A multivitamin is a daily supplement that packages essential vitamins and minerals together in one convenient dose. Most people — even those eating a reasonably healthy diet — have at least one or two nutrient shortfalls, and multivitamins are designed to catch those gaps before they cause problems. They are one of the most widely used supplements in the world, taken by roughly one-third of adults in the United States alone.

Your body runs on micronutrients — vitamins and minerals that power everything from energy production and immune defense to DNA repair and hormone balance. When even one of these is consistently low, you may feel it as fatigue, brain fog, poor immunity, or slow recovery. A multivitamin delivers a broad spectrum of these nutrients in one dose, helping maintain the baseline your body needs to function well every day.

Tablets and capsules are the most common and typically the most nutrient-dense per dose. Gummies are popular but often lower in iron and may contain added sugars. Liquids and powders can absorb quickly and are useful for those who have trouble swallowing pills. Effervescent tablets dissolve in water and tend to use smaller, absorbable doses. Choose the form you will consistently take — adherence matters most.

improves emotional regulation improves immediate memory reduces aggression reduces inattention

• Neural tube defects in pregnancy (folic acid/folate — strong evidence)
• Vitamin D deficiency-related bone loss and fracture risk
• Progression of age-related macular degeneration (AREDS2 formula)
• Nutritional deficiency in older adults with reduced dietary variety
• Micronutrient gaps in people following restrictive diets (vegan, low-calorie)

• Leafy greens (spinach, kale, Swiss chard) — Rich in folate, vitamin K, vitamin A, vitamin C, magnesium, and calcium — covering several of the most commonly deficient micronutrients in one food group.
• Eggs — A natural source of vitamins A, D, B2, B12, biotin, and selenium — delivering several fat-soluble vitamins in a highly bioavailable form.
• Beef liver — Arguably the most micronutrient-dense food on earth — exceptionally high in B12, folate, vitamin A, iron, copper, and zinc, matching or exceeding many multivitamin doses in a single serving.
• Fatty fish (salmon, mackerel, sardines) — Outstanding source of vitamin D, B12, selenium, and omega-3 fatty acids — directly addressing several of the most common modern nutritional shortfalls.
• Legumes and fortified whole grains — Provide B vitamins (especially folate and B1), iron, magnesium, zinc, and selenium — making them an important base for a micronutrient-rich plant-forward diet.

Multivitamins are generally well tolerated

• Recommended daily: One serving daily as directed on product label — typically 1–2 tablets or capsules delivering nutrients at or near 100% of the Daily Value for most vitamins and minerals. Prenatal formulas and therapeutic multivitamins may differ.
• Best time of day: Morning is ideal for most people — B vitamins support energy metabolism and can be stimulating if taken in the evening. If your multivitamin contains melatonin or calming herbs, evening may be appropriate.
• With or without food: Always take with a meal containing some fat. Fat-soluble vitamins (A, D, E, K) require dietary fat for proper absorption, and food reduces the nausea that iron and B vitamins can cause on an empty stomach.
• Time to effect: Noticeable improvements in energy, mood, or immunity typically appear within 2–6 weeks of consistent use. Correcting a significant deficiency may take 3–6 months of daily supplementation.
• How long to take it: Safe for continuous daily use long-term in healthy adults. No cycling required. Revisit your formula periodically — needs change with age, pregnancy, menopause, and health status. Annual bloodwork helps confirm whether your multivitamin is actually filling your gaps.