Using platelet-rich plasma to treat parosmia

Randomized Clinical Trial of Intranasal Injection of Platelet-Rich Plasma for Treatment of Parosmia

Not applicable Interventional Stanford University · NCT06283745

This study is testing whether injections of platelet-rich plasma can help people with parosmia, a condition that causes distorted smells, feel better after having upper respiratory infections.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment40 (estimated)
Ages18 Years and up
SexAll
SponsorStanford University Academic / other
Locations1 site (Palo Alto, California)
Trial IDNCT06283745 on ClinicalTrials.gov

What this trial studies

This clinical trial evaluates the effectiveness of intranasal injections of platelet-rich plasma (PRP) in treating parosmia, a condition characterized by distorted smell. PRP, derived from the patient's own blood, is known for its anti-inflammatory and regenerative properties. The study will involve patients who have experienced olfactory distortion due to upper respiratory infections and will assess improvements in their olfactory function. Participants will also engage in concurrent olfactory training as part of the standard care.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 and older with parosmia resulting from upper respiratory infections and who have been experiencing symptoms for at least 6 months but less than 24 months.

Not a fit: Patients with olfactory loss due to trauma, chronic sinusitis, structural abnormalities, or neurodegenerative diseases are unlikely to benefit from this treatment.

Why it matters

Potential benefit: If successful, this treatment could significantly improve the quality of life for patients suffering from parosmia by restoring their sense of smell.

How similar studies have performed: Previous studies have shown safety and efficacy of PRP in treating olfactory loss, indicating potential for success in this novel application for parosmia.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Patients \>= 18 years of age
* Patients who have qualitative olfactory distortion
* Etiology of qualitative olfactory distortion is due to upper respiratory infection
* Quantitative score under the 10th percentile on the SSParoT (HedRang and HedDir)
* Quantitative score ≥ 8 on the QOD.
* At least 6 months of parosmia but less than 24 months
* Patients can have been previously treated with oral and topical steroids but this is not a requirement
* Patients will receive concurrent olfactory training - the practice of smelling strong odors (standard of care)
* Be able to read and understand English
* Be able and willing to provide Informed Consent

Exclusion Criteria:

* Patients \< 18 years of age, pregnant females, patients who have structural abnormalities on nasal endoscopy or radiographic imaging that would prevent injection into the olfactory cleft
* Olfactory loss due to trauma, chronic sinusitis / inflammation / polyps, neoplasms, or neurodegenerative diseases or patients who have had olfactory loss \> 24 months
* Patients with bleeding disorders or on blood thinners such as coumadin and plavix

Where this trial is running

Palo Alto, California

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Paraosmia
Last reviewed 2026-06-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.