How does the dosage of ivermectin for horses compare to the recommended human dose?
Executive summary
Human ivermectin dosing for approved parasitic infections is weight‑based and typically measured in micrograms per kilogram; common human regimens are far lower than horse products, which are formulated for animals weighing up to ~1,250 lb and dosed at about 91 mcg per lb (≈200 mcg/kg) for horses [1]. Retail horse pastes are concentrated (1.87% paste = 18.7 mg/g) and packaged so one syringe treats a large animal; manufacturers and regulators explicitly warn these products are not for human use [2] [1] [3].
1. How approved human doses compare to horse paste dosages — a straight number check
Medical guidance and dosing tables for humans show ivermectin dosing depends on the condition and body weight; standard single‑dose regimens used for some human parasitic infections are typically in the range of micrograms per kilogram rather than milligrams per kilogram used for animals, and authoritative medical summaries note dosing is weight‑based for humans [4]. By contrast, many horse paste labels state a recommended equine dose around 91 mcg per lb (which equals about 200 mcg/kg) and packaging is sized to treat a 1,250 lb horse in a single syringe [1].
2. Product formulation and labeling — built for different species and safety rules
Manufacturers of horse ivermectin paste make explicit claims that their product is formulated and approved for equine use only and “has not been tested in humans and is not approved for use with humans” [3]. Retail descriptions repeat that these products are not intended for human consumption and include formulation details (1.87% paste = 18.7 mg/g) and dosing rings to set doses by horse weight [2] [1].
3. Regulatory and safety context — FDA and clinical evidence
The FDA has stated ivermectin is approved for certain human parasitic infections at specified doses and forms, and that currently available clinical trial data do not support ivermectin for indications such as COVID‑19; the agency warns that taking large doses can be dangerous and that animal products differ from human‑approved medicines [5]. Available sources do not mention specific human‑prescription mg/kg numbers on the FDA page, but they emphasize that human products and veterinary products are distinct and that humans should not use animal formulations [5].
4. Why people sometimes compare horse and human doses — and the risk of misuse
Horse syringes are calibrated to deliver a dose for a 1,000+ lb animal in one application; sellers and some industry commentary warn that a few milligrams too much for a human can cause side effects such as dizziness or nausea, and that animal formulations may include inactive ingredients not tested for human safety [6] [1]. Retail and manufacturer warnings stress that dosing must be by weight and that under‑ or overdosing has consequences for animals (parasite resistance) and for safety in unintended species [2] [3].
5. Conflicting messages and why context matters in public discussion
There are two competing messages present in the materials: clinical and regulatory sources caution that human dosing is specific, approved human formulations exist, and clinical trials don’t support some off‑label COVID‑19 uses [4] [5]; commercial or informational sources addressing public demand explain differences between “human‑grade” and veterinary ivermectin and highlight overdose risks from using horse products in people [6]. The materials converge on the point that veterinary ivermectin is not tested or approved for human use [3], but differ in tone—regulatory sources emphasize evidence and safety [5], while some commercial blogs emphasize market access and product distinctions [6].
6. Practical takeaways — what the numbers and labels mean for an individual
If you compare the commonly quoted equine dose (~91 mcg/lb; ≈200 mcg/kg) used in horse pastes to typical human prescription regimens, horse dosing is expressed per‑weight but packaged to deliver hundreds to thousands of times the dose intended for a typical person when taken as a whole syringe; manufacturers and retailers explicitly instruct that those products are not for humans [1] [3]. For any human use of ivermectin, rely on a licensed clinician prescribing approved human formulations and doses described in medical references [4] [5].
Limitations and gaps: available sources do not provide a single, definitive table in these search results listing exact mg/kg values for every approved human indication, nor do they list precise comparative milligram totals for every marketed horse syringe size; my summary uses the available label figures and medical dosing principles reported above [4] [2] [1] [3] [5].