Multivitamins are the world’s most popular supplement — but do they actually work, or are they expensive insurance against a balanced diet? StudyFinds has covered dozens of peer-reviewed studies on vitamins, minerals, and supplements. This guide pulls together the most important findings: what the evidence says about multivitamins, which specific vitamins are backed by science, what risks to watch for, and where supplements genuinely help vs. where food wins.

Do Multivitamins Actually Work?

Vitamins & Specific Health Benefits

Vitamins for Kids & Families

The Risks: What to Watch Out For

Vitamins for Hair, Skin & Beauty

Frequently Asked Questions About Multivitamins

Should I take a multivitamin every day?

The evidence is mixed. Large studies show multivitamins don’t reduce risk of heart disease or cancer in well-nourished adults, but research does suggest they may help slow cognitive aging. Most experts say a balanced diet is the priority — but a basic multivitamin is low-risk insurance if your diet is inconsistent.

Which vitamins are most important?

Vitamin D is the most studied and most commonly deficient, linked to immune function, bone health, and dementia risk. Vitamin C, B vitamins (including folate and B12), and omega-3s also have strong research backing for specific populations. See the studies above.

Are multivitamins safe?

For most healthy adults, yes — at standard doses. The risks come from megadosing fat-soluble vitamins (A, D, E, K) or certain herbal supplements linked to liver damage. Calcium supplements may not prevent falls and carry their own risks. Always check with a doctor if you take medications.

Do children need multivitamins?

Not automatically. Research suggests most kids eating a varied diet don’t need daily multivitamins — and some vitamins can be harmful at high doses in children. Vitamin D is the exception: deficiency in kids is common and is linked to slower healing and development. See the studies above for specifics.