Trial reportThe Laryngoscope2025
Effect of Olfactory Training in COVID-19 Related Olfactory Dysfunction-A Placebo-Controlled Trial.
Trial report in The Laryngoscope, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT05539560 (The Effect of Olfactory Training in Patients With COVID-19 Induced Olfactory Dysfunction - A Randomized Placebo-controlled Clinical Trial), which is not on this map. Cited by 2 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
The Effect of Olfactory Training in Patients With COVID-19 Induced Olfactory Dysfunction - A Randomized Placebo-controlled Clinical Trial
Who cites it
2 citing papers in PubMed.
- Effect of Olfactory Training in COVID-19 Related Olfactory Dysfunction-A Placebo-Controlled Trial.The Laryngoscope · 2025Trial
- Olfactory Training for COVID-19-Related Olfactory Dysfunction: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.Turkish archives of otorhinolaryngology · 2026Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
5 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
objectivesOlfactory training is a recommended treatment in patients with olfactory dysfunction after COVID-19. However, the effectiveness of olfactory training in COVID-19-induced olfactory dysfunction has been studied; only a few studies have included a placebo group to compare the effect of traditional olfactory training with odor-free olfactory training. In this randomized placebo-controlled trial, we evaluate the effect of olfactory training with essential oils versus olfactory training with placebo oils in patients with post-COVID-19 olfactory dysfunction.
methodsSixty-five patients with COVID-19 induced olfactory dysfunction were randomized to the intervention or control group. Patients in the intervention group performed classic olfactory training with four essential oils (orange, lavender, clove, and peppermint) twice daily for 12 weeks, while the control group performed the same olfactory training but with odor-free placebo oils. Olfactory function was assessed using the Sniffin Sticks extended TDI test at baseline and at follow-up after the 12-week intervention.
resultsThe intervention group did not significantly improve their olfactory function compared to the control group after olfactory training. Additionally, no associations were found between changes in olfactory function after olfactory training and age, gender, rhinitis, time since infection, or pre-infection vaccine. A regression analysis showed that the presence of parosmia was associated with reduced effectiveness of olfactory training.
conclusionsThis study found that 12 weeks of classical olfactory training is not effective in the treatment of COVID-19 induced olfactory dysfunction. Moreover, the study indicates that parosmia reduces the effect of olfactory training significantly. LEVEL OF EVIDENCE: 2:
trial registrationClinicaltrials.gov registration number: NCT05539560.
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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.