Hypochlorous Acid (HOCl) Nasal Rinses: Evidence-Based Recommendations
The evidence does not support recommending specific over-the-counter HOCl nasal rinse brands, as current clinical guidelines prioritize standard saline irrigation for chronic rhinosinusitis, with HOCl showing only modest additional benefit over saline in limited research studies. 1
Current Guideline Recommendations
The American Academy of Otolaryngology-Head and Neck Surgery and European Position Paper on Rhinosinusitis strongly recommend standard saline irrigation as first-line therapy for chronic rhinosinusitis, emphasizing its proven efficacy in improving quality of life, mucous clearance, and symptom relief. 1
- Saline irrigation (not HOCl) is the evidence-based standard with demonstrated benefits in multiple Cochrane reviews and systematic reviews 1
- Guidelines specifically note that nasal irrigation should use isotonic or hypertonic saline solutions, with no mention of HOCl as a recommended additive 1
- The European guidelines evaluated HOCl in one double-blind placebo-controlled trial and found it produced significantly reduced SNOT-20 scores at 2 and 4 weeks compared to saline, but none of the other outcomes showed significant differences 1
Research Evidence on HOCl
While research studies demonstrate antimicrobial properties of HOCl, the clinical benefit over standard saline is marginal:
- Low-concentration HOCl (3.5 ppm) showed >99% bactericidal and fungicidal activity in vitro against common respiratory pathogens including MRSA, Streptococcus pneumoniae, and Haemophilus influenzae 2
- A randomized controlled trial (n=43) found HOCl irrigation resulted in significantly lower SNOT-20 scores at 2 weeks compared to saline placebo, but this difference was modest 3
- Post-surgical study (n=78) showed HOCl nasal spray had similar effects to saline irrigation in post-FESS care, with HOCl improving endoscopic scores while saline improved symptom scores 4
Critical Limitations of HOCl Products
HOCl solutions are inherently unstable, which raises concerns about over-the-counter product reliability:
- HOCl degrades rapidly when exposed to UV light, sunshine, air contact, and temperatures ≥25°C 5
- Optimal pH range of 3.5-5.0 is required to maintain HOCl as the predominant species; outside this range, the solution converts to less effective forms 6
- Presence of organic compounds or inorganic ions rapidly consumes HOCl through oxidation reactions, significantly decreasing microbicidal activity 5
- Storage requires dark and cool conditions (<10°C) to maintain HOCl concentration and activity 5
Practical Recommendation
Use standard isotonic or hypertonic saline irrigation as recommended by clinical practice guidelines rather than seeking HOCl-specific products:
- Large-volume irrigation (240-250ml) is more effective than nasal sprays for symptom relief and quality of life improvement 1
- Delivery methods include Neti pots, squeeze bottles, or pulsatile irrigation devices 1
- Homemade saline solutions are cost-effective compared to commercial preparations 1
- If considering commercial products, prioritize those with proven stability and proper storage rather than focusing on HOCl content 5
Important Caveat
The one guideline-level study evaluating HOCl showed only symptom score improvement without differences in endoscopic findings, disability indices, or adverse events compared to saline. 1 Given the instability concerns, lack of standardized OTC formulations, and marginal clinical benefit over standard saline, there is insufficient evidence to recommend specific HOCl nasal rinse brands over conventional saline irrigation that has decades of proven efficacy and safety data. 1