Efficacy of Platelet Rich Plasma Versus Placebo for Improvement in Olfactory Function in Adults With Olfactory Dysfunction: A Systematic Review and Meta-Analysis

Abstract

Background: Olfactory dysfunction significantly impairs quality of life. Conventional treatments such as corticosteroids and olfactory training offer limited and inconsistent efficacy. Platelet-rich plasma (PRP), a biologically active agent, has shown potential regenerative effects in olfactory neuroepithelium. This study systematically evaluates the efficacy of PRP compared to placebo in improving olfactory function. Methods: A systematic review and meta-analysis was conducted according to PRISMA guidelines and was registered in PROSPERO (CRD 420251045079). The databases searched included PubMed, Scopus, Embase, Central, and Web of Science. Seven studies (four RCTs, three non-RCTs) involving 789 patients were included. Subjective and objective outcomes were extracted and pooled using a random-effects model. Risk of bias was assessed using ROB-2 and ROBIN-I tools. Results: PRP was significantly more effective than placebo in improving subjective olfactory scores at 1 month (SMD = 1.16, 95% CI [0.29–2.03], p = 0.009), 3 months (SMD = 0.29, 95% CI [0.07–0.50], p = 0.01), and 12 months (SMD = 1.47, 95% CI [1.06–1.89], p = 0.00001). Objective testing also favored PRP at all timepoints, including 1 month (SMD = 1.55, 95% CI [0.36–2.73], p = 0.01), 3 months (SMD = 0.44, 95% CI [0.05–0.82], p = 0.03), and 12 months (SMD = 2.42, 95% CI [0.35–4.5], p = 0.02). Subgroup analysis showed younger age (< 40 years old) was associated with greater improvements. The safety profile was favorable with no serious adverse events reported. Conclusion: PRP demonstrates both short- and long-term benefits in olfactory recovery compared to placebo, especially among younger adults. Given the promising results and safety profile, PRP represents a viable treatment option for olfactory dysfunction. Standardization of PRP protocols and further high-quality RCTs need to be further explored.