Best Time to Take Vitamins: Morning, Night or With Food?

For most vitamins, the best time to take them is the time you'll remember. The NIH Office of Dietary Supplements (ODS) says the time of day you take supplements doesn't usually matter. Three things matter more than the clock: whether you take a supplement with food, what you take it with, and how far apart you keep it from certain medicines. This article covers each one, with links to our supplement pages for the details. It's part of our guide to never missing a dose.

This is general information, not advice for your situation. Your doctor or pharmacist can tell you how to time supplements with your medicines.

Does the Time of Day Matter?

Usually not. In its February 2024 consumer bulletin, the ODS answered this question directly: time of day doesn't usually matter, so find a time that works for you. It then named the exceptions that do matter:

• Food: many supplements, including vitamin D and fish oil, are better absorbed with a meal.
• Pairings: taking iron with a drink containing vitamin C can increase absorption, while taking iron at the same time as calcium can hinder it.
• Medicines: some supplements can interfere with how medicines are absorbed, so if you take any, ask your health care provider whether to take them at different times.

So "morning or night" is mostly a question of habit. For a multivitamin, a time you'll keep every day, like breakfast, matters more than finding a perfect hour. The rest of this article covers the exceptions.

Which Vitamins to Take With Food

Fat-soluble vitamins (A, D, E and K) are absorbed together with dietary fat, according to a 2024 clinical review of these vitamins. So take vitamin A, vitamin E, vitamin K2 and vitamin D with a meal that has some fat in it.

For vitamin D specifically, the ODS health professional fact sheet says that fat in the gut at the same time improves absorption, though some vitamin D is absorbed even without dietary fat. The ODS also lists fish oil among the supplements better absorbed with a meal, which includes fish oil omega-3 supplements.

Calcium depends on its form. The ODS consumer fact sheet says calcium carbonate is absorbed best with food, while calcium citrate is absorbed well on an empty or a full stomach. Check the label to see which one you have.

Water-soluble vitamins (the B vitamins and vitamin C) don't depend on dietary fat, so vitamin B12 and vitamin C can go wherever fits your routine.

Iron and Calcium: Take Them Apart

Iron and calcium shouldn't go down at the same time. The ODS iron fact sheet says calcium might interfere with iron absorption, and that taking calcium and iron supplements at different times of the day might prevent the problem.

In practice that often means iron at one meal and calcium at another, for example iron with breakfast and calcium with dinner. Multivitamins and prenatal vitamins can contain iron, calcium or both, so check the label before you add a separate iron or calcium tablet on top.

Vitamin C works the other way. The ODS vitamin C fact sheet says vitamin C improves the absorption of iron from plant foods, and the ODS bulletin notes that an iron supplement taken with a vitamin C drink, such as orange juice, can be absorbed better.

If you were prescribed iron, follow the timing on your prescription. It may differ from general supplement advice.

Vitamins and Thyroid Medicine

If you take levothyroxine, this is where supplement timing matters most. MedlinePlus says levothyroxine is usually taken once a day on an empty stomach, 30 minutes to an hour before breakfast. It also says that if you take calcium carbonate or ferrous sulfate (iron), you should take them at least 4 hours before or 4 hours after levothyroxine.

The ODS iron fact sheet makes the same point from the supplement side: iron taken with levothyroxine can make the medicine less effective. It says the same about levodopa, a Parkinson's medicine.

On thyroid medicine, that can mean moving iron and calcium to lunch or dinner. Your pharmacist can confirm the right gap for your prescription, and our hypothyroidism routine page covers how to set reminders around it.

Magnesium, Zinc and Antibiotics

Magnesium and zinc both need spacing from some antibiotics. The ODS magnesium fact sheet says magnesium can bind to tetracycline antibiotics, such as doxycycline, and to quinolones, such as ciprofloxacin. It advises taking these antibiotics at least 2 hours before or 4 to 6 hours after a supplement containing magnesium. The ODS zinc fact sheet gives the same window for zinc with the same two antibiotic groups, because each can reduce how much of the other the body absorbs.

Magnesium also needs a gap from oral bisphosphonates, osteoporosis medicines such as alendronate. The ODS advises taking magnesium at least 2 hours before or after them.

If you're prescribed one of these antibiotics while taking zinc or magnesium, the simplest option is to tell your pharmacist what you take. They'll tell you whether to space the supplement or pause it for the length of the course.

Melatonin: When Timing Is the Point

Melatonin is the exception where timing is the whole idea. Most supplements in this article only care about meals and pairings, but melatonin is used to shift when you fall asleep.

The National Center for Complementary and Integrative Health (NCCIH) describes a 4-week study in people with delayed sleep-wake phase disorder. Taking melatonin 1 hour before the desired bedtime, together with going to bed at a set time, led to several improvements. NCCIH also says research suggests melatonin may help with jet lag.

Two cautions from the same source. In the United States, melatonin is sold as a dietary supplement, so it's regulated less strictly than medicines. And parents should speak with a health care provider before giving melatonin to children. Our melatonin page covers how to set an evening reminder for it.

A Simple Way to Schedule Several Supplements

Group supplements by meal, then move the ones that can't share. For someone taking a few common supplements and no interacting medicines, a schedule might look like this:

This is an example, not a prescription. If you take levothyroxine, antibiotics, bisphosphonates or other medicines, ask your pharmacist to check the plan first.

Once you've got a schedule, the hard part is sticking to it. Give each meal slot one reminder, rather than one per pill. Our guide to tracking vitamins and supplements covers how to keep a record, and tracking morning, afternoon and evening medications shows how to group doses by time of day. If any of your supplements go twice a day, see our twice-daily routine guide.