Multivitamin

What it does

A multivitamin supplies reference-level doses of common micronutrients (A, C, D, E, B vitamins, zinc, magnesium, and others) in one pill, intended to fill gaps when diet falls short.

What the research says

• Small cognitive benefits in older adults

  Evidence: moderate. COSMOS sub-studies reported modest global cognition and episodic memory benefits in older adults, strongest in those with cardiovascular disease.

• Slower epigenetic aging markers

  Evidence: emerging. COSMOS biomarker analysis (Nature Medicine, 2026) found roughly four months less biological aging over two years versus placebo.

• Reduced colorectal cancer risk

  Evidence: weak. Jan 2026 Ageing Research Reviews meta-analysis noted a colorectal signal, but no benefit for all-cause mortality, COVID-19 outcomes, or other cancers.

The biggest randomized data (COSMOS) found no benefit for cancer, cardiovascular events, or mortality in healthy adults; the 390,000-person 2024 cohort analysis found no mortality benefit. Real but modest signals exist for cognition in older adults and epigenetic clocks, all secondary or emerging.

What the experts say

Every position links to its source. We include skeptics alongside supporters.

• Howard Sesso

  “A lot of people take a multivitamin without necessarily knowing any benefits from taking it, so the more we can learn about its potential health benefits, the better.”

  Source, 2026-03-12 Principal investigator of COSMOS; presented the 2026 epigenetic-aging findings as promising but preliminary, and stressed learning what benefits actually exist before recommending use.

• Tim Spector

  “People pop a multivitamin and carry on eating rubbish.”

  Source, 2024-06-30 Critical; calls most supplements a complete waste of money and says 99 per cent have no evidence they work, including the daily multivitamin habit.

• Rhonda Patrick

  “I'm taking vitamin D with K2 and the ONE Multivitamin by Pure Encapsulations.”

  Source Takes the ONE Multivitamin by Pure Encapsulations daily as part of her core routine, noting it includes zinc and other micronutrients.

Is it worth it?

Cheap, but the evidence of benefit in well-nourished adults is weak and population-dependent. Worth considering mainly as gap insurance for people with confirmed dietary gaps, deficiencies, or pregnancy, not as a longevity driver.