Photobiomodulation in the management of persistent olfactory and gustatory dysfunction post-COVID-19: a systematic review

Among the clinical manifestations associated with SARS-CoV-2 infection, olfactory and gustatory dysfunctions have emerged as significant symptoms that impact patients’ quality of life, likely due to neural damage affecting the olfactory and gustatory pathways. Currently, there is no standardized protocol for managing these dysfunctions; however, photobiomodulation therapy (PBMT) has gained attention as a potential therapeutic approach due to its beneficial effects. This systematic review aimed to evaluate the current clinical evidence regarding the efficacy of PBMT in the management of persistent post-COVID-19 neurosensory dysfunctions. A comprehensive search was conducted in the PubMed, SciELO, LILACS, Embase, and Cochrane Central Register of Controlled Trials databases, from July 2023 to May 2025, identifying 465 records. The review of grey literature yielded eight additional eligible studies. Applying inclusion and exclusion criteria resulted in the selection of thirty-one studies for evaluation, with ten articles ultimately included in the qualitative analysis: one pilot clinical study, two case reports, three case series, and four randomized clinical trials. The efficacy of PBMT in treating neurosensory sequelae associated with SARS-CoV-2 infection was demonstrated with both red and infrared wavelengths, regardless of the therapeutic protocol adopted. Emerging evidence suggests that laser therapy–induced recovery of neurosensory dysfunction improves quality of life, especially in overall health perception and social well-being domains. However, to definitively establish its efficacy and optimize its clinical application, further high-quality research is necessary, including well-defined randomized clinical trials and standardized photobiomodulation protocols, to generate robust evidence capable of validating the clinical effectiveness of PBMT.

Not applicable.