Intranasal Platelet-Rich Plasma With or Without Topical Insulin for Post-Inflammatory Anosmia (PRP-I RCT)

January 26, 2026 updated by: Amin Javer

Assessing the Effectiveness of Combined Intranasal Platelet-rich Plasma Plus Topical Insulin Versus Platelet-rich Plasma Alone in the Treatment of Post Inflammatory Anosmia: a Randomized Controlled Trial

This study evaluates whether adding topical insulin to intranasal platelet-rich plasma (PRP) improves smell recovery in adults with post-inflammatory anosmia. Participants will be randomly assigned to receive either intranasal PRP combined with topical insulin or intranasal PRP alone. Changes in olfactory function will be assessed over time to compare the effectiveness and safety of the two treatments.

Study Overview

Detailed Description

Post-inflammatory anosmia is a common cause of persistent olfactory dysfunction with limited effective treatment options. Platelet-rich plasma (PRP) has been proposed as a regenerative therapy due to its high concentration of growth factors, while topical insulin has demonstrated potential neurotrophic and anti-inflammatory effects in olfactory tissue.

This randomized controlled trial aims to evaluate whether the addition of topical insulin to intranasal PRP provides greater improvement in olfactory function compared with intranasal PRP alone in adults with post-inflammatory anosmia. Participants will be randomly assigned to receive either combined intranasal PRP plus topical insulin or intranasal PRP alone.

Olfactory function will be assessed at baseline and at predefined follow-up time points using validated smell testing methods. Safety and tolerability of the interventions will also be monitored throughout the study. The results of this study will contribute to understanding the potential role of regenerative and neurotrophic therapies in the management of post-inflammatory anosmia

Study Type

Interventional

Enrollment (Estimated)

20

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: PRP Plus Topical Insulin
Participants receive intranasal platelet-rich plasma in combination with topical insulin.
Autologous platelet-rich plasma administered intranasally with the addition of topical insulin applied to the olfactory cleft.
Placebo Comparator: PRP Alone
Participants receive intranasal platelet-rich plasma with saline instead of insulin.
Autologous platelet-rich plasma administered intranasally with saline applied in place of topical insulin as a placebo comparator.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Olfactory Function
Time Frame: Baseline to 12 months post-intervention
Change in olfactory function from baseline as measured using a validated smell identification test.
Baseline to 12 months post-intervention

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

March 30, 2026

Primary Completion (Estimated)

December 30, 2026

Study Completion (Estimated)

January 1, 2027

Study Registration Dates

First Submitted

January 26, 2026

First Submitted That Met QC Criteria

January 26, 2026

First Posted (Actual)

February 3, 2026

Study Record Updates

Last Update Posted (Actual)

February 3, 2026

Last Update Submitted That Met QC Criteria

January 26, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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