EBO2 (EBOO) for Long COVID: What Has Been Studied

EBO2 (also called EBOO) is marketed to people with long COVID, the set of symptoms, including fatigue, brain fog, and shortness of breath, that can persist for months after a COVID-19 infection. Clinics frame the treatment as reducing inflammation and supporting cellular energy production, claims aimed squarely at the symptoms long COVID patients report, and some pages promote it alongside similar claims made for autoimmune conditions. This guide reviews what is actually known about long COVID, what published studies of ozone therapy and COVID-19 exist and what they tested, where those studies fall short of answering the specific long-COVID question, and where the real, well-funded long COVID research effort is happening instead.

What long COVID is and what is known about treatment

Long COVID, also studied under the term post-acute sequelae of SARS-CoV-2 infection (PASC), describes new or persisting symptoms weeks to months after a COVID-19 infection, including fatigue, cognitive difficulty, shortness of breath, and other complaints across multiple organ systems. Estimates of how many people develop it vary by study population and definition, but it has affected a large enough share of people who had COVID-19 to justify a dedicated, large-scale federal research program rather than case-by-case clinical guesswork. The National Institutes of Health launched the RECOVER initiative in 2021 specifically because so little was established about causes or treatment. As of this writing, RECOVER’s own site states that more than 550 drugs, medical devices, and other therapies have been submitted for consideration and that 4 treatment ideas have been selected for the first round of RECOVER-TLC clinical trials, alongside separately named trials already under way or completed, including RECOVER-NEURO, RECOVER-SLEEP, and RECOVER-VITAL [1]. Ozone therapy, EBO2, or EBOO is not among the interventions RECOVER has selected for trial, and it is not named as a candidate on RECOVER’s public homepage or in its published list of trials [1]. That an agency of this scale is still running trials to find out what works is itself informative: as of this writing, no treatment for long COVID has the kind of settled, guideline-level evidence base that Lyme disease or rheumatoid arthritis treatment has. Patients are often left piecing together symptom management on their own in the meantime, seeing multiple specialists for different symptoms with no single unifying treatment plan, which is exactly the gap alternative therapies, including EBO2, are marketed into.

What ozone studies actually exist

Contrary to the assumption that no one has studied ozone therapy in post-COVID patients, a search of the published literature turns up several relevant studies, though all involve major ozone autohemotherapy (MAH), the batch-style method of drawing blood into a bag, mixing it with ozone gas, and reinfusing it, not EBO2’s continuous filtration circuit. The strongest of these is a prospective, randomized, controlled pilot trial of 73 patients with post-acute sequelae of COVID-19, in which 35 patients received ozone autohemotherapy alongside conventional therapy and 38 received conventional therapy alone; the ozone group showed a significantly higher response rate on a symptom score, 71 percent versus 45 percent, along with improvements in walk distance and lung function measures, and the ozone group also showed better coagulation and inflammatory markers than the conventional-treatment-only group. The trial’s own authors describe it as a pilot and state that further research is needed to validate the findings and individualize the treatment regimen before drawing firmer conclusions [2]. A separate, uncontrolled report treated 100 patients with post-COVID fatigue using oxygen-ozone autohemotherapy under a named protocol and reported a 67 percent average reduction in fatigue scores, with no comparison group to establish how much of that change would have occurred anyway [3]. A third, retrospective review of hospital records for 40 patients given ozone autohemotherapy for a post-COVID syndrome diagnosis found improvement on several standard symptom questionnaires between before and after treatment, again without a control group [4]. An evidence map compiled by ozone-therapy society authors covering ozone and COVID-19 more broadly identified 13 clinical studies involving 271 patients in total, most of them testing autohemotherapy or rectal ozone insufflation in acute, sometimes hospitalized COVID-19 rather than long COVID [5].

Taken together, this is a real but small and early body of evidence: one actual randomized controlled trial with a positive result, described by its own authors as a pilot needing validation, plus a handful of smaller, uncontrolled, single-center reports, several of them associated with ozone-therapy professional societies rather than independent academic centers. None of it involves EBO2 or EBOO specifically, all of it involves batch-style major autohemotherapy, and the total number of long-COVID-specific patients studied across all of these reports is a few hundred.

Why acute-COVID data do not answer the long-COVID question

Most of the wider ozone-and-COVID literature, including the bulk of the studies in the evidence map above, treated acute, often severe or hospitalized COVID-19, measuring outcomes such as oxygen saturation, inflammatory markers, or mortality over days to weeks [5]. Long COVID is a different clinical problem: it is defined by symptoms that persist well after the acute infection has resolved, in patients who are typically not hospitalized at the time of treatment, and its proposed mechanisms, including lingering viral reservoirs, immune activation, or vascular and mitochondrial dysfunction, none of them fully confirmed, are debated separately from acute infection biology. A treatment’s effect on inflammatory markers during an active, severe infection does not establish an effect on fatigue or brain fog months later, even before considering that EBO2’s continuous-filtration approach has not been tested in either population.

Regulatory actions on COVID ozone marketing

Ozone therapy is not FDA-approved to treat any condition, including COVID-19 or long COVID [9]. During the pandemic, the FDA and Federal Trade Commission pursued enforcement action against marketers making unsupported COVID-19 treatment claims, including at least one case in which a federal court prohibited a Dallas wellness center from marketing ozone therapy as a COVID-19 treatment, an action the FDA lists among its fraudulent-product enforcement record alongside warning letters targeting colloidal silver, unauthorized test kits, and other unapproved COVID-19 products [6]. That action targeted acute COVID-19 marketing specifically, but it reflects the same regulatory position that applies to any ozone-based claim about COVID-19, acute or long: the agency has not evaluated or approved it, and has acted against claims that it works.

Risks and cost for a population already strained

Long COVID patients considering EBO2 face the same procedural risks described in the general explanation of the treatment: repeated venous access, a session lasting roughly an hour, and an out-of-pocket cost that clinics list from several hundred to well over a thousand dollars per session. One clinic markets an initial protocol of 6 to 12 EBOO sessions over 8 to 12 weeks, billed after a consultation fee credited toward the first session, and describes the treatment as addressing mitochondrial dysfunction, micro-vascular injury, and persistent immune dysregulation, three mechanisms proposed for long COVID itself, while also disclosing that the therapy is not FDA-approved to treat long COVID and that individual results vary and are never assured [7]. Another publishes patient testimonials describing the treatment as making inflammation “feel like it’s melting away” and reporting restored energy, without citing peer-reviewed research specific to long COVID [8]. This site’s clinic directory collects further examples of what clinics say and charge. For a population that frequently reports post-exertional malaise, where physical or physiological stress can worsen symptoms for days afterward, an hour-long procedure and the logistics of repeated appointments are themselves a cost worth weighing, separate from the dollar figure. The one controlled trial in this area, a pilot testing major autohemotherapy rather than EBO2, did track coagulation markers alongside symptoms and reported improvement rather than harm in its treated group, though this was a single small pilot study, not a safety trial, it did not test EBO2, and anyone with a known clotting disorder or other significant comorbidity should discuss any procedure involving blood withdrawal and reinfusion with their own physician before scheduling one [2].

Evidence-based options and clinical trials to look at

The RECOVER initiative’s own clinical trials, listed through its public site and on ClinicalTrials.gov, are testing specific candidate interventions for long COVID under controlled conditions and are a more direct way to access emerging treatments than an unstudied procedure sold outside any trial [1]. Standard long COVID care in the meantime generally involves working with a clinician on symptom-directed management such as paced activity and post-exertional malaise avoidance, treatment of specific complications as they are identified, and referral to a long COVID or post-viral clinic where one is available. None of this requires an unstudied procedure, and a clinician following this path can adjust it as new RECOVER-derived trial results are published, something a fixed, multi-week EBO2 protocol sold in advance cannot do.

Bottom line

Ozone therapy for post-COVID symptoms has been studied more than the other conditions in this series, including one genuine pilot randomized controlled trial with a positive result [2], but every one of these studies used batch-style major autohemotherapy, not EBO2, and all of them are small, mostly uncontrolled, and often tied to ozone-therapy professional societies [3][4][5]. Acute-COVID data on ozone cannot be assumed to apply to long COVID, a different, longer-lasting condition studied by a much larger, dedicated federal research effort that has not yet endorsed any single treatment, ozone-based or otherwise [1]. Long COVID patients are better served checking RECOVER’s own trials and working with a clinician on symptom management than paying out of pocket for a procedure whose best supporting evidence remains one small pilot trial of a different technique.