Palmitoylethanolamide and Luteolin for Postinfectious Olfactory Disorders: How Clinically Meaningful Is Its Effect?

Abstract

Introduction: The prevalence of post-viral olfactory dysfunction has increased significantly during the COVID-19 pandemic, posing a major challenge for patients and practitioners. While olfactory training (OT) is a common approach to therapy, there has been increasing interest in supplementing therapy with a combination of palmitoylethanolamide (PEA) and luteolin (LUT), which are known for their anti-inflammatory properties. In this study, their efficacy in the treatment of patients with olfactory loss following upper respiratory tract infections, mainly COVID-19, was investigated in an outpatient clinic.

Methods: Fifty patients with persistent olfactory dysfunction were randomized to two groups: one receiving OT and PEA-LUT, the other OT alone. Olfactory function was evaluated before and after treatment.

Results: The study group showed significant improvements in odor discrimination and overall olfactory function (TDI score) after treatment with PEA-LUT and OT, while the control group did not. However, when clinically meaningful improvements were considered, there was no significant difference between the groups.

Conclusion: The present study suggests that while PEA-LUT may have the potential to improve olfactory function in post-viral dysfunction, the additional benefit over OT alone may be limited. These results contrast with some previous studies.

Keywords: Olfactory loss; Palmitoylethanolamide and luteolin; Upper respiratory tract infection patients.

Fig. 1.

Consort diagram showing enrollment, intervention, and follow-up of patients participating in the clinical study. PEA-LUT, palmitoylethanolamide and luteolin.

Fig. 2.

Effect of OT alone versus the effect of PEA-LUT and OT on TDI score to the first and the second visit of patients displayed in individual lines, Box-Whisker-Plot, and frequency curves.