When Is the Best Time to Take Vitamins?

So you’ve figured out exactly what supplements you should be taking to meet your health goals (whether you’re prioritizing fertility, gut health, or overall wellness)—but now you’re staring at them, wondering when to take what. Morning? Night? With food? Without? You’re not alone. Timing can make a difference for certain nutrients, so when is the best time to take vitamins? Here’s your no-stress guide to getting the most from your supplements.

First, let’s talk about the most important thing: consistency. The nuances of when to take your vitamins are important, but what really makes the biggest difference is taking your supplements daily. Consistency over time is key; this is especially true during the prenatal period when we want to ensure certain nutrient stores (like Folic Acid, Vitamin D, and Iron) are being built and maintained. The best time to take your supplements daily is when it’s easiest for you to remember! (Have trouble remembering? Set an alarm on your phone to remind you daily—you may remember this trick from the pill, if you were on it.)

Another helpful tip: take your prenatal vitamins with a meal. This helps to reduce unwanted side effects (like nausea) and to improve absorption. 

Midday is a good time to take those tricky vitamins that have known interactions with food, or other vitamins, and need to be taken on their own. Iron is notoriously hard to absorb, and there are important nutrient and food interactions that further decrease its absorption and bioavailability. (More on this later.) 

• Ease gut irritation
• Prevent nausea
• Increase absorption, especially of fat-soluble vitamins

There are certain vitamins and nutrients that ideally should be taken away from each other. One of the best examples of this is Iron and Calcium. Calcium acts as a non-competitive inhibitor at the transporter required for Iron absorption, which means it can impact how well Iron is absorbed if its taken too close in time to Calcium. The important thing here is that the effect is dose-dependent. Less than 800 mg of Calcium at a time doesn’t show a significant impact on the absorption of Iron, so if your doses are lower, you don’t need to stress too much. But, to be safe, taking Iron 2 hours away from Calcium supplements, antacids, fiber supplements, and thyroid medication can help to improve absorption. Conversely, Vitamin C supplementation at 250 to 500 mg can improve Iron absorption! Look for an Iron supplement that contains Vitamin C, or take your Iron with a swig of orange juice.

The Iron advice holds here too, since many of us get most of our Calcium from our diets. If you’re eating Calcium-rich foods (like dairy products), make sure they’re consumed apart from your Iron supplement.

The other big one? Coffee and tea. Caffeine inhibits Iron absorption. The American Gastroenterological Association recommends that tea and coffee, which contain caffeine and polyphenols, are powerful inhibitors of Iron absorption (by up to 66%), and should not be consumed within an hour after taking oral Iron. Even moderate amounts of coffee and tea decrease the absorption of Iron from both supplements and dietary sources. And yes, that includes green tea. The catechins in green tea interfere with Iron absorption, too. Skip the Iron with breakfast if you rely on a caffeine fix to get going in the morning.

Timing supplements around certain activities like exercise, blood work and vaccinations is something to be mindful of. 

• Exercise: Supplements like creatine and protein may have greater benefit when used after exercise, supporting muscle recovery and adaptation. 

• Blood work: Biotin, or Vitamin B7, can interfere with a laboratory process used for identifying certain hormones. This can lead to false results for thyroid function tests (TSH, free T4, free T3), parathyroid hormone (PTH) and others. This interference is dose-dependent but starts at doses as low as 10 mg/day, which are common in over-the-counter supplements (including prenatals). Wait until after you blood work to take biotin-containing vitamins. 

• Vaccines: No need to separate the timing of dietary supplement dosing from vaccine administration, there are no known interactions.