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The Overdose Risks of Vitamins: Why Proper Dosage Matters

by SmartyPants Staff

Some individuals subscribe to the thought that, “if a little is a good thing, a lot is better.”  

That may be true in some activities and some circumstances when it comes to your health, but with optimal vitamin intake and supplementation that’s simply not true.

According to Medscape, the majority of Americans consider vitamins safe, and that belief alone can increase the likelihood of taking too many, as there is no perceived risk in the minds of many people.  

The truth is, too much of certain vitamins can lead to a vitamin overdose, which can be dangerous and, in some cases, life threatening.

That is certainly not true with many vitamins – you’re safe with a multivitamin that covers about 100% of the Daily Value (DV) for all vitamins and minerals. Daily Values are the levels of vitamins and minerals set by the Food and Drug Administration for the general population.

But there are some nutrients to be careful with…

Common vitamins and vitamin overdose symptoms

Vitamin D

Recently, there’s been a lot of buzz about vitamin D deficiency and the problems vitamin D deficiency can cause in individuals, and for good reason. 

Vitamin D, known as “the sunshine vitamin,” is primarily responsible for the regulation of calcium and phosphorus in the bones.*  Without vitamin D, you’d be a softy – quite literally!  

Coupled with a lack of calcium intake and physical activity, your bones would likely become soft and weak over time, increasing the risk of osteoporosis, discomfort in the bones, and even a greater risk of broken bones!

But, pay attention – while vitamin D overdose is extremely rare, there is such a thing as too much.  Too much vitamin D can lead to a vitamin overdose and can cause permanent damage to your kidneys and heart.

Vitamin D overdose symptoms can lead to bothersome health issues, although perhaps temporary, include nausea, vomiting, alternating constipation and diarrhea.  Sometimes vitamin D overdose can even result in dangerous heart rhythm abnormalities.

In addition, a vitamin D overdose in pregnancy has been shown to increase the potential of mental retardation in babies.  Though the recommended daily requirement of vitamin D is around 1,000 IU, many doctors believe this is too low and regularly prescribe more to those who are vitamin D deficient.  

So how much is too much vitamin D?

It has been shown that taking 40,000 IU of vitamin D in infants and 50,000 IU in adults for several months can cause toxicity.  Make no mistake, that is a lot of vitamin D!  

The best way to determine the appropriate amount of vitamin D for you and avoid overdose is to avoid so-called mega-dosing, consult your own healthcare professional, and have your levels tested.

If you are pregnant, make sure that you follow your healthcare professional’s guidelines for safe vitamin D supplementation to avoid a vitamin D overdose.

Vitamin B

We hear a lot about B vitamins, a group of 8 distinct vitamins, each responsible for aiding various functions in the body.  The functions of the vitamin B group range from supporting the rate of metabolism, promotion of healthy skin and hair, as well as memory support.* 

Since the vitamin B group is responsible for all of that good stuff, can you really get too much resulting in a vitamin B overdose?  

With some of the B vitamins, unfortunately, yes.  In fact, a vitamin B6 overdose can lead to nerve toxicity, while B3 can lead to nausea, jaundice, and liver toxicity.  Too much folic acid, too, can mask the symptoms of a B12 deficiency.

So how much is too much vitamin B?  

Typically, 300 mg of B6 is scary territory, while 2000 mg of B3 is risky.  For folate, the Institute of Medicine recommends adult men and women not consume more than 1000 mg per day. In order to avoid a vitamin B overdose, make sure you consult your healthcare professional.

Vitamin A

Vitamin A supplementation may enable you to delay getting reading glasses since it supports the function of the human eye, but a severe vitamin A overdose can actually cause death.* 

Normally, a vitamin A overdose progresses slowly as it accumulates in the body, particularly since it is a fat-soluble vitamin and is stored in your fat cells.  The initial signs of a vitamin A overdose may emerge as rather benign health issues: dry, rough skin, cracked lips, and hair loss. 

Latter symptoms of vitamin A overdose may include irritability, headache, high level of liver enzyme in blood, and liver disease.  In addition to a slow progressing vitamin A overdose, there is such a thing as an acute vitamin A overdose. 

This is a far more serious type of vitamin overdose with symptoms ranging from vomiting, high pressure in the brain, and even death.

How much is too much vitamin A?

The vitamin A recommended daily dose for children 4 to 8 years old is 3000 IU and for adults is 10,000 IU.  Staying within these limits is advised, but it is best to check with your healthcare professional to determine what is best for you.

If you're taking a supplement, it's also important to consider which form of vitamin is in your multivitamins.

Beta carotene is the most important provitamin A (found mostly in vegetables) and is converted to vitamin A as needed in the body. As a result, it’s not associated with the same toxicity risks as preformed vitamin A.

For this reason, we use a 50/50 beta-carotene/retinyl palmitate blend because it helps moderate your intake of vitamin A. With our premium 50/50 mix, your body will only convert beta carotene to vitamin A as needed, based on your individual levels of this essential vitamin.

We include this beta-carotene/retinyl palmitate blend in our SmartyPants Organic formulas and SmartyPants core line formulas.


Probably one the most widely known and one of the most dangerous vitamin overdoses, particularly for children, is an iron overdose.  While iron is necessary for red blood cells and the prevention of anemia, an iron overdose can lead to death, and is actually the leading cause of fatal poisoning in children younger than 5.  

This is the major reason why we don’t put iron in our gummies.  However, you can find iron in our multivitamin capsule Men's, Women's and Prenatal Formulas.

The best source of iron is from foods like spinach, sweet potatoes, whole wheat bread, strawberries, and eggs.  

If your healthcare professional tells you that you or your child still need more iron, using liquid iron with a dropper will allow you to control the iron levels and has no appeal to kids as a treat.  

How much is too much iron?

The recommended daily requirement of iron for adults varies depending on age.  The same goes for the recommended daily requirement for children.

What to do if you suspect a vitamin overdose

Depending on the severity of the health issues, a vitamin overdose may not be cause for immediate alarm.  If the health issues aren’t life threatening or life altering, simply reduce or discontinue the use of a daily multivitamin.  

However, if you have any concerns for you or your family member, contact a healthcare professional sooner than later.  Most vitamin overdose problems occur in children under six years of age.  

If acute life threatening symptoms appear, seek medical assistance immediately

Storage of supplements is also important for every household. It helps to select a product with a Child Resistant Cap for extra safety.

Vitamin supplementation could be an important part of a healthy lifestyle, provided there are no underlying health issues.  The risk of overdose in many of the vitamins listed are low – in fact, deficiency and insufficiency is the struggle with each most of us face.  

Even so, overdose is a potential for those of us who, when attempting to correct our insufficiency, go overboard.

As always, before implementing any vitamin regimen, seek the advice of a healthcare professional to insure the safety of your health!

So how can you be sure SmartyPants supplements are safe?

We create each and every product with our own children in mind. The safety of our products is a top priority at SmartyPants.

From start to finish, our internal Quality Assurance team is working hard to make sure that all our products meet and (hopefully) exceed the rigorous standards that we promise our customers.

Furthermore, SmartyPants is unique in the industry for focusing on the nutrients that are the toughest to obtain from our diets alone to help fill those dietary gaps.

We always recommend you get nutrients from food first, so we formulate our products to complement the average American diet, not replace it.

That means that we include safe amounts of vitamins and minerals in our products. After all, we believe it’s important to focus on how all of the available scientific research provides a story to shape the recommendations for how much of each nutrient we should eat daily.

Our supplements only use FDA GRAS (generally recognized as safe) ingredients, and every batch of finished product third-party lab tested for quality assurance. 

So you can always trust that what's on the label is what's inside the bottle

We care about each and every ingredient that goes into SmartyPants.
You can learn more about our testing and ingredient selection process here.

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