What Time of Day Should You Take a Multivitamin — and These 4 Other Supplements?

Note: The U.S. Food and Drug Administration (FDA) does not approve supplements for safety or effectiveness. Talk to a healthcare professional about whether a supplement is the right fit for your individual health, and about any potential drug interactions or safety concerns.

If you take dietary supplements, it can matter when you take them — and whether or not you consume them with food or other supplements.

“Some nutrients can actually prevent or improve the absorption of others,” says Jeremy O’Neal, RDN, of the University of Illinois Health Bariatric Surgery Program in Chicago.

Consistency can also be important. For example, what time of day you pop a multivitamin really doesn’t matter — but taking it around the same time every day can be beneficial, and having it with a little food and water can help you maximize absorption and avoid digestive issues.

Here’s when to take several common dietary supplements — and when not to, according to nutrition experts.

While a daily multivitamin can be consumed at any time of day, consistency is key, and having it with a little food or water can help, says Doug Cook, RD, a coauthor of Nutrition for Canadians for Dummies and host of the Pursuit of Health podcast, based in Toronto.

“What matters is taking supplements consistently, in a way that works for you,” Cook explains.

Taking a multivitamin around the same time each day helps ensure a stable level of nutrients. While the body does store some nutrients, many, like vitamin C, are short-lived and water-soluble (meaning they are not stored in the body and excess is excreted in your urine), O’Neal says.

Keep the 80/20 rule in mind: “Eighty percent of the time, be consistent with taking a daily multivitamin,” says O’Neal. “But if you forget to take it, say, 20 percent of the time, it’s not the end of the world.”

A daily multivitamin may provide nutrient insurance — especially if you have certain conditions that put you at risk of deficiencies. “For an otherwise healthy person, food is the best source for these vitamins and minerals,” says O’Neal. “The exception to this includes anyone who is post–bariatric surgery or has other malabsorption concerns,” he adds.

Multivitamins may also be helpful for people taking a GLP-1 medication for obesity and weight loss. “GLP-1 medications often decrease food intake, and if [you’re] experiencing vomiting, may lead to thiamine and other B vitamin deficiencies in the long term,” says O’Neal.

O’Neal suggests splitting your vitamin C supplement into two smaller doses and taking it twice daily, instead of one large dose, because your body doesn’t store this water-soluble vitamin for long. “With vitamin C, what comes in always goes out,” he explains. “Any excess that isn't utilized by the body's metabolism is then passed through the urine.”

For the standard dose of over-the-counter vitamin C — about 1,000 milligrams (mg) per serving — O’Neal recommends dividing the serving size in two: 500 mg in the morning and 500 mg in the p.m. hours.

In some cases, your doctor may recommend you take a vitamin C supplement. “There’s not a great blood test that accurately shows vitamin C levels in the body, since the body can’t store it,” says O’Neal. “But [taking] vitamin C supplements are like an insurance policy for health. It may not prevent disease, but it may lessen the overall inflammation if it’s present.”

“Fat helps with the body’s secretion of bile, which you need for maximal absorption [of these nutrients],” Cook says. He recommends snacking on almonds or toast with peanut or nut butter.

“I would recommend iron for those diagnosed with a deficiency or malabsorption concern, or eating an iron-deficient diet, such as with a vegan diet or someone who had bariatric surgery,” says O’Neal.

• If you take supplements, the timing of when you do so may impact their absorption or how you feel after. For instance, you can pop a multivitamin any time of day, but taking it consistently with food and water can prevent tummy trouble and boost absorption.
• Consider taking vitamin C in two smaller doses — once in the morning and once in the afternoon — rather than in one larger dose, to avoid losing excess through excretion.
• Pair fat-soluble vitamins like A, D, E, and K with dietary fat, which help your body secrete bile that’s necessary for efficient absorption. Calcium and iron are also best taken with some food.
• Many dietary supplements interact with medications, so always speak to your doctor before taking them.