Can You Die from Taking Too Many Vitamins? Doctors Weigh In

Although we frequently discuss the importance of working with your doctor to stay on top of—and try to prevent or remedy—deficiencies, there can be too much of a good thing when it comes to vitamin and mineral supplements. 

Just like eating too much protein and consuming too much fiber can throw your system for a loop, it is possible to overdo it on supplements, whether you pop them as pills, ingest them as powder shaken into water, or score them from fortified foods. (Or a mix of all of the above.)

“Vitamins and minerals are essential compounds found in nature that the body requires for its key functions, including metabolism,” explains William W. Li, MD, an internal medicine physician and scientist based in Boston and the author of Eat to Beat Your Diet. “Multivitamins are dietary supplements that contain multiple vitamins, and often minerals like calcium and iron, in order to make it convenient to get recommended doses into the body at once using one pill.”

Multivitamins are designed to supplement a balanced diet, not replace it. Typically, they provide up to 100% of the recommended daily value for each nutrient, which is adequate for most people, adds Patricia Bannan, RDN, a Los Angeles-based registered dietitian nutritionist and author of From Burnout to Balance.

“Although vitamins and minerals are essential for health, consuming them in excessive amounts can potentially lead to toxicity,” Bannan says.

What Causes Multivitamin Intoxication?

Although toxicity is rare, it’s possible—and according to Bannan, the risk of intoxication depends on three factors:

• The type of vitamins and minerals involved
• Their doses
• The duration of intake

Multivitamin intoxication is often the result of one of the following supplement mistakes:

Inappropriate Use of Vitamin Supplements

Regardless of whether you do it on purpose or accidentally, “if you take more than the recommended dosage, levels can build up in your body over time,” says Frances Largeman-Roth, RDN, a Dobbs Ferry, New York-based registered dietitian nutritionist and author of Everyday Snack Tray.

This is a fairly common cause of overdose, Bannan explains, as people might take more than the recommended dosage, “either by misreading labels or due to a misconception that more vitamins leads to better health.”

Taking High Doses of Specific Nutrients over a Prolonged Period

If you happen to consume extra water-soluble vitamins, like vitamin C and some B vitamins, your body is usually able to simply pee them out. 

“In fact, vitamins like B1, B2, B5, B7, and B12 are considered non-toxic and have no known upper limit because they can be easily eliminated,” Li says.

Still, certain water-soluble vitamins, including niacin (B3) and B6, can cause severe damage when taken in large amounts over time, Largeman-Roth adds, and very high intakes of vitamin C can cause diarrhea and vomiting. 

Most fat-soluble vitamins (think vitamins A, D, E and K) are a different story, and taking too many of them as supplements can be toxic. These vitamins are stored in your body’s tissue, meaning that high intakes can accumulate in your body’s fat, making them difficult to eliminate from the body, says Li.

The vitamins and minerals of greatest concern are:

• Vitamin A
• Vitamin D
• Vitamin E
• Vitamin K (although there is limited to no evidence of toxicity; the biggest issues arise among those who take certain medications, including blood thinners)
• Calcium
• Iron

Faulty Production or Labeling of Products

“Dietary supplements, including vitamin supplements, are not as tightly regulated as pharmaceuticals. This can lead to production problems like contamination or inaccurate dosing,” Li says. 

So, even if you follow the instructions listed on the package, you could inadvertently take too much of a vitamin or mineral, risking toxicity. (This can also lead to unexpected side effects—or no benefit at all.)

“This underscores the importance of buying from reputable sources and looking for third-party testing and certification,” Bannan says.

Always research your dietary supplement to make sure there are no complaints or FDA actions taken against the product, Li advises, which is a red flag and should steer you away from that product. And before you start taking any new supplement, be sure to consult with your doctor and only invest in products that are third-party tested.

Look for a seal on the label from a group like Consumer Lab, NSF International and US Pharmacopeia (USP). These are all trusted dietary supplement certification programs that companies can voluntarily submit their products for testing (and a stamp of approval that they do actually include what’s listed on the label, as well as nothing else that could be dangerous).

Can You Die from Multivitamin Intoxication?

Death from vitamin and mineral overdose is extremely rare. However, it can occur if someone consumes very high doses over a short period or consistently overdoses over a long period, according to Bannan. Extremely high doses of vitamin D, vitamin E, and iron, in particular, can be fatal, the experts we spoke to agree.

Usually, you’ll experience a series of symptoms first, which, if not treated, can waterfall into conditions like organ failure or bleeding in the brain before resulting in death.

Warning Symptoms of Multivitamin Intoxication

“The warning signs that someone might have multivitamin intoxication depends on the vitamin or mineral that has been overdosed,” Li says.

Here are the warning signs of potential overdose, according to our experts:

• Vitamin A: Vomiting, dizziness, blurry vision, abdominal pain, hair loss, joint pain, bone weakness, peeling skin, change in skin color to an orange hue, sleepiness, irritability, liver damage, a congenital disorder in a child born to a pregnant person taking too much
• Vitamin D: Irregular heartbeat, nausea, vomiting, weakness, seizures, confusion, unusual weight loss, formation of kidney stones, kidney failure, heart problems
• Vitamin K: Jaundice (yellowing of skin and eyes), anemia
• Vitamin E: Muscle weakness, gastrointestinal disturbances, emotional instability, bleeding, blood clots
• Calcium: Constipation, nausea, vomiting, confusion, impaired kidney function, irregular heartbeat
• Iron: Vomiting, diarrhea, fatigue, abdominal pain (and in severe cases, liver failure, intestinal bleeding, coma)

Diagnosis and Treatment

If you notice any of the symptoms mentioned above, or if you believe that you could have taken extreme amounts of certain vitamins or minerals, your doctor should be able to take a blood test to help pinpoint anything that may be “off.” From there, your medical care team can advise you about the best treatment plan, which almost always includes stopping supplements containing the vitamin or mineral of note.

How to Prevent Multivitamin Intoxication

If you follow these pro tips, vitamin and mineral toxicity will be extremely rare:

• Look for a seal that confirms third-party testing: To ensure that the product you’re consuming “actually contains what’s listed on the bottle and the strength and purity of the various vitamins and minerals listed,” Largeman-Roth says.
• Stick to the recommended dosage: “Look for the daily recommended values on the label, and don’t go beyond them in terms of dosing,” Li says. Your doctor should tell you how much to take when you get their thumbs-up before starting the supplement. If you are uncertain about how much to take, be sure to ask your primary health care provider.
• Don’t mix and match: Keep vitamins in their original bottle so it’s easier to track what they are and how much you’re taking, Li suggests.
• Aim to score your vitamins and minerals through food: It can be difficult for individuals with certain diets, such as veganism, to eat enough of certain vitamins and minerals through food. Some medical deficiencies can necessitate supplementation as well. Still, according to Li, your best bet is to “get your vitamins through food, like whole plant-based foods, seafood, and meat. This can get you what you need,” he says. Only use multivitamins as a “supplement” to top off what you are not getting through diet. 
• Watch for sneaky sources: If you’re taking a multivitamin and other supplements, look for other products, such as energy bars, energy drinks, or shakes, that may also contain vitamins and minerals, Largeman-Roth advises.

The Bottom Line

Taking too many vitamins and minerals is a very infrequent issue, but it can happen. And with certain vitamins and minerals, it can be dangerous or even fatal. 

For this reason, it’s crucial that “before starting any new supplement, consult with a doctor or a registered dietitian, especially if you have underlying health conditions or take other medications,” Bannan says.