Multivitamin
Content by: OpenSupplement Editorial Team | Medical review: pending | Last updated: April 13, 2026
TL;DR
Comprehensive vitamin and mineral blend for nutritional insurance
Mixed evidence for healthy adults eating varied diets
May benefit those with dietary restrictions or absorption issues
Quality varies dramatically between brands
Some nutrients compete for absorption when taken together
Best for: dietary gaps, restrictive diets, pregnancy, older adults
What it is
Multivitamins are supplements containing a combination of vitamins and minerals, designed to provide a broad spectrum of essential nutrients in a single product. They typically include fat-soluble vitamins (A, D, E, K), water-soluble vitamins (B-complex, C), and essential minerals like calcium, magnesium, zinc, and iron.
The concept is 'nutritional insurance' - covering potential gaps in the diet. However, the effectiveness of multivitamins for healthy adults eating varied diets remains scientifically controversial, with major studies showing mixed results.
What the research says
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Multivitamin on Amazon
Safety
Multivitamins are generally well-tolerated, though several considerations exist. Fat-soluble vitamins (A, D, E, K) can accumulate and potentially reach toxic levels with excessive intake. Iron-containing formulations may cause stomach upset and can be dangerous for individuals with hemochromatosis.
Some nutrients compete for absorption (calcium and iron, zinc and copper), potentially reducing effectiveness. High-dose formulations may exceed safe upper limits for certain nutrients, particularly in synthetic forms.
Interactions
• Antibiotics (tetracyclines, quinolones): Take 2+ hours apart due to mineral interference • Thyroid medication (levothyroxine): Take 4+ hours apart, particularly iron and calcium • Blood thinners (warfarin): Vitamin K content can affect INR levels • Proton pump inhibitors: May increase need for B12 and magnesium • Diuretics: May increase need for potassium and magnesium
Dosing
General adults: One daily serving as directed, typically with breakfast for better absorption and reduced stomach upset
Pregnancy: Prenatal formulations with higher folate and iron
50+ adults: Senior formulations often exclude iron and include higher B12
Athletes: May benefit from higher B-vitamin content
Taking with food improves absorption and reduces gastric irritation.
Cost
Multivitamins range dramatically from $8-40 monthly. Basic store brands provide adequate nutrient coverage for $8-15/month. Premium brands with better forms (methylated B-vitamins, chelated minerals) cost $20-40 monthly. Third-party testing adds value given quality control issues in the supplement industry. Price doesn't always indicate quality - some expensive brands have poor bioavailability.
The bottom line
Multivitamins are a reasonable 'insurance policy' for those with dietary restrictions, absorption issues, or inconsistent eating patterns, despite mixed evidence for healthy adults with varied diets. They're unlikely to harm and may help fill genuine nutritional gaps. The key is choosing quality brands with appropriate doses and bioavailable forms rather than megadose formulations that often provide nutrients far exceeding needs.
References
- Office of Dietary Supplements - National Institutes of Health. Multivitamin/mineral Supplements. Updated March 29, 2021.
- Jenkins DJA et al. Supplemental Vitamins and Minerals for CVD Prevention and Treatment. J Am Coll Cardiol. 2018;71(22):2570-2584.
- Fortmann SP et al. Vitamin and mineral supplements in the primary prevention of cardiovascular disease and cancer: An updated systematic evidence review for the U.S. Preventive Services Task Force. Ann Intern Med. 2013;159(12):824-834.
Sources for this page include published meta-analyses, systematic reviews, and NIH dietary supplement fact sheets. All claims reflect the evidence as of early 2026.
This is not medical advice. Consult your healthcare provider before starting any supplement, especially if you take medications.