Multivitamins: Good for You or Not? Experts Weigh In

Some experts say taking a daily multivitamin is a waste of time, but others say they have value. What should you do?

When it comes to health, many people swear by vitamins as a part of their wellness regimen, and I’m one of them. If I go too many days without my multivitamin, I feel tired. But research shows that taking a multivitamin may not do what you expect. There is not a lot of evidence that shows your vitamin and mineral cocktail is the panacea for the healthy lifestyle you seek. In the majority of studies, there is no benefit from multivitamins in protecting the brain or heart. But there is optimism from experts at Harvard.

“There are potential benefits and there are no known risks at this time,” says Dr. Howard Sesso, an associate professor of epidemiology at the Harvard School of Public Health. “It is worth considering a multivitamin as part of a healthy lifestyle.”

If you really believe your multivitamin aids in your well-being, but expert opinions seem to differ, what do you do? First, ask yourself why you take a multivitamin.

What the Experts Know About Multivitamins

There have been numerous studies on vitamins and health, but only a small percentage of thorough research on the benefits of a “true” multivitamin, a capsule that has all the crucial vitamins and minerals at reasonably low levels that are essential to our bodies.

The best study done thus far is the Physicians’ Health Study II. This was the first and only large-scale randomized clinical trial to test a commonly taken multivitamin like the ones in your local drug stores, containing the daily requirements of 31 vitamins and minerals essential for good health.

A sizeable number of male physicians took either a multivitamin or a placebo pill for more than a decade. The findings were mixed, with modest reductions in cancer and cataracts, but no shielding effect against cardiovascular disease or diminishing mental function. What about safety?

According to multivitamin advocates, there is no strong evidence that taking a multivitamin for many years is harmful. “While I agree that the likelihood of harm is small, the likelihood of a clear health benefit is also very small—and also we have no clear proof yet of such benefit,” says Dr. Guallar, a scientist at the Johns Hopkins Bloomberg School of Public Health.

Dr. Sesso speaks for the optimists, who urge a wait-and-see approach. “Multivitamin supplementation is low risk and low cost, and it helps to fill potential gaps in the diet that people might have,” Dr. Sesso says. “These are compelling reasons to consider taking a multivitamin for cancer and eye disease that should be discussed with your physician.”

Findings From the Multivitamin Study

Physicians’ Health Study II

Researchers looked at the effect of long-term multivitamin use in healthy men on various aspects of health. Here is what they found:

Cancer: Men were 8% less likely to be diagnosed with cancer. The protective effect was greatest in men with a history of cancer.
Vision: Lower risk of developing cataracts.
Cardiovascular disease: No protection against heart attacks, strokes, or death from cardiovascular disease.
Brain: No protection against declining memory or mental skills.
Be advised: Because of PHSII’s design, the findings on memory loss and vision are somewhat more likely to be chance findings than cancer and cardiovascular disease results.

For now, you can take certain steps:

Ask your doctor if you have a vitamin deficiency and if you actually need to take a multivitamin.
Assess your diet to see if anything is absent. Could you eat healthier?
Seek a dietitian for expert nutritional advice.
Taking high doses of specific vitamins can be harmful, such as A and E. Do your research!
If you are a Medicare beneficiary, get an annual “wellness” visit with your primary care provider.

The long and the short of multivitamins is this: if, after you do your research, you believe you need a vitamin, then do what makes you feel best.

Multivitamins FAQ

What Are Multivitamins?

Multivitamins are supplements that contain a combination of vitamins and minerals, and sometimes other ingredients like herbs or amino acids. They’re designed to fill nutritional gaps and support overall health.

How Do They Work?

1. Absorption in the Digestive System

Once you swallow a multivitamin:

It travels to your stomach, where it starts breaking down.
In the small intestine, the nutrients are absorbed into the bloodstream.
From there, nutrients are transported to tissues and organs that need them.

2. Supporting Body Functions

Each vitamin and mineral in a multivitamin plays a unique role:

Vitamin A – supports vision, immune function, and skin health.
Vitamin C – helps with collagen production, immunity, and iron absorption.
Vitamin D – promotes calcium absorption and bone health.
B vitamins (like B6, B12, folic acid) – support energy production and brain function.
Iron – helps transport oxygen in the blood.
Calcium and Magnesium – essential for bone and muscle function.

These nutrients often act as coenzymes or cofactors that help enzymes function properly in the body.

3. Filling Nutritional Gaps

If your diet lacks certain nutrients—due to restrictions, health conditions, or lifestyle factors—multivitamins help prevent deficiencies. For example:

Vegans may benefit from B12.
People with limited sun exposure might need more Vitamin D.
Pregnant individuals may need folic acid and iron.

Do You Need a Multivitamin?

It depends. You may benefit if you:

Have dietary restrictions (vegan, vegetarian, etc.)
Are over age 50
Are pregnant or trying to conceive
Have certain health conditions or nutrient deficiencies
Don’t eat a balanced diet

But if you already eat a nutritious diet, multivitamins may not make a significant difference.

Important Notes

More isn’t better: High doses of certain vitamins (like A, D, E, and iron) can be toxic.
They don’t replace a healthy diet: Whole foods provide fiber and other compounds that supplements can’t.
Check with your doctor: Especially if you’re on medications or have health conditions.

By Giselle Brownlow | Published August 6, 2025