This pilot study is a double blind, randomized controlled trial designed to determine the significance of the combination therapy of phentermine and B12 injections among the obese population. The study population will be recruited from the ECU Physicians Internal Medicine clinic. Physicians will select patients meeting inclusion and exclusion criteria from their clinic to be approached for recruitment. Approximately 30 patients will be recruited and blindly randomized to either the treatment group (phentermine and B12 in combination) or the control group (phentermine alone). Patients will be randomized by means of block randomization in a 1:1 ratio. Neither patients nor study team members will be aware of group assignments through the entire duration of the study. Once randomized, both groups will begin taking 37.5 mg/day orally of phentermine as well as receive weekly intramuscular injections of either 1000 mg B12 or Saline depending on their group assignment. The study will consist of approximately 15 visits over the course of 3 months.