6 Vitamins You Can Overdose On

Taking too many of these vitamins and minerals can be dangerous, even deadly

Lauren David,

Updated June 29, 2026

AARP

Reviewed by

Zachary Cox, PharmD

Comments

En español

Updated June 29, 2026

illustration of a pill capsule half is blurry

The Voorhes/Gallery Stock

Key takeaways

Fat-soluble vitamins build up in the body, making excess intake riskier than many expect.
Many older adults meet their vitamin needs through food and may not need additional supplements.
High-dose supplements can trigger serious problems, from nerve damage to kidney failure.

Vitamin use is popular among older Americans. Nearly 80 percent of adults 50 and older take vitamins or supplements, according to a 2021 survey by AARP. For adults 65 and older, that number rises to 83 percent.

Although vitamins can be helpful for people with deficiencies, older Americans should be cautious about how much they take and mindful of potential interactions with medications.

Overuse can lead to serious health problems — and in rare cases be fatal.

Beware of supplement claims

Supplements are heavily marketed, sometimes with unsubstantiated claims. For example, a company might say its supplement will prevent heart disease, even though there isn’t evidence to back that up, says Lauren Haggerty, a former clinical pharmacist at Johns Hopkins Medicine who now works for AstraZeneca.

Also, keep in mind that the Food and Drug Administration (FDA) doesn’t regulate the supplement market the same way it does medications.

“While there’s some regulation on how they’re produced, the FDA isn’t really reviewing them to make sure that they’re safe or effective before they go to market,” Haggerty says.

The two types of vitamins

There are two types of vitamins: water-soluble and fat-soluble. Water-soluble vitamins don’t build up in the body; the excess is usually flushed out in urine unless taken in very high doses, Haggerty says.

Fat-soluble vitamins — like vitamins A, D, E and K — are stored in the body and best absorbed with meals that contain healthy fats.

“We definitely want people to be cautious with [fat-soluble vitamins] because they will just build up in the system, and those are the ones that can cause more toxicity in excess,” says Dr. Wendolyn Gozansky, a senior clinician investigator at the Kaiser Permanente Colorado Institute for Health Research.

Speak to your doctor first

Many people take supplements before consulting with their doctor.

“A lot of patients will consume vitamins because they were sold to them by some marketing strategy or someone’s recommendation,” says Dr. Matthew Farrell, a family medicine physician at the Ohio State University Wexner Medical Center. Because of this, many people take supplements they don’t need.

“I make it a point to be sure that I’m asking people everything that they’re taking for their health and understand what that is so that I can be sure that I know that they’re getting the right amount of what they need,” Gozansky says.

Most people get enough essential vitamins and minerals through their diet and don’t need supplements — and experts say that’s best.

“For most people, if they’re eating a pretty balanced diet with fruits and vegetables, whole grains, low-fat proteins, dairy and beans, then I would say [they] most likely [don’t need a supplement], unless it’s recommended by a doctor because they’re specifically deficient in something,” Haggerty says.

It’s a lot easier for the body to absorb nutrients through food rather than a pill, and there’s less concern of overdosing. “It’s pretty rare for someone to take too much of a vitamin through their diet,” Haggerty says.

6 vitamins and minerals you can overdose on

Here are six common vitamins and minerals that people can overconsume. Be aware that upper safety limits for these vitamins include combined amounts from vitamins and food.

1. Vitamin A

Vitamin A is important for vision, the immune system, cell division and more. According to the National Institutes of Health (NIH), women should consume 700 micrograms of retinol activity equivalents (RAE) per day, and men should have 900 micrograms (mcg) RAE.

Excess vitamin A is absorbed by the body and can build up in the liver, causing chronic toxicity. Acute toxicity, called hypervitaminosis A, occurs when a person repeatedly takes a higher dose, more than 1,200 mcg/kg (kilograms) daily (or more than 84,000 mcg [84mg] daily for an average weight adult), over months, which is more than 100 times the recommended dietary allowance (RDA), according to NIH.

“You can have some acute symptoms like nausea, vomiting, vertigo, blurry vision” from too much vitamin A, Farrell says. Other symptoms include severe headaches, aching muscles and coordination problems. In severe cases, too much vitamin A can cause an increase in cerebrospinal fluid pressure, leading to drowsiness and, eventually, coma and even death.

If you have a preexisting liver condition, excess vitamin A is concerning. “It can hurt your liver if you already have liver problems,” Haggerty says.

Vitamin A RDA 

700 mcg per day for women
900 mcg per day for men

2. Vitamin B6

Vitamin B6 is important for maintaining overall health and supporting many metabolic processes. It also supports brain development and mood.

Consuming too much B6 from food is difficult. However, it is possible to get too much if you’re taking supplements. Taking high doses of B6 — more than 250 milligrams (mg) per day — can cause nerve damage and nerve pain, Haggerty says.

Interestingly, B6 can be used to treat the same issues it can cause. “Sometimes we use B6 in the right doses to treat neuropathy or nerve problems,” Gozansky says.

Vitamin B6 RDA

19–50 years old: 1.3 mg per day for men and women
50-plus years old: 1.7 mg per day for men, 1.5 mg per day for women

Overdose threshold

250 mg per day, long-term

The National Academy of Sciences Food and Nutrition Board says 100 mg per day is the recommended upper limit.

Foods with vitamin B6

Chickpeas
Beef liver
Tuna
Salmon

3. Vitamin D

Vitamin D is unique in that our bodies can make it when exposed to sunlight; we can also absorb it from the foods we eat.

“I often think of [vitamin D] not even so much as a vitamin, but I think about it as a hormone because it’s very important for muscle strength, it’s important for bones, it helps to regulate your parathyroid and your kidney function,” Gozansky says.

Some people have vitamin D deficiencies and need supplementation.

Gozansky recommends speaking with a doctor if you’re concerned that you are not getting enough vitamin D. “We can test for vitamin D levels in the blood to make sure that your storage level is the right amount,” she says.

Even though vitamin D is important for our health, too much can be dangerous, even deadly.

An adult shouldn’t exceed 100 mcg or 4,000 international units (IU) per day from food, drinks and supplements, according to NIH. Overdosing on vitamin D can cause a buildup of calcium in the blood, Gozansky says, which can cause confusion, dehydration, kidney stones, nausea and vomiting and lead to irregular heartbeat and death.

According to a paper published in BMJ Case Reports in 2022, a British man started a vitamin regimen on the advice of a private nutritionist and was taking 150,000 IU of vitamin D a day — 375 times the recommended amount in the U.K. For three months he experienced vomiting, nausea, abdominal pain, leg cramps, tinnitus, dry mouth, diarrhea and weight loss. By the time he was admitted to a hospital, his kidneys were failing. He was treated in the hospital for eight days; it took two months for his blood calcium levels to drop.

Vitamin D RDA

1–70 years old: 15 mcg (600 IU) per day for men and women
71 and up: 20 mcg (800 IU) per day for men and women

Overdose threshold

Take no more than the upper limit of 100 mcg (4,000 IU) daily from food, drinks and supplements unless under the direction of a physician to treat diagnosed vitamin D deficiency.

Foods with vitamin D

Rainbow trout
Sockeye salmon
Fortified milk

The body also makes vitamin D when exposed to sunshine.

4. Calcium

Calcium is a mineral that the body doesn’t produce on its own but is essential for bone health and movement. Calcium is often paired with vitamin D to boost absorption. And while consuming too much calcium through diet isn’t common, taking supplements can make it easy to overdo it.

Although our bodies are generally good at regulating the amount of calcium in our bloodstream, taking too much as a supplement can cause heart problems and kidney stones. Symptoms of calcium overdose include abdominal pain, nausea, vomiting, impaired kidney function, an increase in the pH of blood and more, according to the Mount Sinai Health System.

How much is too much calcium?

“Anything over 2,200 milligrams a day, we start worrying about having stomach upset or potentially predisposing people to kidney stones,” Gozansky says.

It’s important to know whether you’re consuming sufficient calcium quantities daily.

“I usually counsel patients on getting a total of 1,200 milligrams of elemental calcium per day,” Farrell says. “Everyone should be getting that, especially women as they approach and pass menopause because they’re at the highest risk for osteoporosis.”

Calcium RDA 

19–50 years old: 1,000 mg per day
51–70 years old: 1,000 mg per day for men, 1,200 mg per day for women
71-plus years old: 1,200 mg per day

Overdose threshold

The upper limit for people 19–50 is 2,500 mg per day.
The upper limit for people 51-plus is 2,000 mg per day.

Regular intake of more than 2,200 mg per day increases the risk of health problems.

Foods with calcium

Yogurt
Fortified orange juice
Mozzarella cheese

When You May Need a Vitamin or Mineral Supplement

Some people have health issues or deficiencies and supplements are warranted. For example, people who have had gastric bypass surgery may need to take supplements. And doctors often prescribe supplements to patients with macular degeneration since they may slow the progression of the disease.

People deficient in calcium or vitamin B12 may also need to supplement their diet. Be aware that many herbal remedies, vitamins and supplements can interact with medications, which can cause problems. The best course is to discuss any use of supplements or herbal remedies with your doctor.

5. Iron

The mineral iron is needed for development, growth and the production of some hormones. Most older adults don’t need additional iron, since iron deficiency is often associated with blood loss. “Taking an iron supplement in older age is not typical because we’re not losing blood normally,” Gozansky says.

Low iron can be a symptom of anemia or more concerning issues. A diagnosis of anemia can actually signal something very serious, Farrell says, especially in older adults.

“We as doctors tend to pursue pretty aggressively a workup of the [gastrointestinal] system to make sure they don’t have cancer,” Farrell adds.

He explains that doctors have to figure out what causes a person to be iron-deficient, since it’s uncommon for the condition to be caused by diet alone.

While an iron deficiency can signal and cause serious health problems, taking too much iron can also be dangerous.

An adult can take up to 45 mg of iron from supplements, food and drinks daily. Taking more is unsafe and can cause health issues, including diarrhea, vomiting and weakness, according to the Mount Sinai Health System. When selecting an iron supplement, the product label will list the tablet strength in milligrams and then the amount of iron in milligrams. For example, a ferrous sulfate 325 mg tablet contains 65 mg of iron, and both amounts are listed on the product label. Read that label carefully, or ask a pharmacist to help you select a product and decide how much to take.

“Too much iron actually can cause problems with the liver and the heart because it will deposit in the tissues,” Gozansky says.

Iron RDA

19–50 years old: 8 mg per day for males, 18 mg per day for females
51-plus years old: 8 mg per day for males, 8 mg per day for females

Overdose threshold

45 mg per day is the upper intake level for everyone over 14

Warning: Be careful not to leave iron supplements where children can get them. From 1983 to 2000, at least 43 children died from ingesting supplements with high doses of iron.

Foods with iron

Fortified breakfast cereals
Oysters
White beans
Beef liver
Lentils

6. Vitamin E

Vitamin E has several benefits, including immune system support and the regulation of inflammation. But too much may increase bleeding risk, particularly if you take blood thinners. Vitamin E can also interact with cholesterol-lowering medicines. Most people do not need a vitamin E supplement, experts say.

Vitamin E RDA

Adults should get about 15 mg per day

Overdose threshold

No more than 1,000 mg per day

Foods with vitamin E

Sunflower seeds
Almonds
Peanuts
Spinach

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Lauren David is a contributing writer who writes about food, gardening and health. Her work has appeared in The Washington Post, Dwell, Southern Living, marthastewart.com and other outlets.

Zachary Cox is a pharmacist and professor at Lipscomb University College of Pharmacy and adjunct professor at Vanderbilt University School of Medicine in Nashville, Tennessee.