What are safe therapeutic doses of ivermectin for approved uses and how do they compare to doses people take recreationally?
Executive summary
Approved human ivermectin dosing for common parasitic indications is weight‑based and typically in the 150–200 micrograms per kilogram (mcg/kg) range as a single dose (for example, 0.15–0.2 mg/kg) [1] [2]. Public health authorities warn that some people take veterinary formulations or much higher “recreational” or experimental regimens (reports and case series describe doses up to 1–2 mg/kg or multi‑day courses), and taking large or animal products can cause harm; FDA and clinical reviews advise against unapproved high‑dose use for COVID‑19 or cancer [3] [4] [5] [6].
1. What “approved” ivermectin dosing looks like — short and specific
For FDA‑approved human uses and standard parasitic indications, ivermectin tablets are dosed by body weight and the usual single‑dose range clinicians use is about 150–200 mcg/kg (0.15–0.20 mg/kg) with repeat dosing only when specified by the indication (examples: repeated every 3–12 months for some infections) [1] [2] [7]. Sources restate the tablet strengths (3 mg commonly cited) and caution that dosing must be determined by a clinician [1] [2].
2. Why authorities caution about off‑label, higher dosing
Major public‑health bodies and drug regulators stress that ivermectin is not approved for viral infections such as COVID‑19 and that the safety and efficacy outside approved parasitic uses have not been established; the FDA specifically warns that taking large doses and using animal formulations is dangerous because those products are different and untested in humans [3] [4]. Clinical guideline reviews note that in vitro antiviral levels would require plasma concentrations far above approved dosing — in some pharmacokinetic estimates, up to 100‑fold higher — which explains both the interest and the safety concern for large doses [4].
3. What people actually take recreationally or experimentally
Reporting, case compilations and social media–driven communities document people taking ivermectin at far higher doses or for prolonged regimens: anecdotes and compilations reference regimens of roughly 1 mg/kg/day or multi‑day high‑dose schedules, and some case report aggregators describe claimed protocols of 1–2 mg/kg — many times the approved single‑dose range [8] [6] [9]. These sources are primarily compilations, testimonials and non‑regulatory reports rather than randomized controlled evidence [8] [6].
4. Evidence on harms from inappropriate dosing
Clinical surveillance and case series recorded toxic effects after people self‑medicated, with increased calls and hospitalizations tied to use of veterinary products or high single doses; one NEJM communication documented patients who used veterinary ivermectin and developed symptoms within hours after large, first‑time doses [5]. FDA and MedlinePlus explicitly warn that animal formulations differ and can be dangerous for humans [3] [10].
5. Conflicting narratives: clinical trials, reviews, and anecdote
Some small trials and observational reports showed signals (e.g., a 72‑patient trial reported faster viral clearance for a five‑day ivermectin arm), and proponents point to case series and reviews arguing potential benefit or safety at various doses [11] [12]. Yet major guideline panels and regulatory statements conclude randomized‑trial evidence does not show a clear clinical benefit for COVID‑19 and recommend against routine use outside trials; they also highlight pharmacologic reasons that in‑vitro antiviral findings do not translate to safe, achievable human dosing [4] [5].
6. How to compare numbers — a practical example
A 60‑kg adult at a standard antiparasitic dose (0.15 mg/kg) would take about 9 mg once; at 0.2 mg/kg about 12 mg once — in practice that’s several 3 mg tablets and determined by a clinician [1] [2]. By contrast, reported experimental or anecdotal regimens of 1 mg/kg/day for several days would be roughly five to seven times higher per day (60 mg/day for a 60‑kg person), and case compilations cite even higher cumulative exposures [8] [6].
7. What reporting leaves unsaid and limitations
High‑dose protocols in the public domain are mostly testimonial, social‑media driven, or collected in non‑peer‑reviewed compilations; controlled safety data for large, repeated human doses remain limited in the mainstream clinical literature cited here [8] [6]. Regulatory warnings and guideline recommendations are explicit about this evidence gap and emphasize not using animal products or exceeding approved doses [3] [4].
8. Bottom line and advice from cited authorities
Stick to clinician‑prescribed, weight‑based doses for approved parasitic indications (about 150–200 mcg/kg) and heed FDA and guideline warnings: do not self‑treat with veterinary ivermectin or high‑dose off‑label regimens; reports of higher‑dose use are primarily anecdotal and carry documented risk [1] [3] [4] [5]. Available sources do not mention a safe, approved human dosing schedule for COVID‑19 or cancer; such uses remain investigational [4] [6].