What are the effects and efficacy of ozone therapy?

What Ozone Therapy Does

Ozone therapy has limited and inconsistent evidence for medical applications, with the most established use being environmental disinfection of surfaces and air rather than direct patient treatment. The evidence shows it is not recommended for most clinical conditions where it has been promoted.

Environmental Disinfection Applications

Ozone functions primarily as a powerful oxidizing agent that can inactivate viruses and bacteria through envelope alteration and structural damage 1.

Viral Inactivation on Surfaces

• Gaseous ozone effectively inactivates enveloped viruses including SARS-CoV-2, influenza A H1N1, MERS-CoV, and SARS-CoV-1 on surfaces and in aerosols 1.
• Low ozone exposures of 0.1–0.4 mg/L·min achieve approximately 4 log10 inactivation in aerosols 1.
• Exposures between 1–4 mg/L·min are needed for 3–4 log10 inactivation on different surfaces (fomites) 1.
• The mechanism works through peroxidation that damages bacterial and viral structures, inhibiting their reproductive cycle 1.

Personal Protective Equipment Disinfection

• Ozone can disinfect PPE including face masks, N95 respirators, and Tyvek fabric without affecting protective function, though elastic straps may be altered 1.
• CT values of 9.8 mg/L·min (or lower at 99% relative humidity) eliminate detectable SARS-CoV-2 genetic material from PPE 1.

Critical Safety Limitation

• Ozone is toxic to humans and rooms must be cleared to below 0.30 ppm (Short-Term Exposure Limit) or 0.10 ppm (Transitional Limit) before human re-entry 1.

Clinical Medical Applications (Limited Evidence)

Wound Healing - Mixed Evidence

For diabetic foot ulcers specifically:

• Ozone therapy may accelerate wound area improvement (66.54% reduction, 95% CI [46.18,86.90]) and reduce amputation rates (RR = 0.36,95% CI [0.24,0.54]) when added to standard care 2.
• However, it does not improve the proportion of completely healed wounds or length of hospital stay 2.

For other wound types:

• A small RCT on oxygen-ozone therapy for digital ulcers in systemic sclerosis showed efficacy on ulcer healing and pain reduction, but follow-up was only 20 days and blinded placebo-controlled studies are needed 1.
• Topical ozone showed no difference compared to standard care for diabetic foot ulcers in one high-quality study at 24 weeks 1.
• The evidence is insufficient and contradictory for chronic venous leg ulcers and other wound types 2.

Dermatological Conditions - Insufficient Evidence

• Clinical trials for acne, dermatitis, psoriasis, herpes, and other skin conditions have methodological limitations and do not demonstrate sound evidence for safe therapy 3.
• Only mild adverse effects occurred in most studies, with severe side effects rare 4.
• More high-quality studies with better methodological standards and longer-term safety assessments are required 3.

Musculoskeletal Applications - Not Recommended

For lumbar disc bulge and chronic low back pain:

• The American College of Physicians and American Pain Society do not recommend ozone therapy for treating lumbar disc bulge or chronic low back pain 5.
• Ozone injections are not supported by guidelines for chronic low back pain without radiculopathy 5.
• Conservative management should be tried for at least 6 weeks before considering any invasive procedures 5.

Mechanisms of Action

When used in appropriate concentrations, ozone acts through:

• Oxidative stress induction - damages viral envelopes and bacterial cell walls through peroxidation 1.
• Antimicrobial effects - bacteriolytic-grade disinfection with no residue 1.
• Potential antioxidant and anti-inflammatory effects at specific dosages, though mechanisms are not fully elucidated 6, 7.

Critical Limitations and Pitfalls

Evidence Quality Issues

• Most clinical studies have significant methodological limitations including lack of blinding, small sample sizes, and short follow-up periods 1, 3.
• Standard dosages for clinical efficacy and safety are not clearly established 3.
• The therapeutic window and optimal application methods remain poorly defined 7.

Common Misapplications to Avoid

• Using ozone therapy for conditions where it lacks evidence (lumbar disc disease, chronic pain) when evidence-based alternatives exist 5.
• Applying ozone therapy before completing adequate trials of conservative management 5.
• Assuming environmental disinfection efficacy translates to direct medical treatment efficacy 1.
• Ignoring the need for high humidity (often 99%) for optimal viral inactivation 1.

Current Evidence Summary

The strongest evidence supports ozone use for environmental disinfection of surfaces, PPE, and indoor spaces against viruses 1. For direct medical applications, evidence remains limited and inconsistent, with the possible exception of diabetic foot ulcers where it may provide adjunctive benefit for wound area reduction and amputation prevention, though not complete healing 2. Most clinical applications lack sufficient high-quality evidence to recommend routine use 1, 5, 3.

Human blood can tolerate appropriate ozone concentrations without acute or chronic side effects when used in controlled settings, though respiratory tract exposure must be avoided 7. The therapy requires precise medical ozone generators and careful dosing to avoid toxicity 7.