Diabetes mellitus is a metabolic disorder in which a person fails to produce adequate insulin or insulin reactions to cells, so that blood sugar levels are high in diabetes patients. Nanoparticles of small particle size have very significant effects against other types of dosage. Diabetes is treated with metal oxide-like nanoparticles such as zinc oxide, silver oxide, cerium oxide, magnesium oxide, vanadium oxide, chromium oxide, and gold nanoparticles. Different plants are used for the green synthesis of zinc, silver, magnesium oxide, cerium oxide, and golden nanoparticles. These analyses include separate in vitro and in vivo tests. The in vitro studies include nanoparticles characterization, antioxidant studies, anti-diabetic studies, and green synthesized nanoparticles phytochemical studies. In the in vivo trials, the animal research involves a range of test models, diabetes induction, experimental design, sample collection, and blood sample characterization by different testing methods. Studies in in vitro and in vivo reveal nanoparticles of metal oxide to be anti-diabetic. Graphical Abstract: [Figure not available: see fulltext.] © 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.