User Guide
Mega Vitamin A

In this guide, vitamin A refers specifically to retinyl palmitate — the type of vitamin A in Dr. Green Mom’s Mega Vitamin A supplement.

We will discuss daily dosing as well as high dose, also known as a megadose, of vitamin A, which can promote a strong anti-viral immune response. [1-12] While megadosing can be an effective treatment strategy, the body stores vitamin A, which means that high doses, over time, can become toxic. [6]

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Mega Vitamin A

Please note that megadosing is not designed to be combined with regular supplementation beyond food sources. Either have your child supplement daily with a lower dose of vitamin A (cod liver oil or beef liver capsules, for example) or give them a megadose.

This guide is designed to help facilitate a conversation with your healthcare provider, particularly if you are going to megadose. Informed discussions with your healthcare provider will help you determine the dosing schedule that makes the most sense for your child.

Vitamin A Daily Dosing Strategies

When giving a daily dose to yourself or your child, consider the Recommended Daily Allowance (RDA) values. The RDA is determined to prevent deficiency in 97% of the population.

The FDA requires vitamin A amounts to be listed in mcg RAE, a standard unit that reflects how much vitamin A the body can absorb and use.

RDA for Vitamin A

Age	Male	Female	Pregnancy	Lactation
Birth to 6 months*	400 mcg RAE	400 mcg RAE
7-12 months*	500 mcg RAE	500 mcg RAE
1-3 years	300 mcg RAE	300 mcg RAE
4-8 years	400 mcg RAE	400 mcg RAE
9-13 years	600 mcg RAE	600 mcg RAE
14-18 years	900 mcg RAE	700 mcg RAE	750 mcg RAE	1200 mcg RAE
19-50 years	900 mcg RAE	700 mcg RAE	770 mcg RAE	1300 mcg RAE
51+	900 mcg RAE	700 mcg RAE

*AI, equivalent to the mean intake of vitamin A in healthy breastfed infants.

Products with Vitamin A

Product	Child/Adult Use	Amount of Vitamin A
Mega Vitamin A	Both	1500 mcg RAE (~5000 IU) per drop
Oh My Cod! Liver Oil	Both	540 mcg RAE (~1800 IU) per serving
Essential Immune Support™✝︎ Infants & Kids	Children	300 mcg RAE (~1000 IU) per scoop
Grass Fed & Finished Beef Liver Capsules	Both	4 capsules of Grass Fed & Finished Beef Liver = ⅓ oz of fresh liver. According to the USDA data table, ⅓ oz of beef liver contains approximately 450-550 mcg RAE of vitamin A. Beef liver is a natural, unrefined product that will have fluctuations in vitamin A content.

Vitamin A Megadosing Protocols

In this guide, we will outline three vitamin A megadosing protocols. There is no one right way to megadose, and all of these strategies yield
positive results. Your healthcare provider can best advise you.

Conventional Recommendations

Age	Dose	Frequency
0-6 months	50,000 IU (15,000 mcg RAE)	One dose, two days in a row, every 4-6 months
6–12 months	100,000 IU (30,000 mcg RAE)	One dose, two days in a row, every 4-6 months
12 months +	200,000 IU (60,000 mcg RAE)	One dose, two days in a row, every 4-6 months

The dosing model most recommended for pediatric viral infections. Based on geographic regions with higher rates of Vitamin A deficiency. [13]

Dr. Green Mom’s Recommendations

Age	Dose	Frequency
0-6 months	25,000 IU (7500 mcg RAE)	1 or 2 days in a row, every 3 months
6–12 months	50,000 IU (15,000 mcg RAE)	1 or 2 days in a row, every 3 months
12 months +	100,000 IU (30,000 mcg RAE)	1 or 2 days in a row, every 3 months

The conventional recommendations are based on populations in geographic regions with a high risk of nutritional deficiencies. As nutritional deficiencies are less common in U.S. children, Dr. Green Mom recommends ½ dosing of the conventional recommendations.

The Japan Study’s Recommedations

Age	Dose	Frequency
0-6 months	100,000 IU (30,000 mcg RAE)	1 day, every 3 months
6–12 months	100,000 IU (30,000 mcg RAE)	1 day, every 3 months
12 months +	100,000 IU (30,000 mcg RAE)	1 day, every 3 months

The Japanese have very few nutritional deficiencies, so their vitamin A research can be applied to the North American population. [5]

How to Megadose with Mega Vitamin A

One drop of Mega Vitamin A has 1500 mcg RAE (~4995 IU) of vitamin A palmitate (retinyl palmitate).

Dose	Number of Drops
25,000 IU (7500 mcg RAE)	5 Drops
50,000 IU (15,000 mcg RAE)	10 Drops
100,000 IU (30,000 mcg RAE)	20 Drops
200,000 IU (60,000 mcg RAE)	40 Drops

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Free From Allergens

Mega Vitamin A contains NO artificial flavors, colors, or preservatives.

Gluten & Wheat Free

Dairy Free

Egg Free

Fish Free

Shellfish Free

Nut Free

Soy Free

No Artificial Flavors

No Artificial Colors

No Preservatives

What if my child is already taking a supplement with Vitamin A and I want to megadose?

Given the near-toxic acute dosing levels, if you follow the WHO or Japan Study megadose guidelines (see charts), discontinue daily vitamin A supplementation for two to three months, unless otherwise directed by your physician.

The Dr. Green Mom megadose guidelines are lower than the other two strategies’, making it safer to resume daily dosing right away while still maintaining a protective level of vitamin A.

Keep in mind that most children taking a daily dose of vitamin A will already have adequate stores and will not need to megadose unless recommended by a physician.

Always consult your child’s physician.

Vitamin A to Optimize Vaccination

Vitamin A can help your child mount an effective immune response at the time of vaccination. It plays a key role in strengthening the mucosal barriers of the gut, mouth, nose, and respiratory tract. Vitamin A supports the growth and differentiation of immune cells — factors essential for optimizing vaccine effectiveness. [14, 15]
If you’re choosing to vaccinate, make it count.

Types of Vaccines: Live vs. Non-Live

There are two main categories of vaccines: live attenuated and non-live (inactivated or subunit) vaccines.

Live Virus Vaccines

Live attenuated vaccines use weakened viruses that replicate just enough to trigger an immune response and antibody production—without causing disease. In the routine schedule, live vaccines include:

MMR (measles, mumps, rubella)
Varicella (chickenpox)
Rotavirus

When giving a live vaccine, select one of the age-appropriate vitamin A dosing strategies listed above. Administer a single megadose either the day before or the morning of the vaccination. Any of the recommended strategies will support the desired immune response.

Space megadoses 2-3 months apart. Follow this guideline if you have vaccines booked close together and avoid megadosing repeatedly in a short span of time.

Non-Live Vaccines

For all other vaccines (non-live), give four drops 6000 mcg RAE (20,000 IU) of liquid vitamin A the day before vaccination to support immune readiness.

This dose of vitamin A does not need to be spaced months apart, if you have a few non-live vaccines booked in a row you can use this dosing for each one. It is only the megadose that needs to be spaced 2-3 months apart.

Vitamin A Toxicity

Vitamin A is a fat-soluble vitamin, meaning the body can store any excess. These stored reserves are beneficial, but if intake is too high, vitamin A can build up and cause toxicity.

Toxicity is a common concern for parents. It’s important to clarify that we are not talking about beta carotene—the plant-based precursor to vitamin A. The body only converts beta carotene into active vitamin A (retinol) when it needs it, so there is no risk of toxicity from beta carotene.

Retinyl palmitate, the form of vitamin A used in our supplement, is preformed vitamin A, which the body can store directly. In this case, toxicity is possible if doses are too high.

Toxic dosing thresholds

Acute toxicity (a very large single serving): 7500 mcg RAE or 25,000 IU per kg body weight or more.

Example: A 50 lb. child weighs about 23 kg. At this weight, acute toxicity would require around 172,000 mcg RAE (~573,000 IU) taken at once. To avoid toxicity, vitamin A intake should always stay well below this level.

Chronic toxicity (high intake over weeks to months): 1200 mcg RAE or 4000 IU per kg body weight daily for 6 15 months.

Example: For a 50 lb. child (23 kg), this equals about 27,600 mcg RAE (~92,000 IU) per day for several months. Staying under this amount prevents chronic toxicity. [16]

Symptoms of Vitamin A Toxicity

Acute (large one-time dose, often accidental ingestion):

Nausea, vomiting, drowsiness, irritability
Bulging fontanelle in infants
Headache

Chronic (excess over weeks/months):

Slowed growth, bone pain, increased fracture risk
Liver enlargement or damage
Dry, itchy skin; cracked lips; hair loss
Irritability, fatigue, poor weight gain

Vitamin A in Pregnancy

In North America, where vitamin A deficiency is rare, do not supplement beyond your prenatal vitamin without express consent from your physician. Excess vitamin A has been linked to teratogenicity (congenital disabilities).

If you’ve been taking vitamin A supplements and discover you are pregnant, it’s best to stop right away. Research shows that doses above 3000 mcg RAE (10,000 IU) daily are linked with an increased risk of congenital disabilities—about 1 in 57 babies. [17] The good news is that most over-the-counter vitamin A supplements contain much lower amounts, so the likelihood of harm is negligible. The most important step is to discontinue use as soon as you know you’re pregnant.

Questions to Ask Your Healthcare Provider About Dosing Vitamin A

FAQs

Do infants who are breastfed or formula-fed require additional vitamin A?

Breast milk can have the perfect amount of vitamin A for your baby, but if the mother is deficient, the baby will not get enough. [18, 19]

What are the potential benefits and risks of high-dose vitamin A supplementation for infants?

Vitamin A can help your child mount a more effective immune response at the time of vaccination. It plays a key role in strengthening the mucosal barriers of the gut, mouth, nose, and respiratory tract. Vitamin A supports the growth and differentiation of immune cells — factors essential for optimizing vaccine effectiveness. Vitamin A also supports healthy vision and lowers infant and childhood mortality. [14, 15]

Since Vitamin A is a fat-soluble vitamin which is stored in the body, high-dose Vitamin A may cause toxicity. A large, acute, or one-time dose may cause nausea, vomiting, drowsiness, irritability, bulging fontanelles in infants, and headaches. A chronic toxicity, Vitamin A taken in excess over weeks/months may cause slowed growth, bone pain, increased fracture risk, liver enlargement or damage, dry itchy skin, cracked lips, hair loss, irritability, fatigue, and poor weight gain. [6,15]

Can my infant safely receive both dietary and supplemental vitamin A?

Yes, your infant can safely receive both dietary and supplemental vitamin A but only when the total intake stays within safe limits. Follow the RDA guidelines and consult your healthcare provider to ensure your infant receives the appropriate amount.

What should I do if my infant spits up after a dose of vitamin A?

Speak to your doctor if your infant spits up a megadose of Vitamin A. You will want to assess how much was retained.

If most of the dose was spit out, they may suggest you repeat the megadose.
If only a small amount was spit up, or it happened after some time, enough may have been absorbed and re-dosing would not be necessary.

Are there any risks if my infant receives an extra megadose of vitamin A?

If an infant receives an extra (duplicate) megadose of Vitamin A, especially within a short time frame, you should contact your healthcare provider or local poison control center immediately to determine if monitoring or treatment is needed. Since Vitamin A is fat-soluble and stored in the body, an excess amount can lead to toxicity.

What megadose protocol should I follow if supplementing vitamin A?

Work with your healthcare provider and choose the Vitamin A megadosing protocol that works best for you and your family. Choose from one of the three options below:

Conventional Recommendations
Dr. Green Mom’s Recommendations
The Japan Study Recommendations

If I start with a high-dose vitamin A regimen and have concerns, can I stop or adjust the dosage?

Yes, if you start a high-dose vitamin A regimen and have concerns, you should absolutely discuss them with your healthcare provider, and you can stop at any time.

If the dose was already given, it can’t be undone, but future doses can be reassessed or postponed based on your child’s health, nutritional status, and risk factors.

What happens if I miss a vitamin A dose on a two-day schedule?

If you miss a vitamin A dose on a two-day schedule, simply dose the next day.

Summary

Both megadosing and daily dosing of vitamin A are safe and effective strategies to help your family manage viral infections or optimize vaccination. [1-12, 14, 15] Vitamin A can be stored in the body, and therefore, one must be mindful of its toxicity. [6, 15] This is why we adopt a structured dosing plan, whether your child is megadosing or daily dosing, also taking into account vitamin A from all sources – foods like liver to supplements like our Mega Vitamin A.

Megadosing is done 1-2 times, spaced at least 3 months apart. Using the charts above and your healthcare provider’s guidance, you can select a dosing strategy that works for your child without concern for their well-being.

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References:

Rohani, M., Mozaffar, H., Mesri, M., Shokri, M., Delaney, D., & Karimy, M. (2022). Evaluation and comparison of vitamin A supplementation with standard therapies in the treatment of patients with COVID-19. Eastern Mediterranean health journal. 28(9), 673–681. https://doi.org/10.26719/emhj.22.064
Soares, M. M., Silva, M. A., Garcia, P. P. C., Silva, L. S. D., Costa, G. D. D., Araújo, R. M. A., & Cotta, R. M. M. (2019). Effect of vitamin A supplementation: a systematic review. Ciencia & saude coletiva, 24(3), 827–838. https://doi.org/10.1590/1413-81232018243.07112017
Tepasse, P. R., Vollenberg, R., Fobker, M., Kabar, I., Schmidt, H., Meier, J. A., Nowacki, T., & Hüsing-Kabar, A. (2021). Vitamin A Plasma Levels in COVID-19 Patients: A Prospective Multicenter Study and Hypothesis. Nutrients, 13(7), 2173. https://doi.org/10.3390/nu13072173
Li, R., Zhao, W., Wang, H., Toshiyoshi, M., Zhao, Y., & Bu, H. (2022). Vitamin A in children’s pneumonia for a COVID-19 perspective: A systematic review and meta-analysis of 15 trials. Medicine, 101(42) e31289. https://doi.org/10.1097/MD.0000000000031289
Kawasaki, Y., Hosoya, M., Katayose, M., & Suzuki, H. (1999). Kansenshogaku zasshi. The Journal of the Japanese Association for Infectious Diseases, 73(2), 104–109. https://doi.org/10.11150/kansenshogakuzasshi1970.73.104
Olson, J. M., Ameer, M. A., & Goyal, A. (2023). Vitamin A toxicity. In StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK532916/
Sarohan, A. R., Akelma, H., Araç, E., Aslan, Ö., & Cen, O. (2022). Retinol Depletion in COVID-19. Clinical nutrition open science, 43, 85–94. https://doi.org/10.1016/j.nutos.2022.05.007
Penkert, R. R., Smith, A. P., Hrincius, E. R., McCullers, J. A., Vogel, P., Smith, A. M., & Hurwitz, J. L. (2021). Effect of Vitamin A Deficiency in Dysregulating Immune Responses to Influenza Virus and Increasing Mortality Rates After Bacterial Coinfections. The Journal of infectious diseases, 223(10), 1806–1816. https://doi.org/10.1093/infdis/jiaa597
Turrubiates-Hernández, F. J., Hernández-Bello, J., Oregón-Romero, E., González-Estevez, G., & Muñoz-Valle, J. F. (2021). Participación de la vitamina A en la producción de IgA secretora en el epitelio del tracto respiratorio para la potencial protección de infección por SARS-CoV-2 [The involvement of vitamin A in the production of secretory IgA in the respiratory epithelium for potential protection against SARS-CoV-2 infection]. Revista alergia Mexico (Tecamachalco, Puebla, Mexico : 1993), 68(3), 185–197. https://doi.org/10.29262/ram.v68i3.977
Midha, I. K., Kumar, N., Kumar, A., & Madan, T. (2021). Megadoses of retinol: A possible immunomodulation in Covid-19 illness in resource-limited settings. Reviews in medical virology, 31(5), 1–14. https://doi.org/10.1002/rmv.2204
Le, H., & Ko, G. (2016). Anti-viral effect of vitamin A on norovirus infection via modulation of the gut microbiome. Scientific reports, 6, 25835. https://doi.org/10.1038/srep25835
Huang, Z., Liu, Y., Qi, G., Brand, D., & Zheng, S.G. (2018). Role of Vitamin A in the Immune System. J Clin Med. Sep 6;7(9):258. doi: 10.3390/jcm7090258. PMID: 30200565; PMCID: PMC6162863.
World Health Organization. (2011). Vitamin A supplementation in infants and children 6–59 months of age. WHO Guidelines. https://apps.who.int/iris/handle/10665/44664
Surman, S. L., Penkert, R. R., Jones, B. G., Sealy, R. E., & Hurwitz, J. L. (2016). Vitamin Supplementation at the Time of Immunization with a Cold-Adapted Influenza Virus Vaccine Corrects Poor Mucosal Antibody Responses in Mice Deficient for Vitamins A and D. Clin Vaccine Immunol. Jan 6;23(3):219-27. doi: 10.1128/CVI.00739-15. https://www.ncbi.nlm.nih.gov/pubmed/26740391
Jensen, K. J., Fisker, A. B., Andersen, A., Sartono, E., Yazdanbakhsh, M., Aaby, P., Erikstrup, C., & Benn, C. S. (2016). The effects of vitamin A supplementation with measles vaccine on leucocyte counts and in vitro cytokine production. Br J Nutr. Feb 28;115(4):619-28. doi: 10.1017/S0007114515004869. Epub 2015 Dec 18.
World Health Organization. (2016). Adverse events following administration of vitamin A supplements with immunization. Geneva: WHO. https://cdn.who.int/media/docs/default-source/immunization/intervention/adverse_events_vita.pdf?sfvrsn=9f783ae6_3
Rothman, K. J., Moore, L. L., Singer, M. R., Nguyen, U.-S. D. T., Mannino, S. M., & Milunsky, A. (1995). Teratogenicity of high vitamin A intake. The New England Journal of Medicine, 333(21), 1369–1373. doi:10.1056/NEJM199511233332101.
Bezerra, D. S., Araújo, K. F., Azevêdo, G. M., & Dimenstein, R. (2009). Maternal supplementation with retinyl palmitate during immediate postpartum period: potential consumption by infants. Revista de saude publica, 43(4), 572 579. https://doi.org/10.1590/s0034-89102009005000039
Grilo, E. C., Medeiros, W. F., Silva, A. G., Gurgel, C. S., Ramalho, H. M., & Dimenstein, R. (2016). Maternal supplementation with a megadose of vitamin A reduces colostrum level of α-tocopherol: a randomised controlled trial. Journal of human nutrition and dietetics : the official journal of the British Dietetic Association, 29(5), 652–661. https://doi.org/10.1111/jhn.12381

This content is for educational purposes only and not a substitute for medical advice. Always consult your healthcare provider before beginning any supplement program.

✝︎ These statements have not been evaluated by the Food and Drug Administration (FDA). This product is not intended to diagnose, treat, cure, or prevent any disease.

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