Ivermectin dosage guide: Form, strength, when to take, and more

Important: This article is for general education, not personal medical advice. Ivermectin is prescription-only for humans in the U.S., and the “right dose” depends on the infection, your weight, and your medical history. If you’re tempted to self-dose, please don’tthis is one of those meds where “close enough” is not a vibe.

Quick overview (what ivermectin is and what it isn’t)

Ivermectin is an antiparasitic medication used to treat certain infections caused by parasites. In the U.S., oral ivermectin tablets are FDA-approved for specific parasitic infections (notably strongyloidiasis and onchocerciasis). It also exists in topical forms for different conditionslike rosacea (cream) and head lice (lotion).

One big clarification: ivermectin is not authorized or approved by the FDA to prevent or treat COVID-19. So there’s no legitimate “COVID dose” to sharebecause it’s not an approved use, and taking high or inappropriate doses can be harmful.

Forms and strengths

1) Oral tablets (human prescription)

• Common strength: 3 mg tablets (often referenced as “3-milligram tablets”).
• How dosing works: typically calculated by micrograms per kilogram (mcg/kg) of body weight for certain infections.

2) Topical cream for rosacea

• Strength: ivermectin 1% cream (often labeled as 10 mg/g).
• Use: inflammatory lesions of rosacea.

3) Topical lotion for head lice

• Strength: ivermectin 0.5% lotion.
• Use: head lice treatment (typically single application in many patients).

4) What not to use

There are veterinary formulations (pastes, injectables, “pour-ons”) meant for animals. These are not interchangeable with human prescriptions. Using animal products can lead to dosing errors and serious side effects. If it came from a feed store, it does not belong in your body.

What ivermectin treats (approved vs. commonly used off-label)

FDA-approved oral uses (U.S.)

• Strongyloidiasis (intestinal infection caused by Strongyloides stercoralis)
• Onchocerciasis (river blindness, caused by Onchocerca volvulus)

Common non-tablet uses (U.S.)

• Rosacea: topical ivermectin 1% cream
• Head lice: topical ivermectin 0.5% lotion

Off-label uses (provider-directed)

Clinicians sometimes prescribe oral ivermectin for conditions where it is not FDA-approved (for example, certain scabies cases). Off-label prescribing can be appropriate, but it should be guided by a licensed clinician who can weigh benefits, risks, and alternatives for your situation.

How ivermectin dosing is determined (and why weight matters)

For oral ivermectin, dosing for many parasitic infections is written as mcg/kg. That means two people taking ivermectin for the same infection may not take the same number of tabletsbecause body weight changes the dose.

Also, some conditions require repeat dosing because ivermectin may not reliably kill parasite eggs (or because it targets certain life stages). Translation: one-and-done isn’t always enough, even when you “feel fine.”

Oral ivermectin dosage (FDA-approved indications)

Do not use this section to self-prescribe. This is a reference-style overview of labeling and commonly cited clinical guidance so you understand what your prescriber may be doing.

1) Strongyloidiasis (intestinal)

Typical labeled approach: a single oral dose designed to provide approximately 200 mcg/kg. Patients are often instructed to take tablets on an empty stomach with water.

Follow-up matters: Some guidance recommends follow-up stool testing to confirm eradication. If larvae reappear, your clinician may recommend retreatment.

Clinical nuance: In real-world practice, some clinicians use 200 mcg/kg for 1–2 days for uncomplicated strongyloidiasis, depending on clinical context and guidelines. Severe cases (hyperinfection or disseminated disease) are medical emergencies and typically require specialist managementoften with daily therapy and intensive monitoring in a hospital setting.

2) Onchocerciasis (river blindness)

Typical labeled approach: a single oral dose designed to provide approximately 150 mcg/kg, often taken on an empty stomach with water.

Repeat dosing: Some patients may need additional doses months later to control infection, depending on clinical response and medical guidance.

Off-label spotlight: oral ivermectin for scabies (what people hear vs. what clinicians do)

Scabies is a common reason people search for “ivermectin dosage,” so let’s address it clearly:

• Oral ivermectin is not FDA-approved for scabies in the U.S.
• However, U.S. public health guidance notes that oral ivermectin can be used in certain scenarios.
• A commonly cited regimen for classic scabies is 200 mcg/kg per dose taken in two doses, each 7–14 days apart.

Timing twist: For scabies, some clinical guidance specifies taking ivermectin with food. That’s different from the “empty stomach” instructions often used for the FDA-labeled tablet indications. The takeaway is simple: follow the directions your clinician gives for your specific diagnosis, even when they differ from what you read elsewhere.

Topical ivermectin dosing (rosacea and head lice)

Ivermectin 1% cream for rosacea

Typical use: apply to affected facial areas once daily. Many product instructions describe using small “pea-size” amounts for different parts of the face (forehead, chin, nose, each cheek) and spreading a thin layer while avoiding eyes and lips.

Realistic expectation: rosacea treatment is usually measured in weeks, not days. Consistency tends to matter more than applying “extra,” which can irritate skin.

Ivermectin 0.5% lotion for head lice

Typical use: applied to dry hair and scalp, left on for a set amount of time (often 10 minutes in product instructions), then rinsed off with water. Many references describe it as a single application treatment in most patients and note that nit combing may not be required.

Retreatment: some guidance cautions against repeating treatment without consulting a healthcare provider.

When to take ivermectin (timing, food, and practical tips)

Oral tablets: empty stomach vs. with food

• Empty stomach with water is commonly specified for the FDA-labeled oral tablet indications (like strongyloidiasis and onchocerciasis).
• With food may be recommended in certain off-label protocols (notably some scabies guidance).

If your instructions say “empty stomach,” that typically means taking it at least 30–60 minutes before food (or a couple hours after a meal). When in doubt, ask your pharmacistthis is literally their favorite kind of question.

Missed dose (oral ivermectin)

Oral ivermectin is often given as a single dose (or a small number of doses). If you miss a dose in a multi-dose plan, contact your prescriber for the best timing rather than doubling up on your own.

Who should be extra cautious (or avoid ivermectin unless a clinician says otherwise)

• Children under 15 kg: safety may not be established for some uses and guidelines.
• Pregnancy: safety is not established for certain indications; decisions should be clinician-guided.
• Breastfeeding: discuss risk/benefit with your clinician.
• Potential Loa loa exposure: travelers or people from regions where Loa loa occurs may need special evaluation due to risk of serious reactions.
• Significant liver disease or complex medication regimens: may need additional monitoring.

Side effects and what “normal” can look like

Many people tolerate ivermectin well at prescribed doses, but side effects can happen. Commonly reported effects include:

• Headache
• Dizziness
• Nausea or diarrhea
• Skin rash or itching

Important nuance: In some parasitic infections (like onchocerciasis), symptoms can also come from the immune response to dying parasites, not just the medication itself. That’s one reason clinicians may advise monitoringespecially if you have heavy parasite burden or eye involvement.

When to seek urgent help

Seek urgent care for severe allergic reactions (trouble breathing, facial swelling, widespread hives), severe neurologic symptoms (confusion, seizures), or symptoms that feel rapidly worsening after dosing.

Drug interactions (and why your medication list matters)

Ivermectin can interact with other medications. The specific risk depends on your full medication list, supplements included. A few reasons clinicians and pharmacists may ask extra questions:

• Some drugs can increase ivermectin levels via metabolism/transport effects.
• Blood thinners (like warfarin) may require closer monitoring in some patients.
• Combining multiple medications that cause dizziness can raise fall risk.

Bring a current medication list to your appointmentor at least a photo of your pill bottles. “It’s the small white one” is honest, but not actionable.

Storage and handling

• Store medications at room temperature, away from excessive heat and moisture.
• Keep out of reach of children and pets.
• For topical products: avoid contact with eyes, and follow label directions carefully.

FAQs

Is ivermectin a one-time dose?

Sometimes. Some indications use a single dose; others may require repeat dosing weeks later or months later. Your diagnosis determines the scheduleyour calendar doesn’t get to vote.

Why does my friend’s dose look different from mine?

Two major reasons: (1) body weight changes dose when dosing is mcg/kg, and (2) different infections have different dosing targets and timing.

Can I take ivermectin “just in case” after travel?

That’s not recommended. Treatment decisions typically depend on symptoms, exposure risk, and diagnostic testing. Taking antiparasitics without a clear indication increases the chance of side effects and can delay correct diagnosis if symptoms persist.

Is there a recommended dose for COVID-19?

No. The FDA has not authorized or approved ivermectin to prevent or treat COVID-19. Using ivermectin for that purposeespecially at high dosescan be dangerous.

Real-world experiences and practical lessons (extra section)

This section shares common experiences people report in clinical settings and typical “what it felt like” patterns. These are not personal stories and shouldn’t replace medical advice.

Experience #1: “My doctor said weight-based dosingwhy can’t I just take a fixed number?”

A common moment of surprise happens when someone picks up a prescription and sees directions like “take 4 tablets once” while their partner’s label says “take 5 tablets once.” For oral ivermectin, this is often totally normal because many dosing approaches are based on mcg/kg. People tend to expect antibiotics-style dosing (“one pill twice a day”), but ivermectin’s labeled tablet dosing for certain infections doesn’t work like that. In practice, clinicians often double-check weight, round to available tablet sizes, and choose a regimen that matches the infection being treated. Patients often say this feels “too few pills” for something that sounds seriousyet for some infections, a properly calculated single dose can be effective.

Experience #2: “I took it and felt itchydoes that mean I’m allergic?”

Itching can be confusing because it can be a symptom of the infection, a side effect, or an immune response as parasites die. Some people describe a brief flare of skin symptoms after treatment, especially with certain parasitic infections. Clinicians often look at the timing, whether there’s swelling or breathing trouble, and whether the rash is localized or widespread. The practical lesson many patients learn: if you have mild, expected side effects, you still want to report thembut emergency symptoms (like trouble breathing, severe swelling, or neurologic changes) should be treated as urgent.

Experience #3: “Scabies is gone… but I’m still itchy. Did the medicine fail?”

With scabies, lingering itch can persist even after mites are eliminatedsometimes for weeks. People often interpret ongoing itch as “treatment didn’t work,” but clinicians may call this post-scabies itch or dermatitis, which can improve gradually. Another common experience is frustration with the environmental and household steps: washing bedding, treating close contacts, and cleaning shared fabrics. In many households, the “real cure” is getting everyone treated and the home routine handled at the same time. Patients often say the logistics were harder than taking the medication itself.

Experience #4: “Head lice treatment felt simplewhy was my pharmacist so strict about instructions?”

For topical ivermectin lotion, people frequently report that the process feels refreshingly straightforward: apply to dry hair, wait the recommended time, rinse. Where things go sideways is when instructions aren’t followed (not using enough product to coat, rinsing too early, or immediately shampooing when the label says to wait). Another common theme: families often want to repeat treatment “just to be safe,” but guidance may advise against retreatment without a provider’s input. The lesson: with lice, the product can be effective, but the timing and technique are the difference between “done in one” and “why are we still dealing with this?”

Experience #5: “I bought ivermectin online because it was faster.”

This is where clinicians get genuinely worried. People who self-source ivermectinespecially non-prescription productsoften don’t realize how easy it is to take the wrong dose, use the wrong formulation, or miss the actual diagnosis. Patients sometimes report side effects like dizziness, nausea, diarrhea, or feeling “foggy,” and later learn they took a product not intended for humans or took much more than recommended. A recurring clinical message is blunt but caring: getting a correct diagnosis (and a legitimate prescription when appropriate) is safer than trying to DIY your way through parasites. When symptoms persist, self-treatment can delay proper testing, which can matter a lot for infections like strongyloidiasisespecially in people with weakened immune systems.

Experience #6: “The biggest relief was having a plan.”

Across conditions, many patients describe the biggest stress as uncertainty: How many doses? When do I repeat it? Do I need follow-up tests? What should my family do? The most helpful thing is often a written plan from a clinician or pharmacist: dose timing, whether to take it with food or on an empty stomach, what side effects to watch for, and what follow-up is needed. When people have that checklist, anxiety dropsand adherence improves. In other words, the best “hack” isn’t a secret dose; it’s clarity.

Conclusion

Ivermectin comes in different forms (oral tablets, topical cream, topical lotion), and dosing varies widely depending on the condition being treated. For FDA-approved oral uses, dosing is typically weight-based, and timing may involve taking it on an empty stomach with water. For other clinician-directed uses (like some scabies regimens), instructions may differsometimes even recommending dosing with food. The safest approach is simple: use ivermectin only as prescribed, avoid veterinary or unverified products, and follow your clinician’s exact directions for timing, repeat doses, and follow-up.