Subcutaneous (SC) injection is a safe and effective way to administrate monoclonal antibodies (mAbs) and very often valued by patients and healthcare providers alike. A SC injection offers noteworthy advantages over intravenous (IV) injections, such as lowering hospital and clinical costs. Additionally, SC injections requires a lower number administration and allows for self-administrated or caregiver-supported dosing at home, thus a reduced healthcare resource utilization and healthcare provider time. In recent years biotherapeutics have been one of the fastest growing class of drugs in the pharmaceutical industry due to effective therapeutics with target specificity and potency. Biopharmaceuticals are usually administrated through IV, intramuscular (IM) or SC injection. However, patients are not administrated drugs, they are administrated formulations containing a drug. It is also important to recognize that biopharmaceuticals that are meant for SC injection are usually formulated at an acidic (4-6) pH, which can be attained by using a variety of excipients and stabilising agents. Excipients such as sugar, salt and surfactant are commonly found in biopharmaceuticals and can be used to attain a multi-year shelf life. Additionally, biopharmaceuticals can form aggregates and this occurrence happens due to loss of a stabilizing excipient. Hence the importance of understanding how and why different excipients are or can be used in a formulation.