Background: The transfer factor (TF) is the dialyzable extract of leukocytes with cellular immunity transfer properties. Its use has spread in the treatment of a wide range of immunologic, infectious, and even oncological diseases. However, important aspects in their protein profile, component concentrations, and a well-defined action mechanism are not completely unknown. Objectives: To analyze the protein profiles of different transfer factors marketed in Mexico. Methods: 6 TF marketed in Mexico were obtained and analyzed, quantifying protein with thaze Bradford method, by high-performance liquid chromatography (HPLC), and polyacrylamide gel electrophoresis (SDS-PAGE). All samples were analyzed in duplicate. Results: The total protein concentrations of all TF analyzed are less than 0.2 mg/mL. The chromatographic profiles showed differences in some TF. The protein concentration was 6 to almost one thousand times lower compared to reports by some manufacturers. Conclusion: Almost all transfer factors marketed in Mexico lack a labeling and health record that meets the official standards.