A randomized, placebo control group, double blind clinical trial. 30 patients (male or female) from 40 to 65 years old with type 2 diabetes mellitus, less than 1 year of diagnosis, taking Metformin 850 mg daily, referred to the Experimental and Clinical Therapeutic Institute will be included.

All patients should give written informed consent prior to be enrolled. The protocol was previously approved by the local ethics committee (Experimental and Clinical Therapeutic Institute) of University of Guadalajara, registration number: CEI/489/2019. Patients with other medical conditions, taking additional drugs or with more than 1 year of evolution will be excluded.

The entire study consists of a total of 5 visits, the first one (day - 7) is the screening visit where written informed consent, clinical history, anthropometric measurements and blood samples will be performed.

The second or initial visit (day 0) consists of review of laboratory results, hemodynamic studies (i.e brachial - ankle pulse wave velocity and index for arterial stiffness and flow mediated dilation on brachial artery for endothelial function with VP1000 and UNEX EF devices respectively), and after randomization, start of intervention (either cassia cinnamon or placebo).

The third and fourth visits (day 30 and 60) consist of evaluation of treatment adherence, side effects, blood tests, treatment renewal and general recommendations.

The fifth and last visit (day 90) is similar to day 0 plus evaluation of treatment adherence and side effects. This is the end of intervention period.