Can You Overdose On Vitamins?: A Guide To Supplements And Safety

June 07, 2018

Can You Overdose On Vitamins?: A Guide To Supplements And Safety

Getting the proper nutrition is essential for your health. You only need small amounts of certain vitamins, and they should mostly come from your food. However, millions of Americans take a vitamin every day to catch up on some of the essential vitamins and minerals that they miss out on in their diet.

But can you overdose on vitamins?

The answer is: yes, absolutely. While it's almost impossible to eat too much of any vitamin naturally through the food you eat, you can overdose on some vitamins if you take too many vitamins or supplements for long periods of times.

Read on to learn more about the dangers of vitamin overdose and how to supplement safely.

Aren't Supplements Safe?

For the most part, the vitamin supplements you see in the store are sold in dosages that won't hurt you as long as you follow the directions on the label. However, sometimes people take "mega-doses" of vitamins, hoping the supplements will treat or prevent specific health problems.

There are a number of problems associated with taking mega-doses of vitamins. First, there's very rarely actual scientific research around taking massive amounts of any vitamin. The only research that says that this might help is the kind that needs close guidance from a medical doctor. So, you're probably wasting your money.

Second, you can develop health problems if you mega-dose with some vitamins. These problems are usually reversible if you stop taking mega-doses, but this isn't always the case.

If you think you have been taking a vitamin in large doses, contact your doctor as soon as possible.

Which Vitamins Are Dangerous in Large Doses?

The Food and Nutrition Board of the Health and Medicine Division of the National Academies of Science, Engineering, and Medicine has established the Tolerable Upper Intake Levels for all vitamins and minerals, also known as the "UL."

The UL is the highest level of a nutrient that you can take without posing a health risk to yourself if you are a healthy person.

Here are the ULs for some of the most common vitamins as well as what can happen if you take too much.

Vitamin A

Vitamin A is important for maintaining normal vision, cell development, and a functioning immune system. Adults need between 700 and 900 micrograms per day. You can find this vitamin naturally in liver, fish, meat, dairy products, and colorful fruits and vegetables.

Vitamin A is a fat-soluble vitamin, which means that your body can store it and accumulate it over time. If you take a lot of vitamin A over a long period of time, you can experience intracranial pressure, dizziness, nausea, liver damage, headaches, rash, bone and joint pain, a coma, and even death.

Vitamin C

This vitamin is essential for strong connective tissue and the functioning of your immune system function. It's an antioxidant that can prevent damage from free radicals, as well. The average adult needs between 75 to 90 milligrams per day, and it's found in fruits and veggies.

Many people take vitamin C supplements in the hopes that it will help ward off colds and flu symptoms. However, traditionally, adults can only tolerate about 2,000 mcg of vitamin C a day.

If you take a lot of vitamin C, it's not going to be life-threatening. However, it can cause unpleasant symptoms like diarrhea, nausea, and abdominal cramps. It is also linked to kidney stones.

Vitamin D

Vitamin D can help your body absorb and use calcium, so if you don't get enough you can have a high risk of weakened bones and osteoporosis. Most adults need at least 600 IU, or International Units, every day.

Vitamin D is a vitamin that is difficult to get enough of from food. However, your body makes it when your skin is exposed to sunlight. Regardless, vitamin D is a popular supplement.

As an adult, you can only take about 15 mg of Vitamin D a day.

If you take too much vitamin D in supplements you can raise the level of calcium in your blood. This is bad for your heart and kidneys. It's worth noting that you cant get too much vitamin D from the sun and it's very hard to get too much of it from your diet.


Niacin is a vitamin that helps convert the food that you eat into energy. A niacin deficiency is rare because it's found in a lot of foods. However, it's sold as a supplement to manage cholesterol levels.

The UL for niacin in an adult is 35 mg. And if you take too much, you can have liver damage and hurt your blood sugar levels if you have diabetes.

Also, if you take too much niacin in the short term, you can experience something called "niacin flush" which isn't harmful but is uncomfortable and scary.

Vitamin B6

Vitamin B6 allows your body to turn protein and sugar into energy. It also helps produce hemoglobin and aids in nervous system function. The average adult needs about 1.3 mg a day, and it's pretty hard to actually have a deficiency.

However, B6 supplements are used to reduce homocysteine levels and can treat both depression and carpal tunnel syndrome. The upper limit for vitamin B6 in an adult is 100 mg.

If this limit is breached, you can cause damage to your nerves and skin, develop nausea, and have a sensitivity to light.

Folic Acid

Flate is a B-complex vitamin that our bodies need to make DNA, divide our cells, and grow. It's found in fruits and green veggies. Folic acid is a synthetic form of folate that is often found in bread and cereal.

Most adults need about 400 mcg a day, while the UL is 1,000 mcg. And if you overdose on folic acid, you can develop nerve damage and increase the risk of colorectal cancer.

Can You Overdose On Vitamins?

So, can you overdose on vitamins? We hope that you understand that it is very possible to experience a vitamin overdose. If you want to continue to safely take supplements, you have to take them according to the instructions on the package label. Any additional supplementation needs to be done under doctor supervision.

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