remedial use of In. In this regard, the use of green tea has become widespread nowadays. However, it is unknown that (+)-catechin hydrate (CAT), a major component of green tea which enhances anti-diabetic activity of In, will or will not enhance the structure and stability of In if ingested with sugars. Interestingly, by using biophysical techniques, present study reveals the fact that the use of sugar during the intake of green tea extract may produce unwanted effects on In which may further lead to some disorders associated with In stability and also create obstacle in successful implications of In formulations. Copyright © 2018 Elsevier Inc. All rights reserved.