Ozone therapie gebruikt ozon, een reactieve vorm van zuurstof. Het wordt op vier manieren toegediend: geïnjecteerd in een gewricht of schijf, gemengd met afgenomen bloed en teruggevoerd, via het rectum toegediend, of op de huid aangebracht als geozoneerde olie. Gecontroleerde proeven ondersteunen slechts enkele lokale toepassingen. Bij een artrotisch kniegewricht verlichte ozon de pijn meer dan een corticosteroïdinjectie en ongeveer even goed als hyaluronzuur. Bij een hernia is het gerelateerd aan minder rug- en beenpijn.
Toegevoegd aan de behandeling van diabetische voetzweren versnelde het het genezingsproces en halveerde het de amputaties ongeveer. Die proeven zijn grotendeels klein en van lage kwaliteit. De brede claims over systemische detoxificatie en chronische ziekten zijn niet bewezen. De veiligheid hangt af van de toedieningsweg.
Findings & Outcomes
What It Is
Ozone therapy is the medical use of ozone (O3), a reactive three-atom form of oxygen, given in a limited dose and kept away from the airways. One word, ozone, covers treatments that differ in route, dose, evidence, and risk. A gas injected into a joint under imaging differs from a gas passed systemically, and both differ from breathing it.
Breathing ozone damages the lungs at any dose, and injecting the gas has caused gas embolism and stroke. Most of the risk comes down to the route and the dose.
Anatomy Of The Routes
1Intra-articular and local injection
A metered dose of oxygen-ozone gas is injected directly into a joint, most studied in the knee, or into or around a herniated spinal disc under imaging guidance. This is the route behind most of the pain evidence. Because it places gas into or near tissue and vessels, technique and imaging matter. It carries a gas-embolism risk.
2Autohemotherapy
In major autohemotherapy, a volume of blood is withdrawn, mixed with an ozone-oxygen mixture outside the body, and reinfused. This is the systemic route sold for fatigue, immunity, and chronic disease.
3Rectal insufflation
An ozone-oxygen gas mixture is introduced into the rectum as a systemic route that avoids a vein. It appears in some diabetic-foot and systemic protocols. Dose control and technique matter here as with other gas routes into the body.
4Topical: ozonated water and oil
Ozone is dissolved into water or bubbled into a vegetable oil to make ozonated oil, then applied to skin or wounds. This is the gentlest route and the one behind some wound-care signals. The reactive chemistry stays at the skin surface and does not enter the bloodstream.
5Inhalation: the route to avoid
Breathing ozone gas is toxic, so no protocol uses this route.
How It Works
The proposed mechanism is controlled oxidative eustress. A low, measured dose of ozone reacts briefly with blood and tissue to create a small burst of oxidative signaling. That signal is thought to switch on the body's own antioxidant defenses, chiefly the Nrf2 pathway and the enzymes it controls.
This is the same hormetic principle behind exercise and heat: a mild, well-dosed stress prompts an adaptive response that leaves the system more resilient. At a low dose ozone signals mildly; at a higher dose it becomes a potent oxidant and toxin, so the therapeutic dose must stay within a narrow window. A preliminary human study reported that ozone preconditioning activated the Nrf2 antioxidant pathway, a plausible result still under study. For the underlying biology, see hormesis and inflammation.
The Selling Points And The Evidence
The marketing picture is expansive: ozone is sold as a treatment that raises the body's oxygen, detoxifies it, and boosts immunity against a broad range of chronic disease. The part with a basis is narrow, and two things are supported.
- An active, studied mechanism: a controlled oxidative signal that can switch on antioxidant defenses.
- A few local uses, in knee osteoarthritis, some wounds, and diabetic foot ulcers, where controlled trials show short-term signals, mostly at low quality.
Everything the broad market adds on top of that is a stretch. Ozone does not meaningfully raise the body's oxygen, whole-body detoxification is not an established effect, and the pooled trial evidence reaches only a few specific conditions. Several of the broadest claims have no plausible mechanism.
What The Research Shows
The trial evidence clusters in three areas: the knee, the herniated disc, and diabetic foot ulcers.
Knee Osteoarthritis
The knee has ozone's best evidence, and it is still emerging. Pooling the controlled trials, a meta-analysis found that an ozone injection into the joint reduced knee osteoarthritis pain more than a corticosteroid injection over the short and medium term. The underlying trials were low quality. A double-blind randomized trial of 59 people showed lower pain scores against an oxygen-only control. Function improved too, including walking distance, range of motion, and the Timed Up and Go test. Head to head, a level-I meta-analysis of 424 patients found ozone and hyaluronic acid injections gave similar pain relief at four to six months.
The trials are small and short, concentrations and schedules vary, and the comparison is usually against another injection instead of a true placebo. The size of the effect is not settled. That makes ozone a short-term pain option with early support, set beside injections that carry more evidence and clearer guideline standing.
Back And Disc Pain
For a herniated disc, an oxygen-ozone injection into or around the disc, sometimes called ozone discolysis, is backed by many studies, but weak ones. A meta-analysis pooling roughly 8,000 patients reported a mean pain drop of 3.9 on a 10-point scale and a 25.7-point improvement in disability, both above the threshold that patients notice. The reported complication rate was low.
The weakness is quality. The pooled studies were mostly uncontrolled or low quality, the analysis was retrospective, and an industry affiliation was present. That leaves the figure above the true strength of the evidence, a preliminary signal only. Injecting gas near the spine carries a specific, if rare, risk of gas embolism.
Wounds And Diabetic Foot Ulcers
Diabetic foot ulcers are a complication of diabetes, so the foundation is the free, self-directed work: blood-sugar control, a whole-food diet, and proper foot care with offloading of pressure. Ozone enters as an add-on to that standard care, never as a replacement for it. Added to standard treatment, ozone has been linked to faster healing of diabetic foot ulcers, shorter hospital stays, and a roughly halved amputation rate in a meta-analysis of 960 patients. The same analysis found ozone did not clearly improve the rate of complete ulcer resolution over good standard care. A more recent umbrella review found the healing benefit no better than control. Topical ozonated oil or water is the most convincing form. A single older trial in people with type 2 diabetes reported improved blood-sugar and antioxidant markers over twenty days. It is one small, preliminary result.
The Broad Detox And Chronic-Disease Claims
An umbrella review of the pooled randomized evidence found usable meta-analyses for only four conditions, with mixed or low-certainty results even there. For COVID-19, ozone lowered a laboratory test result but did not improve hospital stay, intensive-care admission, or survival. A lack of trial support does not make a specific effect impossible, but the sweeping chronic-disease claims remain untested.
The Research & Studies
Everything here is based on the research we have collected and checked, sorted into groups and ordered with the strongest evidence first. Click any claim to open the studies behind it.
Pain
Ozone knee injection eased osteoarthritis pain at least as much as a steroid, and beat oxygen in a 59-person trial
An ozone shot into an arthritic knee eases pain in the short term about as much as a steroid shot does, in the trials done so far.
A 2026 systematic review and meta-analysis in Med Gas Res pooled controlled trials comparing intra-articular ozone with corticosteroid injection and found ozone gave greater pain reduction than corticosteroid over the short and medium term, while cautioning that the underlying trials were low quality and that only steroid and hyaluronic acid are guideline-recommended. A separate 2025 double-blind randomized trial (Adv Rheumatol, n=59, NCT06088706) gave weekly ozone at 20 or 40 micrograms per milliliter for four weeks and saw significant falls in visual-analogue pain scores versus an oxygen control, with no difference between the two ozone doses. The trials are small, short, and use varied concentrations and schedules.
Any benefit measured so far is short-term. If someone is weighing an ozone knee injection, the fair comparison is against steroid or hyaluronic acid injections that have more evidence and clearer guideline standing.
The studies · 2
Arias-Vazquez et al., ozone injections reduce pain in knee osteoarthritis · Med Gas Res 2026;16(3):286-292
Arjmanddoust et al., two doses of intra-articular ozone therapy in knee osteoarthritis, double-blind RCT · Adv Rheumatol 2025;65(1):11
Counts once: this finding and 1 other here come from the same source, so they are one body of evidence, not separate confirmations.
Oxygen-ozone disc injection tied to a 3.9-point pain drop across roughly 8,000 herniated-disc patients, in mostly low-quality studies
For a herniated disc, injecting an oxygen-ozone mix into or around the disc was linked to meaningfully less back and leg pain in a large pooled analysis, though the underlying studies were mostly low quality.
De meta-analyse uit 2010 in J Vasc Interv Radiol poolde twaalf onderzoeken bij bijna 8,000 patiënten behandeld met zuurstof-ozon voor hernia's in de lendenwervelkolom. De gemiddelde verbetering was 3.9 punten op de visueel-analoge schaal en 25.7 punten op de Oswestry Disability Index, beide boven het minimaal klinisch relevante verschil, met een verbeteringswaarschijnlijkheid volgens de gemodificeerde MacNab-schaal van 79.7 procent en een laag gepoold complicatiepercentage. De opgenomen onderzoeken waren grotendeels ongecontroleerd of van lage kwaliteit, de analyse was retrospectief, en een hoofdauteur was verbonden aan een ozonapparatenbedrijf, dus ligt het gepoolde cijfer boven de werkelijke sterkte van het bewijs.
De grote patiëntenaantallen zijn aantrekkelijk, maar ze zijn vooral afkomstig uit ongecontroleerde onderzoeken. Lees het resultaat voor de tussenwervelschijf als een voorlopig signaal, en weeg dit af tegen het gedocumenteerde, zij het zeldzame, risico op gasembolie door injectie nabij de wervelkolom, dat wordt behandeld in de voorzorgsmaatregelen.
The study · 1
Steppan et al., meta-analysis of ozone treatment for herniated lumbar discs · J Vasc Interv Radiol 2010;21(4):534-548
Joint And Arthritis Pain
In the same 59-person trial, ozone improved knee function, range of motion and six-minute walk distance
Alongside less pain, people in the trial moved a bit better: they walked further and got up and moving more easily than the control group.
The 2025 Adv Rheumatol randomized controlled trial (n=59, three arms: ozone 20 micrograms per milliliter, 40 micrograms per milliliter, and oxygen control) reported significant gains in functional-mobility measures for both ozone arms versus control, including the WOMAC function subscale, knee flexion range of motion, the Timed Up and Go test, and the six-minute walk test, with no significant difference between the two ozone concentrations. Follow-up was short and the sample was small.
The mobility gains ride alongside the pain result from one small trial. Treat them as an early signal worth watching, not a settled functional benefit, and keep loading exercise as the intervention with the strongest evidence for knee osteoarthritis function.
The study · 1
Arjmanddoust et al., two doses of intra-articular ozone therapy in knee osteoarthritis, double-blind RCT · Adv Rheumatol 2025;65(1):11
Counts once: this finding and 1 other here come from the same source, so they are one body of evidence, not separate confirmations.
Ozone matched hyaluronic acid for knee pain, with no difference across 424 patients
Head to head, ozone and hyaluronic acid knee injections gave about the same pain relief a few months out, with neither pulling ahead.
A 2024 level-I meta-analysis (Eur J Orthop Surg Traumatol) collected data on 424 patients (74 percent women, mean age 61) comparing intra-articular ozone with hyaluronic acid. Groups were matched on age, BMI and baseline patient-reported outcomes, and there was no significant difference in visual-analogue pain scores at four to six months (P = 0.4). The finding is that the two are comparable, not that either is inert.
If a clinic frames ozone as clearly better than the established hyaluronic-acid injection, the head-to-head evidence does not support that; they performed similarly in the pooled data.
The study · 1
Migliorini et al., intra-articular ozone versus hyaluronic acid for knee osteoarthritis, level I meta-analysis · Eur J Orthop Surg Traumatol 2024;35(1):20
Skin And Hair
Als aanvulling bij diabetische voetulcera halveerde ozon ongeveer het aantal amputaties (RR 0.46), maar sloot het niet meer ulcera
Bij diabetische voetulcera versnelde het toevoegen van ozon aan normale wondzorg de genezing en verlaagde het de kans op amputatie, maar het zorgde niet duidelijk voor meer volledig gesloten ulcera dan goede standaardzorg alleen.
Een systematische review en meta-analyse uit 2024 (Curr Pharm Des) van elf onderzoeken bij 960 patiënten vond dat ozon als aanvulling de gemiddelde genezingstijd en ziekenhuisopname significant verkortte en het amputatierisico verlaagde (RR 0.46, 95 procent BI 0.30 tot 0.71), terwijl het effect niet verschilde van standaardbehandeling voor volledige genezing van het ulcus. Een umbrella-review van meta-analyses uit 2026 kwam tot een voorzichtigere conclusie en vond dat ozon niet superieur was aan controle voor wondgenezing (RR 1.69, 95 procent BI 0.90 tot 3.17, het interval kruist geen effect). De heterogeniteit tussen onderzoeken is hoog.
De meest betrouwbare interpretatie is dat ozon mogelijk helpt als aanvulling op goede diabetische wondzorg, niet als vervanging ervan. Het signaal over amputatie verdient klinische aandacht, en het voordeel voor volledige genezing is niet vastgesteld.
The study · 1
Izadi et al., ozone therapy on diabetes-related foot ulcer outcomes, systematic review and meta-analysis · Curr Pharm Des 2024;30(27):2152-2166
Blood Sugar
In één onderzoek bij 101 patiënten verbeterde twintig dagen ozon de bloedsuiker- en antioxidantmarkers
Eén ouder onderzoek bij diabetespatiënten vond dat een ozonkuur bloedsuiker- en antioxidantmarkers in een gunstige richting duwde, maar het is één klein onderzoek.
Een gerandomiseerde gecontroleerde trial uit 2005 (Eur J Pharmacol) in Havana includeerde 101 patiënten met type 2-diabetes en neuro-infectieuze diabetische voet, waarbij één groep ozon kreeg via lokale en rectale insufflatie en de andere topische en systemische antibiotica gedurende twintig dagen. De ozongroep toonde verbeterde glykemische controle, voorkwam oxidatieve stress met genormaliseerde organische peroxiden, en verhoogde de activiteit van superoxide-dismutase. Het is één klein, kort, eencentrumonderzoek, niet op grote schaal gerepliceerd, en de metabole veranderingen zijn secundair aan een wondbehandelingsstudie, geen specifiek onderzoek naar glucosecontrole.
Dit is een voorlopig signaal uit één klein onderzoek, geen reden om ozon te overwegen voor bloedsuikercontrole. Benaderingen met veel sterker bewijs, zoals dieet, beweging en glucoseverlagende medicatie, blijven de betere keuze.
The study · 1
Martinez-Sanchez et al., therapeutic efficacy of ozone in patients with diabetic foot · Eur J Pharmacol 2005;523(1-3):151-161
How it works
Het idee van oxidatieve eustress: een lage ozondosis kan de Nrf2-antioxidantafweer inschakelen, een mechanisme, geen bewezen voordeel
Het idee achter ozon is een kleine, gecontroleerde dosis oxidatieve stress die het lichaam aanzet tot het verhogen van zijn eigen antioxidantafweer, en een vroeg onderzoek zag tekenen van die reactie.
De hormetische hypothese stelt dat een lage ozondosis een kortstondige, gecontroleerde oxidatieve stress (eustress) veroorzaakt die de Nrf2- en elektrofiel-responsief-element-route en downstream antioxidantenzymen opreguleert. Een voorlopig in-vivo-onderzoek uit 2014 (Eur J Pharmacol) bij gezonde vrijwilligers die drie grote autohemotherapiesessies kregen, rapporteerde bewijs dat ozonpreconditionering koppelde aan Nrf2- of EpRE-activatie. Dit is een plausibel, actief bestudeerd mechanisme, en een bewegende mechanistische marker stelt niet vast dat een klinische uitkomst verbetert. Dosis is cruciaal: hetzelfde molecuul dat bij lage concentratie een mild signaal geeft, is bij hogere concentraties een gif.
Lees het mechanisme als een hypothese die wordt onderzocht, niet als bewijs van voordeel. Een route die activeert in een laboratoriumonderzoek is waar de vraag begint; of ozon een bepaalde aandoening helpt, is wat een trial moet aantonen.
The study · 1
Re et al., is ozone pre-conditioning linked to the Nrf2/EpRE pathway in vivo, preliminary result · Eur J Pharmacol 2014;742:158-162
Evidence And Methods
De brede beweringen over ontgifting en chronische ziekten zijn niet vastgesteld; gepoolde onderzoeken bestrijken slechts vier aandoeningen
De verstrekkende beweringen dat ozon het lichaam ontgift of een breed scala aan chronische ziekten behandelt, worden niet ondersteund door het gepoolde onderzoeksbewijs, dat slechts een handvol specifieke aandoeningen bestrijkt en zelfs daar gemengd is.
Een umbrella-review uit 2026 (Med Sci, Basel) van systematische reviews met meta-analyses van gerandomiseerde onderzoeken vond slechts zeven meta-analyses die vier indicaties bestreken: chronische parodontitis (gemengd), COVID-19, diabetische voetulcera, en operaties aan geïmpacteerde verstandskiezen. Bij COVID-19 verlaagde ozon de PCR-positiviteit (RR 0.07), maar dit werd beoordeeld als een klinisch onbelangrijke surrogaatmaat, zonder voordeel voor ziekenhuisopname, IC-opname of sterfte. De zekerheid van bewijs volgens GRADE was over het algemeen laag. Niets in het beoordeelde bewijs ondersteunt systemische ontgifting, immuunversterking, of het breed behandelen van chronische ziekte, en sommige van dergelijke beweringen missen een plausibele fysiologische basis.
Wanneer een kliniek ozon aanbiedt voor een lange lijst niet-gerelateerde chronische aandoeningen of voor ontgifting, reikt het gepoolde bewijs niet tot die toepassingen. Vraag welke specifieke aandoening onderzoeksbewijs heeft, en met welke mate van zekerheid.
The study · 1
Cacciatore et al., effectiveness and safety of ozone therapy in humans, umbrella review · Med Sci (Basel) 2026;14(2):289
The Regulatory Position
Regulators treat ozone with unusual bluntness. The United States Food and Drug Administration states that ozone is a toxic gas with no known useful medical application in general medicine. The agency has acted against devices marketed to introduce ozone into the body.
That position sits alongside the specific trial evidence: a few local uses carry early signals, and the broad medical claims for ozone are not accepted by regulators. Anyone weighing ozone therapy is doing so as an option that lacks general regulatory approval.
Go Deeper
- IV vitamin drips and NAD therapy: another infusion category sold in storefronts, where the delivery is dramatic and the promise is far ahead of the controlled evidence.
- Hyperbaric oxygen: a different oxygen-based therapy, useful for seeing where a gas-delivery treatment has firm evidence for specific uses and where it does not.
- Arthritis: the joint condition where ozone has its strongest signal, set against the other options for knee pain.
- Low back pain: the wider picture for disc and back pain, into which the ozone discolysis evidence fits.
- Red light therapy: another device-based practice, useful for comparing how evidence and marketing diverge.
Cautions For This Practice
Everything to be aware of is here, in one place. This practice suits most healthy people; a few situations call for real care.
Het inademen van ozon bij slechts 0.07 ppm verminderde de longfunctie en veroorzaakte ontsteking van de luchtwegen bij 38 gezonde volwassenen
A 2026 double-blind randomized controlled human exposure study (Environ Res) exposed 38 healthy adults aged 19 to 34 to clean air and to 0.07 ppm ozone for 6.6 hours with intermittent moderate exercise, measuring pulmonary function before and after and neutrophils in sputum. Ozone at this low, regulatory-standard concentration produced decremental lung-function effects and airway inflammation. The authors note that controlled human exposure studies have consistently provided strong evidence of harmful respiratory effects of ozone, a body of work underpinning air-quality regulation. Clinical ozone routes are deliberately designed to keep the gas away from the airways for exactly this reason.Pennington et al., lung function and inflammation after 6.6 hours of 0.07 ppm ozone exposure
Injected ozone has caused gas embolism and multifocal stroke, in one case through a heart defect (patent foramen ovale)
Multiple case reports document serious gas-embolic events from ozone injection. A 2024 report (BMJ Neurol Open) describes a 58-year-old woman who developed multiple cerebral gas emboli and multifocal ischemic stroke during an intradiscal oxygen-ozone injection for disc herniation, with echocardiography revealing a patent foramen ovale as a route for paradoxical embolism. A further report describes multifocal stroke from ozone gas emboli following a cervical paravertebral ozone injection. These are individual cases, not pooled incidence, so they establish that the harm is real and can be severe, without fixing how often it happens.Khosravi and Mirzaasgari, cerebral gas embolism and multifocal ischemic stroke during oxygen-ozone therapyMultifocal stroke from ozone gas emboli, case report
Ozone autohemotherapy's safety record is too thin to quantify its true side-effect rate
A 2026 PRISMA-guided scoping review (Clin Exp Rheumatol) of oxygen-ozone autohemotherapy, focused on fibromyalgia, set out to catalog documented adverse events and stratify risk, and concluded that comprehensive safety data remain limited despite growing clinical interest. This is a statement about the state of the evidence, not a measured harm rate: the systemic route is used without a well-characterized adverse-event profile, which itself is a reason for caution and for treatment only in properly equipped settings.Casale et al., oxygen-ozone autohaemotherapy in fibromyalgia, safety profile and adverse events, scoping review
Inhaling ozone is harmful
Ozone is a respiratory toxin. Controlled human exposure shows that even at the low concentration allowed for outdoor air, breathing it reduces lung function and inflames the airways of healthy adults. No protocol treats inhalation as a route, and legitimate ozone practice is designed to keep the gas out of the breathing passages.
Gas embolism from injected ozone
Because ozone is delivered as a gas, injecting it can introduce bubbles into the bloodstream. Case reports describe cerebral gas embolism and multifocal stroke during intradiscal and neck ozone injection. In one case the bubble crossed through a patent foramen ovale, a common heart opening, to the arterial side. Injecting ozone into a vein is a separate and serious danger for the same reason.
Systemic routes have limited safety data
For autohemotherapy and other systemic routes, comprehensive adverse-event data remain limited, so the true risk profile is not well characterized even where the treatment is in use. Limited data leaves the true risk unknown; it does not show the route is safe. That gap is a reason for conservative use and for treatment only in a properly equipped setting.
Unregulated clinics and no general approval
Ozone therapy lacks general regulatory approval. Many treatments are offered in storefront or clinic settings outside standard medical checks, so dosing, sterile technique, screening, and emergency readiness are not guaranteed. Ask which specific use has trial evidence, and at what certainty.
Not a substitute for diagnosis or standard care
Reaching for ozone to treat a persistent condition can delay finding and treating the underlying cause. For anything serious or lasting, get a diagnosis and standard care first, then discuss any ozone use with your doctor.
Start slow, be smart, read the research, and consult a professional if you have any concerns. This is here to inform your choice, not make it for you.
Common Questions
Does ozone therapy work for anything?
For a small set of local uses, controlled trials show short-term benefit. A double-blind study in 59 people found an ozone knee injection lowered pain against an oxygen-only control, and pooled data on 960 patients tied ozone to fewer diabetic-foot amputations. Both bodies of evidence are small and mostly low quality. Nothing in the trials supports whole-body detox or a broad cure for chronic disease.
How is ozone therapy given?
By several routes that differ sharply in risk and evidence. A metered gas can be injected into a joint or near a spinal disc under imaging. In autohemotherapy, blood is drawn, mixed with ozone outside the body, and returned. Rectal insufflation delivers the gas mixture without a vein. Ozonated water and oil go onto skin and wounds. Each route carries its own evidence and its own risk, so the specific route and use matter more than a single verdict on ozone.
Is ozone therapy safe?
The answer depends almost entirely on the route. Breathing ozone harms the lungs, so inhalation is not a treatment route at all. Injected as a gas, ozone has led to gas embolism and stroke, with case reports during disc and neck injections. Injecting it into a vein is a separate and serious danger. Ozonated oil or water on the skin keeps the chemistry at the surface and is the gentlest option. For systemic routes such as autohemotherapy, safety data are limited, so the risk stays poorly mapped.
Does ozone detoxify the body or boost oxygen levels?
No. Ozone (O3) does not add measurable oxygen to the blood, and there is no established detox effect. What is under study is narrower: a brief, low-dose oxidative signal that may activate the body's antioxidant systems, led by the Nrf2 pathway. The cleanse framing goes well beyond that.
What does the FDA say about ozone therapy?
For ozone (O3) to kill germs, the Food and Drug Administration says, it must reach a concentration far higher than people or animals can safely tolerate. That is the agency's core objection to ozone as medicine. The FDA endorses none of the broad ozone cures sold to the public.
Explore Related
Other pages this one connects to, by the evidence they share, the outcomes they touch, and the ground they cover.
All 13 sources on this page independently checked and cross-referenced.
Thomas Dehli, Founder & Editor, Sacred Lotus
Sacred Lotus has published Chinese medicine reference material since 2001. Integrative pages are held to the same standard as the herb and formula library: cite the source, grade the claim at its real strength, and say where the research has not looked. This page is educational and it is not medical advice. Last reviewed and updated August 9, 2026.
Evidence strength
How confidently the research supports a claim. Strength describes the evidence, not our endorsement.