What vitamins shouldn’t be taken together really depends on the type of supplement.
Some vitamins work best with or after a meal (especially ones containing fat), while others should be taken on an empty stomach.
Certain individual nutrient supplements (such as mineral supplements) shouldn’t be taken together often because they affect the absorption of one another such as Iron and Calcium.
Health experts agree that the best way to get all the essential nutrients you need lies in healthy eating. Consuming a wide variety of nutrient-dense foods will deliver the vitamins and minerals your body needs to thrive. In fact, every system in your body depends on these nutrients to function properly and maintain good health. But for a variety of reasons, many people fall short when it comes to consistently eating a nutritious, balanced diet. So, they turn to dietary supplements to make up for any shortfall.
In fact, supplementing can help boost your intake of a specific vitamin or mineral.
However, if you take more than one supplement, you might wonder, “What vitamins shouldn’t be taken together?” On the flip side, you might also wonder, “What vitamins can I take together?”
Vitamins play a vital role in keeping us healthy, but should they be taken at the same time? Keep reading to learn what vitamins shouldn’t be taken together —and which ones pair well together.
Can You Take All Your Vitamins At The Same Time?
Vitamins are classified into two main categories: water-soluble and fat-soluble vitamins. As a quick refresher, your body needs 13 essential vitamins for normal cell function, growth, development, and overall optimal health. 
The body stores fat-soluble vitamins—including Vitamins A, D, E, and K—in fatty tissue. Because of this, fat soluble vitamins are absorbed more easily in the presence of dietary fat, so avoid taking them on an empty stomach. Instead, take a fat soluble vitamin with a meal or snack, making sure it includes a healthy fat (such as avocado, eggs, fatty fish, olive oil, nuts, or seeds).
As the name indicates, a water soluble vitamin are found in the water-based tissues of the body. The body does not store water-soluble vitamins—including the B Vitamin family and Vitamin C—and any “leftovers” leave the body through the urine.  The B vitamins include the following:
Vitamin B1 (Thiamin)
Vitamin B2 (Riboflavin)
Vitamin B3 (Niacin)
Vitamin B5 (Pantothenic Acid)
Vitamin B7 (Biotin)
Vitamin B9 (Folate/Folic Acid)
Vitamin B12 (Cobalamin)
What Vitamins Should You Avoid Taking Together?
Certain supplements seem to work against each other when paired up. What vitamins shouldn’t be taken together?
Iron and Calcium
If you take an Iron supplement and Calcium supplement at the same time, this will result in decreased Calcium absorption in the intestine. Why? Because as these two minerals hey both compete with one another for absorption in the body. In fact, it’s probably best if you take a Calcium supplement at a different time from your multivitamin (that may contain Iron) or an Iron-rich meal. Ditto if you’re taking an Iron supplement—avoid taking it with Calcium-rich foods (like milk or leafy greens).
High doses of Iron and Zinc
If you take a high dose Iron supplement along with a Zinc supplement on an empty stomach, this may block Zinc absorption.  It is never recommended to take an iron supplement on an empty stomach.
High doses of Calcium, Zinc or Magnesium
As noted above with the Iron and Calcium combo above, Calcium will compete for absorption with other minerals. Since Calcium can affect how your body absorbs Iron, it can also affect the absorption of Zinc and Magnesium, too.  While it’s OK to take them together in a multivitamin (which typically contains smaller doses of these minerals), it’s best to space out these supplements if you’re taking them individually.
Copper and Zinc
If you’re taking a Zinc supplement, don’t take it at the same time as Copper, Iron, or Phosphorus supplements. Instead, space them out a couple hours apart.  In general, large amounts of minerals taken at the same time as other minerals will reduce absorption of each other.
What Vitamins Should You Consider Taking Together And Why?
Often recognized as a group, the B vitamins often work together in the body and are often found together in the same food. The B vitamins perform unique, important functions, like converting food into energy, maintaining healthy cells and tissues in the body, and helping to form new blood cells. As a supplement, these are vitamins that can be taken together, either as an individual nutrient (such as Vitamin B12) or combined into a B Complex supplement. †
Vitamin C and Zinc
According to recent research, “The prevalence of inadequate nutrient intakes that support the immune system (Vitamin A, C, D, E) remain substantial and some are higher (Vitamins C, D, and Zinc) than previously reported.”  That’s why you might commonly see Vitamin C and Zinc together in immune supplements. †
Iron and Vitamin C
Vitamins that can be taken together also include Iron and Vitamin C, since Vitamin C strongly increases the absorption of non-heme Iron (Iron from plant-based sources). 
Best Ways To Take Different Vitamins
Take water-soluble vitamins, like B Vitamins and Vitamin C, with a glass of water and a meal or snack The when is up to you. For some people, this might work best first thing in the morning while eating breakfast or at lunch.
Since B vitamins help you get the cellular energy you need, it might be best to take Vitamin B12 or other Vitamin B supplements in the morning so it doesn’t impact your sleep. †
Keep in mind that some vitamin supplements and mineral supplements may interfere with certain medications, including antibiotics, blood thinners, and blood pressure medications. Taking them together may affect nutrient absorption and may cause side effects and other issues. Therefore, always talk with your healthcare provider before taking any supplements—especially if you regularly take medication.
Finally, take your dietary supplements in the recommended daily doses and pay attention to what you eat. Taking an excessive amount of a supplement may result in a large dose of a specific nutrient, which may be harmful to your health.
What About Multivitamins?
Many health experts say it’s often less about what time you take supplements and more about whether you’re taking them with a meal and/or with water. For most supplements—including your daily multivitamin—you should take them with your largest meal of the day, which is probably lunch or dinner. Ideally, the meal should contain some healthy fat (think avocado, eggs, fatty fish, or nuts) to allow optimal absorption of the fat-soluble vitamins. The most important point to remember? Take your daily multivitamin supplement with food and drink some water in order to aid digestion and absorption.
And what about a prenatal vitamin? Since a prenatal supplement is also a multivitamin, take it with a meal. Why? Because the vitamins and minerals (especially those fat soluble vitamins like Vitamins A, D, E, and K and Omega-3s like DHA) absorb best with a meal that contains some fat. Since it helps to take your vitamins at the same time every day to establish this healthy habit, take them at breakfast, lunch, or dinner--whatever works best for you.
How Can Supplements Help Me Support My Health?
Supplements can support your nutritional needs, from A to Zinc. While they don’t replace healthy eating, they do help fill in any nutrient gaps to support your health and well-being. To ensure you’re choosing the right supplement to meet your individual needs and health goals, first talk to your doctor. Then, make sure you choose a high-quality supplement from a trusted brand like Nature Made®. Grounded in decades of research, we deliver high-quality, science-backed products—and we’ve been an industry leader since 1971.
The body stores fat-soluble vitamins—including Vitamins A, D, E, and K—and they’re absorbed more easily in the presence of dietary fat, so avoid taking them on an empty stomach. Take them with a meal or snack that includes a healthy fat. Water-soluble vitamins—including the B Vitamin family and Vitamin C—are found in the water-based tissues of the body and should be taken with water and food. What vitamins shouldn’t be taken together? Mineral supplements—often because they affect the absorption of one another. Other individual nutrient supplements (like B Vitamins) pair well together because they enhance how one another works in the body. Your best bet is to follow the directions on the supplement package. And talk to your doctor about your supplement routine, asking about any questions or concerns.
Continue to check back on the Nature Made blog for the latest science-backed articles to help you take ownership of your health.
† These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.
Lisa Beach is a seasoned journalist whose work has been published in The New York Times, Good Housekeeping, Eating Well, Parents, AARP’s Disrupt Aging, Optimum Wellness, and dozens more. She also writes for a variety of health/wellness-focused brands. Check out her writer’s website at www.LisaBeachWrites.com.
Lynn is a Registered Dietitian (R.D.) and is a member of the Medical and Scientific Communications team at Pharmavite. She has over 20 years of experience in integrative and functional nutrition and has given lectures to health professionals and consumers on nutrition, dietary supplements and related health issues. Lynn frequently conducts employee trainings on various nutrition topics in addition to educating retail partners on vitamins, minerals and supplements. Lynn has previous clinical dietitian expertise in both acute and long-term care, as well as nutrition counseling for weight management, diabetes, and sports nutrition. Lynn earned a bachelor’s of science in Nutrition with a minor in Kinesiology/Exercise Science from The Pennsylvania State University. She earned a M.S. degree in Human Nutrition from Marywood University in Scranton, Pennsylvania. Lynn is an active member of the Academy of Nutrition and Dietetics, Sports Cardiovascular and Wellness Nutritionists, Dietitians in Functional Medicine, and holds a certification in Integrative and Functional Nutrition through the Academy of Nutrition and Dietetics.