Various quality control tests are employed for solid dosage forms such as uniformity, dissolution and drug contents to assess their pharmaceutical equivalence. The objective of the current study was to assess and contrast five distinct metformin hydrochloride brands that are offered for sale in the Libyan market. The physicochemical equivalence of the five brands of metformin hydrochloride tablets (500 mg) was determined through the evaluation of official and non-official standards according to the USP including uniformity of weight, friability, hardness, dissolution rate and drug content. All the examined brands available in the Libyan market passed the official weight variation, friability, dissolution and disintegration tests and were equivalent. The friability test was found within the specified limit. All the formulations were disintegrated within 09-15 min. The tested brands were non-equivalent to the innovator Glucophage^® according to their dissolution evaluation. The percentage content of the active ingredient of five brands of metformin tablets showed values within the monograph specifications (95%-105%). In conclusion, all the five brands available in the Libyan market that were evaluated in this study cannot be substituted with the innovator product in clinical practice.