Metformin has been a cornerstone in the management of type 2 diabetes mellitus (T2DM) for more than 50 years, either alone or in combination with other therapies. This oral antihyperglycemic agent, also known as dimethylbiguanide, plays a crucial role in regulating noninsulin-dependent diabetes mellitus and is widely prescribed globally for various medical conditions. Recent advancements in its formulations have aimed to increase its effectiveness, tolerance, and nonglycemic effects. This review critically evaluates the analytical methods used to assess metformin formulations, including chromatographic and spectroscopic techniques, with a focus on sensitivity, specificity, and reliability. Comprehensive literature from various scientific databases was searched to gather information on metformin. Various formulations of metformin HCl, including hydrogels, solid dosage forms, mucoadhesive patches, lipospheres, and topical preparations, offer advantages like sustained release, improved bioavailability, and wound-healing potential. Analytical methods like RP-HPLC and UV-visible spectroscopy ensure the safety, stability, and accurate quantification of these formulations. These approaches support personalized treatment of T2DM, enhancing blood sugar control, therapeutic efficacy, and patient outcomes. This review offers valuable insights into metformin formulations and analytical aspects that researchers and pharmaceutical experts benefit in the further development and evaluation of metformin formulations.