What clinical trials have evaluated ivermectin for COVID-19 and what were their results?

1. What was tested: dozens of trials, many designs

Researchers registered and ran more than 60–75 ivermectin trials around the world, covering prophylaxis and treatment in outpatients and inpatients, using varied doses and schedules; many small randomized controlled trials (RCTs), some larger platform trials, and multiple observational reports comprise the literature ^{[7] [8] [3]}.

2. Systematic reviews: mixed signals, low certainty overall

A 2021–2022 systematic review and meta‑analysis summarized results across many studies and found signals that ivermectin might reduce viral load, progression, or deaths in some pooled analyses but judged certainty low to very low because trials were small, heterogeneous and at risk of bias; authors warned that moderate‑certainty claims of large mortality reductions were possible but not definitive ^{[3] [9]}.

3. Large randomized trials and platform studies reached different conclusions

Well‑designed, larger randomized trials did not confirm clinically meaningful benefit. The adaptive platform trial reported in NEJM randomized symptomatic outpatients to ivermectin (400 µg/kg daily for 3 days) versus placebo and found no clear reduction in the composite endpoint of hospitalization or extended emergency observation ^[4]. The Brazil‑based TOGETHER platform and related arms tested ivermectin among other drugs and concluded ivermectin did not reduce hospital admission or prolonged emergency observation in outpatients ^{[5] [6]}.

4. Regulators and guideline groups weigh the total evidence and restrict use

Global public‑health bodies recommend caution: WHO advised ivermectin only be used within clinical trials because pooled evidence (16 RCTs, 2,407 participants in WHO’s review) was of “very low certainty” for mortality and other clinical endpoints ^[1]. The European Medicines Agency also advised against using ivermectin for COVID‑19 outside randomized trials, noting most studies were small with limitations and heterogeneous dosing ^[2].

5. Conflicting meta‑analyses, credibility problems and retractions

Some advocacy groups and meta‑analyses have reported large effects favoring ivermectin, but independent reviewers and journalists have flagged methodological flaws, conflicts of interest and withdrawn or questioned studies in the ivermectin literature; several trials have been small, non‑randomized, or later retracted/criticized, reducing confidence in pooled positive signals ^{[3] [6] [10]}.

6. Ongoing trials and unanswered questions

Despite many completed studies, investigators continued to register and run trials (including large NIH‑sponsored platforms such as ACTIV‑6), and registries still list prophylaxis and treatment trials into 2024–2025, reflecting remaining uncertainties about dosing, timing, and subgroups — but not a presumption of benefit ^{[11] [12]}.

7. What the balance of evidence supports now

Available systematic reviews, regulatory guidance and the results of larger randomized trials converge on the conclusion that evidence is insufficient to support routine ivermectin use for prevention or treatment of COVID‑19 outside clinical trials; randomized, well‑powered trials have failed to show clear clinical benefit, and guideline panels rate existing evidence as low or very low certainty ^{[1] [4] [3]}.

Limitations and context: reporting and meta‑analyses differ because of trial quality, small sample sizes, heterogeneous dosing and some discredited studies; sources disagree on the magnitude of possible effects, and proponents cite pooled positive meta‑analyses while WHO, EMA and large RCTs emphasize uncertainty or null findings ^{[3] [1] [2]}. Available sources do not mention every individual trial by name; for full trial‑level extraction consult trial registries and the cited reviews ^{[8] [9]}.