Intranasal Platelet-Rich Plasma With or Without Topical Insulin for Post-Inflammatory Anosmia

Inclusion Criteria: * Diagnosed with olfactory dysfunction despite olfactory training therapy * Loss of smell within the past 5 years * Loss of smell occurred after an infection * Platelet count is over 150,000 platelets per microliter Exclusion Criteria: Have a history of or currently have sinonasal tumours Have a history of surgery or radiotherapy for the base of your skull Have been treated with antibiotics in the past month before surgery Have a condition called systemic vasculitis or any bleeding disorder Have a suspected or known allergy to insulin or PRP or Platelet Lysate (PL) Have inhaled drugs (i.e cocaine) in the past 6 months of your enrollment Smell loss is due to a head trauma or after surgery Unable to complete the Sniffin Stick Smell test or questionnaires