Front Line Doctors Ivermectin Protocol for Prevention and Treatment of COVID-19 (2023)

The Front Line COVID-19 Critical Care (FLCCC) Alliance was initially formed as a working group during the early COVID-19 pandemic days in response to multiple early reports of COVID patients with an inexplicably high need for prolonged mechanical ventilation and an excessive death rate. 

Based on rapidly emerging clinical trials evidence, the FLCCC team has developed the I-MASK+ protocol (is now divided into I-Prevent and I-Care protocols) for prophylaxis and at home treatment of early stage COVID-19. Quercetin, zinc and a number of nutrients and drugs are part of this protocol, not only for critical care but also for prophylaxis and mild disease being treated at home. This article, we will dive deeper to provide the scientific background, related references and rationale of the FLCCC protocols.

I-CARE COVID Treatment Protocol for Outpatients

FLCCC (Front Line COVID-19 Critical Care) Protocols

I-MASK+ Prevention & Early Outpatient Treatment Protocol for COVID-19 was designed for use as a prevention and in early outpatient treatment, for those who test positive for COVID-19. Component nutrients include vitamin D, C, melatonin, quercetin and zinc.

All the component medicines are FDA-approved (except ivermectin), inexpensive, readily available and have been used for decades with well-established safety profiles.

Please take note that I-MASK+ protocols are now:


As rates of infection with influenza and RSV rose in fall/winter 2022, FLCCC adapted the I-PREVENT protocol to include prevention against these viruses. The interventions recommended are likely to reduce the risk and severity of infection with COVID-19, influenza, and RSV infections as well as the common cold. It should be noted that the medications included in the I-PREVENT protocol are inexpensive, safe, and widely available. This protocol includes a section for pre-exposure (long-term) as well as a post-exposure (acute, short-term).

Note that there are two I-Prevent Protocols; the I-Prevent Covid protocol to prevent Covid and the I-Prevent Post vaccine protocol to prevent vaccine injury.

How to prevent infection before you’ve been exposed (Pre-exposure)

  • Antiseptic antimicrobial mouthwash: gargle twice daily (do not swallow). Choose mouthwashes containing chlorhexidine, povidone-iodine or cetylpyridinium chloride (e.g., Scope, Act, Crest).
  • Vitamin D: dosing varies; optimal target is greater than 50 ng/ml (Table 1) presents a safe and practical treatment schedule for raising serum concentrations in non-urgent situations. The dosing schedule illustrated in Table 2 should be used when recent serum concentration levels are unavailable.
  • Vitamin C (Liposomal preferred): 500 mg twice daily
  • Zinc: 20-50 mg/day
  • Commercial zinc supplements are commonly formulated as zinc oxide or salts with acetate, gluconate, and sulfate.
  • Melatonin: 1-6 mg nightly (slow/extended)
  • Begin with 1 mg and increase as tolerated to 6 mg at night. Causes drowsiness. Some patients are intolerant to melatonin, having very disturbing and vivid dreams; in these patients, it may be best to start with a 0.3 mg slow-release tablet and increase slowly, as tolerated.
  • Elderberry syrup, supplements or gummies: follow manufacturer’s dosing recommendations
  • Take during periods of high transmission of COVID-19, influenza, and RSV. A triple combination containing elderberry, Vitamin C, and zinc may be a convenient approach. Patients with autoimmune disease should take for 2 weeks or less and monitor their symptoms closely.
  • Resveratrol or a Combination Flavonoid supplement: 400-500 mg daily
  • The safety of resveratrol, quercetin, and pterostilbene has not been determined in pregnancy and they should therefore be avoided. Due to the possible drug interaction between quercetin and ivermectin, these drugs should not be taken simultaneously (i.e., should be staggered morning and night).
  • Ivermectin: In the current situation of abundant natural immunity along with the recent circulation of less severe and more highly transmissible variants, chronic weekly or Twice weekly ivermectin prophylaxis is no longer applicable to most people. The following prophylaxis approaches with ivermectin can be considered and applied based on patient preference, comorbid status, immune status, and in discussion with their provider:
    • Twice weekly ivermectin at 0.2mg/kg; can be considered in those with significant comorbidity and lack of natural immunity or immunosuppressive states or those with long COVID or post-vaccine syndrome who are not already on ivermectin as treatment
    • Daily ivermectin just prior to and during periods of high possible exposure such as travel, weddings, conferences, etc.
    • Immediate initiation of daily ivermectin at treatment doses (0.4mg/kg) upon first symptoms of a viral syndrome

Table 1. Guidance on Upfront Loading Dose Regimens to Replenish Vitamin D Stores in the Body

When serum vitamin D levels are available, the doses provided in this table can be used for the longer-term maintenance of serum 25(OH)D concentration above 50 ng/mL (125 nmol/L). The table provides the initial bolus dose, weekly dose, frequency, and the duration of administration of oral vitamin D in non-emergency situations, in a non-obese, 70 kg adult. *

* A suitable daily or weekly maintenance dose to be started after completing the loading-dose schedule. The dose should be adjusted for those who are overweight (higher) or underweight (lower).
** To convert ng/mL to nmol/L, multiply the amount in ng by 2.5; One µg = 40 IU.
$ Mentioned replacement doses can be taken as single, cumulative doses, two to three times a week spread out over a few weeks.
$$ From the day one of week two onwards.
# Estimated total Vitamin D dose needed to replenish the body stores (i.e., the deficit) is provided in the last column.

(Table adapted with permission from S.J. Wimalawansa)

Table 2. Vitamin D Dosing in the Absence of a Baseline Vitamin D Level

Longer-term maintenance schedules of oral vitamin D based on body weight to maintain the levels above 50 ng/mL (125 nmol/L) when the serum 25(OH)D concentrations are unknown.

* Example of a daily or once-a-week dose range for adults with specific body types (based on BMI for white Caucasians and body weight for other ethnic groups). Appropriate dose reductions are necessary for children.
# For those with chronic comorbid conditions, such as hypertension, diabetes, asthma, COPD, CKD, depression, and osteoporosis, and to reduce all-cause mortality, higher doses of vitamin D are needed. For them, one can use the doses that are recommended for persons with obesity (BMI, 30–39: the third row).
$ Those with multiple sclerosis, cancer, migraine headaches, and psoriasis, and those routinely taking medications such as anti-epileptic and anti-retroviral agents that significantly increase the catabolism of vitamin D should consider taking age-appropriate doses recommended for those with morbid obesity (BMI ≥ 40; the higher end of the daily doses in the fourth row).

(Table adapted with permission from S.J. Wimalawansa)

How to prevent infection if you have potentially been exposed (Post-exposure)

  • Naso-Oropharyngeal hygiene (Nasal Spray and Mouthwash): 2-3 times daily
  • The combination of nasal antiseptic sprays and oropharyngeal mouthwashes is strongly suggested. Choose a nasal spray with 1% povidone-iodine (for example Immune Mist™, CofixRX™ or Ionovo™) and mouthwashes containing chlorhexidine, povidone-iodine or cetylpyridinium chloride (e.g., Scope, Act, Crest).
  • Elderberry: four times daily as per manufacturer’s directions for 1 week (gummy, supplement, or syrup)
  • Vitamin C (Liposomal preferred): 500-1000 mg four times daily for 1 week
  • Elemental Zinc (Zinc lozenges preferred): 50-90 mg daily for 1 week
  • Melatonin: 2-5 mg at night (slow/extended release)
  • Resveratrol/Combination Flavonoid supplement: 500 mg twice daily
  • A flavonoid combination containing resveratrol, quercetin and pterostilbene is recommended.
Optional with documented exposure to COVID-19 (positive test):
  • Ivermectin: 0.4 mg/kg immediately, then repeat second dose in 24 hours;
  • Hydroxychloroquine (HCQ): 200 mg twice a day for 5 days.
  • Nitazoxanide: 500-600 mg twice daily for 5 days

Table 3. How to calculate ivermectin dose

Note that ivermectin is available in different strengths (e.g., 3, 6 or 12 mg) and administration forms (tablets, capsules, drops, etc.). Note that tablets can be halved for more accurate dosing, while capsules cannot.

ivermectin dosage by weight



Note that there are two I-Care Protocols; the I-Care Covid protocol (this article) to treat Covid and another protocol, I-Care Flu protocol; to treat influenza and RSV infections.

The I-Care protocol has been updated and below is their latest version (March 30, 2023). 

First Line Therapies

(In order of priority; not all required.)

  • Ivermectin: 0.4 to 0.6 mg/kg – one dose daily for at least 5 days or until symptoms resolve. If symptoms persist longer than 5 days, consult a healthcare provider. See Table 1 (below) for help with calculating correct dose. Due to a possible interaction between quercetin and ivermectin, these drugs should be staggered throughout the day (see Table 2 below). For COVID treatment, ivermectin is best taken with a meal or just following a meal, for greater absorption.
  • Hydroxychloroquine (HCQ): 200 mg twice a day for 5 to 10 days. Best taken with zinc. HCQ may be taken in place of, or together with, ivermectin. While ivermectin should be avoided in pregnancy, the FDA considers HCQ safe in pregnancy. Given the pathway used by the Omicron variant to gain cell entry, HCQ may be the preferred drug for this variant.
  • Mouthwash: 3 times a day. Gargle three times a day (do not swallow) with an antiseptic-antimicrobial mouthwash containing chlorhexidine, povidone-iodine or cetylpyridinium chloride (e.g., Scope, Act, Crest).
  • Nasal spray with 1% povidone-iodine: 2-3 times a day. Do not use for more than 5 days in pregnancy. If 1% product is not available, dilute the more widely available 10% solution (see box) and apply 4-5 drops to each nostril every 4 hours.
    • Pour 1 ½ tablespoons (25 ml) of 10% povidone-iodine solution into a 250 ml nasal irrigation bottle.
    • Fill bottle to top with distilled, sterile, or previously boiled water.
    • To use: tilt head back, apply 4-5 drops to each nostril. Keep head tilted for a few minutes, then let drain.
  • Quercetin (or a mixed flavonoid supplement): 250-500 mg twice a day. Due to a possible interaction between quercetin and ivermectin, these drugs should not be taken simultaneously (i.e., should be staggered at different times of day.) As supplemental quercetin has poor solubility and low oral absorption, lecithin-based and nanoparticle formulations are preferred.
  • Nigella sativa: If using seeds, take 80 mg/kg once a day (or 400 to 500 mg of encapsulated oil twice a day).
  • Honey: 1 g/kg one to two times a day.
  • Melatonin: 5-10 mg before bedtime (causes drowsiness). Slow- or extended-release formulations preferred.
  • Curcumin (turmeric): 500 mg twice a day. Curcumin has low solubility in water and is poorly absorbed by the body; consequently, it is traditionally taken with full fat milk and black pepper, which enhance its absorption.
  • Zinc: 75-100 mg daily. Take with HCQ. Zinc supplements come in various forms (e.g., zinc sulfate, zinc citrate and zinc gluconate).
  • Aspirin: 325 mg daily (unless contraindicated).
  • Kefir and/or Bifidobacterium Probiotics. Depending on the brand, these products can be very high in sugar, which promotes inflammation. Look for brands without added sugar or fruit jellies and choose products with more than one strain of lactobacillus and bifidobacteria. Try to choose probiotics that are also gluten-free, casein-free and soy-free.
  • Vitamin C: 500-1000 mg twice a day.
  • Home pulse oximeter. Monitoring of oxygen saturation is recommended in symptomatic patients, due to asymptomatic hypoxia. Take multiple readings over the course of the day and regard any downward trend as ominous. Baseline or ambulatory desaturation under 94% should prompt consultation with primary or telehealth provider, or evaluation in an emergency room. (See box for further guidance.)
    • Only accept values associated with a strong pulse signal
    • Observe readings for 30–60 seconds to identify the most common value
    • Warm up extremities prior to taking a measurement
    • Use the middle or ring finger
    • Remove nail polish from the finger on which measurements are made

Second Line Therapies

(In order of priority/importance.)

Add to first line therapies above if: 1) more than 5 days of symptoms; 2) poor response to first line agents; 3) significant comorbidities).

  • Nitazoxanide (NTZ): 500 mg twice a day for 5 days.

  • Vitamin D3: For patients with acute COVID-19 infection, calcifediol as dosed in table below is suggested.

  • B complex vitamins.

  • Fluvoxamine: 25-50 mg twice a day for 1 week.
    NOTE: Due to serious risks of acute anxiety that may progress to mania or suicidal/violent behavior, this drug should not be prescribed for COVID for longer than two weeks.

  • N-acetyl cysteine (NAC): 600-1200 mg orally twice a day.

  • Omega-3 fatty acids: 4 g daily.
    Vascepa (Ethyl eicosapentaenoic acid); Lovaza (EPA/DHA); or alternative DHA/EPA. Vascepa and Lovaza tablets must be swallowed and cannot be crushed, dissolved, or chewed.

Treatment of BA.4/BA.5/BQ.1.1 and XBB1 Variants

Treatment of Current Circulating Omicron variants

Limited data are available on the clinical implications of the current circulating Omicron ‘subvariants’, however these variants have demonstrated ‘neutralization escape’, meaning they have evolved to escape neutralizing antibodies from previous infections or from mRNA injection. Indeed, vaccination appears to be a risk factor for symptomatic disease.

The newer variants seem to differ from previous variants due to the early onset of bacterial pneumonia. While the optimal treatment approach to the symptomatic patient is unclear, it is best to risk-stratify symptomatic patients. Risk factors for hospitalization and death include advanced age (over 60), comorbidities (especially obesity and metabolic syndrome, poor ambulatory status, delayed treatment, high D-dimer), recently vaccinated, and severe symptoms.

High-risk patients should consider:

  • The combination of both HCQ and ivermectin
  • Nattokinase 2000-4000 FU/day for 15 days OR Apixaban 5 mg daily for 15 days OR Rivaroxaban 10 mg daily for 15 days. The escalated use of anticoagulants should only be considered in patients with a low risk of bleeding. Furthermore, the risk of serious bleeding increases as the number of anticoagulant drugs is increased.
  • Spironolactone: 200 mg once daily for 7 days (avoid in patients with impaired renal function)

If symptoms have not markedly improved by day 3 of treatment, one of the following antibiotics should be started. NOTE: providers should prescribe an antibiotic at the first visit.

  • Oral antibiotic:

      • Doxycycline 100 mg twice daily for 5 days (Doxycycline may act synergistically with ivermectin and might be the antibiotic of first choice.); OR
      • Azithromycin (Z-pack) 500 mg day 1, then 250 mg daily for 4 days; OR
      • Amoxicillin/Clavulanate (Augmentin) 500 mg/125 mg tablet twice daily for 7 days.

Hypoxia/shortness of breath: If the patients develop hypoxia or shortness of breath Prednisolone 60 mg daily for 5 days should be prescribed.

About Ivermectin

Ivermectin is a well known, FDA-approved drug that has been used successfully around the world for more than four decades. One of the safest drugs known, it is on the WHO’s list of essential medicines, has been given over 3.7 billion times, and won the Nobel Prize for its global and historic impacts in eradicating endemic parasitic infections in many parts of the world.

To review the totality of supporting evidence for ivermectin in COVID-19, visit our Ivermectin information page.

Ivermectin is a remarkably safe drug with minimal adverse reactions (almost all minor), however its safety in pregnancy has not been definitively established. Talk to your doctor about use in pregnancy, particularly in the first trimester.

Potential drug-drug interactions should be reviewed before prescribing ivermectin.

Ivermectin has been demonstrated to be highly effective against the Omicron variant at a dose of 0.3 to 0.4 mg/kg, when taken early.

Higher doses (0.6 mg/kg) may be required: in regions with more aggressive variants; if treatment starts on or after 5 days of symptoms; in patients in advanced stage of the disease or who have extensive risk factors (i.e., older age, obesity, diabetes, etc.)

Table 1. How to calculate ivermectin dose

Note that ivermectin is available in different strengths (e.g., 3, 6 or 12 mg) and administration forms (tablets, capsules, drops, etc.). Note that tablets can be halved for more accurate dosing, while capsules cannot.

ivermectin dosage by weight

Table 2. Proposed medication schedule for first line treatments

Table 3. A Single-Dose Regimen of Calcifediol to Rapidly Raise Serum 25(OH)D above 50 ng/mL

Ordinary Vitamin D3 Does not work in Acute Illness

According to this webinar (below) by Dr Pierre Kory and Dr. Keith Berkowitz:

Video time from 11:30 - 12:30: 

Vitamin D3 (ordinary form) does not work in acute illness. It doesn't become active for at least a week... Vitamin D3 is for prevention and you should continue to take it if your levels are below 50 ng/ml...

There is only one form of vitamin D that will have an acute impact and that is calcifediol (vitamin D3 analog). 

About FLCCC Alliance

The Front Line COVID-19 Critical Care (FLCCC) Alliance was initially formed as a working group under “emergency” conditions of the early COVID-19 pandemic in response to multiple early reports of COVID patients with an inexplicably high need for prolonged mechanical ventilation and an excessive mortality associated with the prevailing “supportive care only” recommendations disseminated by the majority of national and international health care organizations.

As a group of highly published leaders in critical care with expertise in therapies directed at severe infections, in particular “HAT” therapy first developed by Dr. Paul Marik for the treatment of bacterial sepsis, and along with published high patient survival rates from our centers, we were contacted by equally concerned and motivated colleagues from other specialties.

With the increasing publications in addition to our rapidly accumulating personal clinical experiences and investigations into the pathophysiology of COVID-19 patients, we formulated the MATH+ Hospital Treatment Protocol in March 2020. On August 5, 2020, FLCCC published our findings in the rationale paper Scientific Review of COVID-19 and MATH+.

In October 2020, the FLCCC Alliance identified, based on a review of the recent and rapidly emerging clinical trials evidence, that ivermectin, an anti-parasitic medicine, has highly potent real-world, anti-viral, and anti-inflammatory properties against SARS-CoV-2 and COVID-19. This conclusion is based not only from multiple in-vitro and animal models, but from numerous clinical trials from centers and countries around the world showing repeated, consistent, large magnitude improvements in clinical outcomes when ivermectin is used not only as a prophylactic agent but also in mild, moderate, and even severe disease states. Further, data from large “natural experiments” that appear to have occurred when various regional health ministries and governmental authorities within South American countries initiated “ivermectin distribution” campaigns which then led to temporally associated decreases in case counts and case fatality rates.

Other Potential Treatments

For other potential treatments for COVID-19, check out (constantly updated).

Conclusion and Key Takeaway

If you are an average layperson, you will likely find this protocol overwhelming. This is a guide and may need to be personalized according to your unique situation. Always see or talk to your doctor before taking these drugs, supplements and over the counter products.

Be aware that most of the 'treatment' doses for supplements are above the recommended dietary allowance (RDA) and therefore such doses should not be maintained on a long term basis.

This guide may not be the answer to everything but it could be everything to you or your loved ones.
    • Please do not consider these protocols as personal medical advice, but as a recommendation for use by professional providers. Consult with your doctor, share the information on this website and discuss with her/him.
    • We are fans and affiliates of FLCCC. We do not represent FLCCC. Any opinions are our own.
    • Always see or talk to your doctor before taking these drugs, supplements and over the counter products. Be aware that most of the 'treatment' dosages are above the recommended dietary allowance (RDA) and therefore such dosages should not be maintained on a long term basis. 
    • Our aim here isn't to replace your doctors' advice. It is intended as a sharing of knowledge and information. Do take note that supplements are not 100% protective or curative against COVID-19.
    • The I-MASK+ protocol is a bridge to vaccines and a safety net for those who cannot or have not been vaccinated; or are vaccinated and have concerns regarding declining protection against emerging variants. Vaccines have shown efficacy in preventing the most severe outcomes of COVID-19 and are an important part of a multi-modal strategy that must also include early treatment. The decision to get a vaccine should be made in consultation with your health care provider. 
    • You still need to follow the advice given by CDC, WHO and your local authority in terms of local guidelines such as mask wearing, social distancing, vaccination and avoiding crowds. It's better to combine multiple strategies in order to defend yourself against this virus.
    • According to US NIH: "...Guidelines should not be considered mandates. The choice of what to do or not to do for an individual patient is ultimately decided by the patient and their provider."

    Z-Stack Supplement

    In an effort to make it easier for patients, Dr Zelenko has developed an oral supplement that contains all four key ingredients (which was based on his Nobel Prize-nominated Zelenko Protocol): Quercetin, vitamin D3, C and zinc. It’s referred to as 'Z-Stack Supplement.

    Z-Stack Vitamin cocktail provides key ingredients needed in order to help your body fight off this deadly invader. Studies have shown that treatment needs to be started 'early'. Don't wait until it's too late to start treatment – keep a bottle on hand for peace of mind. 

    The Z-Stack Vitamins are Kosher certified, GMP certified and made in the USA.

    The cost of the Z-STACK vitamin cocktail is $55 per bottle for a one month supply.

    Where to buy Z-Stack: Here is the link: Z Stack Supplement.

    Note: To get 10% OFF, please use this coupon code: ONEDAYMD


    1. I think Table 2 overstates the amounts of Vitamin D by a factor of 10. It mentions "50,000 IU" vitaimin D caps, when I think the highest available is 5,000 IU. I think 50,000 IU might be toxic.

    2. I was told ivermectin would cause confusion. Is there anything to that?


    Post a Comment

    Popular posts from this blog

    Dr Peter McCullough: How to Detox Spike Protein from Body

    Dr Peter McCullough: Povidone Iodine, Oral and Nasal Hygiene (2024)

    Dr Peter McCullough Early Treatment Protocol

    Find a Doctor to prescribe Hydroxychloroquine, Ivermectin and Early Outpatient Treatments (2024)

    FLCCC I-Recover Protocol: Post Vaccine Treatment Protocol (2024)

    How to Make Povidone Iodine 1% Nasal Spray (2024)

    Quercetin and Zinc: Zelenko Treatment Protocol

    America's Frontline Doctors Early Treatment Protocol and Contact a Physician 2023

    FLCCC I-CARE COVID Treatment Protocol for Outpatients (2024)


    Show more


    Show more