Are multivitamins worth taking?

For the average healthy adult, the evidence does not support the habit. The NIH's review of multivitamin/mineral research finds studies too inconsistent to compare - different products, different formulas - and no reliable proof they prevent chronic disease; it also notes people who take multivitamins often already get more vitamins from food than non-takers, meaning the healthy were self-selecting all along. The insurance-policy logic ('it cannot hurt') mostly holds for harm, but it is not airtight: more is not neutral for fat-soluble vitamins A, D, E, and K, which accumulate, and high-dose beta-carotene has shown harm in smokers. Where multivitamins earn their shelf space: pregnancy (folic acid prevents neural tube defects), adults over 50 (B12 absorption drops with age), restricted diets (vegan, very low calorie), bariatric-surgery patients, and anyone with a documented deficiency. The practical read: a standard once-daily multi is a cheap, safe safety net for a patchy diet - just do not expect it to compensate for one, and do not stack a multi on top of single-nutrient pills without checking the totals. Pymander is a free AI doctor, 24/7 by text, that can help you audit your stack.