Multivitamins in Adult Medical Practice: Evidence, Risks, and Pragmatic Prescribing.

Use of multivitamin-mineral supplements is common and often occurs outside clinical care. Evidence for broad preventive benefit remains uncertain. We synthesize validated indications, clinical benefits, and harms, and offer a pragmatic prescribing approach for internists. Narrative review of guidelines, randomized trials, and meta-analyses indexed in major databases (2000-August 2025). Priority was given to high-level evidence on hard outcomes (all-cause mortality, cardiovascular events, cancer incidence/mortality, cognition) and to conditions frequently managed in Internal Medicine (malabsorption, bariatric surgery, alcohol use disorder, aging, restrictive diets). This is not a systematic review. Multivitamins are justified for documented deficiencies or high-risk states, including malabsorption, post-bariatric surgery, chronic alcohol use, pregnancy/lactation, and frailty. In generally nourished adults, multivitamins do not reduce cardiovascular events or mortality, and evidence for cancer prevention is marginal without a mortality impact. Recent data suggest small cognitive benefits in older adults. Risks include hypervitaminosis A/D/E, clinically relevant drug-nutrient interactions, masking of specific deficiencies, behavioral displacement of diet-first strategies, and unnecessary cost. Outside of deficiency or clearly increased need, routine multivitamin prescribing provides little clinical gain and exposes patients to avoidable harms. Internists should screen, test, and treat specifically, prefer targeted nutrients, monitor safety, and educate patients against overreliance on supplements.