Is it Safe to Take Multivitamins With B-Complex Vitamins?

Can You Take Multivitamins With B-Complex Vitamins?

Can You Take Multivitamins With B-Complex Vitamins?
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Updated on August 6, 2025
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Multivitamins often provide 100 percent of the daily value for most B vitamins, so you probably don’t also need to take a B-complex supplement. Because B vitamins are water-soluble, they don’t build up in your body — what you don’t need gets removed through your urine. Most don’t have a toxic level.

However, if you eat a fortified cereal at breakfast, grab an energy bar between meals, have enriched pasta for dinner, or take a niacin-based medication along with a B-complex and multivitamin supplement, you might be taking more B vitamins than you need.

While you’re unlikely to have ill effects from taking both multivitamins and B-complex together, certain B vitamins can cause dangerous symptoms if you take them at very high levels and can interact with medications and interfere with some lab tests.

Vitamin B3

Vitamin B3, also called niacin, helps convert food into energy and is important for your nervous and digestive systems.

 The recommended daily amount of niacin is 16 milligrams (mg) for men and 14 mg for women, with the upper limit being 35 mg per day.

You may be prescribed much higher amounts as a treatment for high cholesterol or if you have a niacin deficiency. But you should never exceed the upper limit for B3 unless it’s under your doctor’s supervision.

Vitamin B3 toxicity is rare, but a combination from food sources, herbal supplements, health bars, and niacin-based medications, in addition to multivitamins and B-complex vitamins, may have negative effects on your health.

Too much B3 can cause:

  • Skin flushing
  • Dizziness
  • Fatigue
  • Itching
  • Nausea
  • Vision changes
  • High blood sugar
  • Liver damage

B3 can also interfere with certain medications, so check with your doctor before you take a B-complex supplement.

Vitamin B6

Vitamin B6, also called pyridoxine, helps your body convert food into energy and is responsible for normal brain function and development as well as the production of red blood cells.

 The recommended daily intake is 1.3 to 2 mg for adults. The National Academy of Medicine has set the safe upper level at 100 mg, while the European Food Safety Authority says it’s just 12 mg a day.

You could exceed that if you take both a multivitamin and a B-complex supplement. It’s in food like fortified cereal, and some energy drinks have extremely high levels.

Too much B6 can cause serious symptoms, including:

  • Nerve damage, including pain, tingling, and numbness in your hands and feet
  • Trouble walking or controlling your movements
  • Nausea and heartburn
  • Sensitivity to sunlight
  • Skin damage
B6 supplements can interfere with how well certain medications work, so talk with your doctor if you take altretamine (for chemotherapy), barbiturates, anticonvulsants, or levodopa (to treat Parkinson’s disease).

Vitamin B9

Also called folate, vitamin B9 helps your body make DNA and is necessary for cell division. Because it’s critical for the development of a fetus’s brain and spinal cord, it’s recommended that anyone who could become pregnant take 400 micrograms (mcg) a day — 600 mcg if you are pregnant.

Taking folate above the safe upper limit of 1,000 mcg may cause health problems. It can disguise the symptoms of a vitamin B12 deficiency, which if untreated can cause nerve damage. It may also increase your chances of developing colon or rectal cancer.

The Takeaway

  • Most B vitamins are safe at high doses, so it’s unlikely you’ll have problems if you take both a multivitamin and a B-complex supplement.
  • B3, B6, and B9 can be dangerous at very high levels or in combination with certain prescription medicines, so always check with your doctor before taking a supplement.
  • Unless you’re diagnosed with a vitamin or mineral deficiency, a balanced diet is all most people need to get the recommended amount of vitamins every day.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Curely J et al. Water-Soluble Vitamins: B-Complex and Vitamin C. Colorado State University Extension. August 2025.
  2. Niacin. Mayo Clinic. March 21, 2025.
  3. Niacin. National Institutes of Health Office of Dietary Supplements. March 22, 2021.
  4. Peechakara BV et al. Vitamin B3. StatPearls. February 29, 2024.
  5. Top 7 Benefits of Vitamin B6. Cleveland Clinic. December 30, 2022.
  6. Vitamin B6. National Institutes of Health Office of Dietary Supplements. June 16, 2023.
  7. Barratt D et al. 7 Cases of Vitamin B6 Toxicity (P11-2.001). Neurology. April 8, 2025.
  8. Vitamin B-6. Mayo Clinic. August 13, 2025.
  9. Folate. National Institutes of Health Office of Dietary Supplements. November 1, 2022.
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Natalia Johnsen, MD

Medical Reviewer
Member of American College of Lifestyle Medicine

Natalia Johnsen, MD, practices internal medicine and lifestyle medicine. She works as an internist for the Vancouver Clinic in Vancouver, Washington.

Johnsen trained and worked as ob-gyn in Russia before coming to the United States in 2000. Subsequently, she interned in internal medicine at the University of Nevada and completed her residency at a Stanford-affiliated program in Santa Clara, California. After that she worked as a general internist for two years before to switching to full-time hospital work.

Johnsen has always been fascinated by the effects that lifestyle can have on physical and mental health, and she fell in love with the concept of lifestyle medicine as a specialty after seeing patients struggle with issues that could have been prevented had they known more about a healthy lifestyle. To make an impact on her patients through lifestyle interventions, she launched her own lifestyle medicine clinic, Vivalso Health and Longevity.

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Gord Kerr

Author

Gordon Kerr has worked in the health care industry for the past 15 years. He holds a diploma in Food and Nutritional Science from CSNN, Canadian School of Natural Nutrition, Vancouver. With his passion for a healthy lifestyle and the desire to help others benefit from proper nutrition and natural remedies, Gordon accepted the international position with CARICOM Regional Food and Nutrition in the Caribbean and moved to Barbados. As well as educating the under-nourished people in the region, Gordon formulated dietary plans to help manage medical conditions including chronic nutrition-related diseases, such as diabetes and hypertension. Now retired, Gord enjoys a quiet life on a small island in the Gulf Islands of B.C.

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