{"id":54771,"date":"2022-10-21T09:30:38","date_gmt":"2022-10-21T13:30:38","guid":{"rendered":"https:\/\/www.singlecare.com\/blog\/?p=54771"},"modified":"2026-07-10T18:55:11","modified_gmt":"2026-07-10T22:55:11","slug":"what-vitamins-should-not-be-taken-together","status":"publish","type":"post","link":"https:\/\/www.singlecare.com\/blog\/what-vitamins-should-not-be-taken-together\/","title":{"rendered":"What vitamins should not be taken together?"},"content":{"rendered":"

From collagen powder and probiotics to prenatal vitamins and St. John\u2019s wort<\/a>, the sale of vitamin, mineral, and herbal supplements is skyrocketing. In fact, according to data from the most recent National Health and Nutrition Examination Survey, an estimated 57% of Americans older than 20 take at least one dietary supplement. Multivitamins, vitamin D, and omega-3 fatty acids are the most popular.<\/p>\n

Maybe you take a daily multivitamin<\/a> to enhance your overall health and wellness. Or perhaps you rely on supplements to fill in essential nutrient gaps. Either way, it\u2019s important to be aware of possible interactions. Vitamins are organic compounds that are essential in small amounts for normal metabolism. Taking certain vitamins together can affect their absorption in the body\u2014sometimes blocking and other times improving bioavailability.<\/p>\n

Additionally, some vitamins can interfere with the efficacy of other medications and even exacerbate side effects. Although measuring serum levels of several essential vitamins is widely available, testing for deficiencies is usually unnecessary. Here\u2019s what you need to know about using vitamin supplements wisely.<\/p>\n

What vitamins should not be taken together?<\/h2>\n

It is very important to read the label and the suggested supplementation protocol for each supplement you are taking, advises Jenna Litt, RD, CDN<\/a>, a registered dietitian at Northwell Health\u2019s Lenox Hill Hospital<\/a> in New York. \u201cFor example, some supplements may need to be taken with food, some may be administered daily, multiple times a day, or even weekly,\u201d she says. \u201cIf you are not sure about dosage, contact your healthcare provider to ensure you are taking proper dosages.\u201d\u00a0<\/p>\n

It\u2019s also important to know which vitamins should not be taken together<\/i>. Here are supplements that don\u2019t go together\u2014or shouldn\u2019t be taken with food.<\/p>\n

Magnesium and calcium<\/h3>\n

Why not together: <\/b>Although these two minerals work together, they must be in balance to be effective. While magnesium<\/a> does help with calcium<\/a> absorption, too much calcium (essential for bone health) can actually have the opposite effect and prevent magnesium from being absorbed. Research<\/a> indicates that a calcium-to-magnesium ratio above 2:1 is linked to an increased risk of metabolic, inflammatory, and cardiovascular disorders.<\/p>\n

Recommendations:<\/b> To be sure you\u2019re getting the correct ratio, consult with your provider for guidance on combining calcium and magnesium mineral supplements.<\/p>\n

Iron and calcium<\/h3>\n

Why not together?<\/b> Research<\/a> shows that nearly one in three American adults have low iron levels. Your healthcare provider may recommend taking iron supplements if you\u2019re not getting enough iron through your diet. But if you also supplement with calcium, your best bet is spacing out the doses. According to research<\/a>, calcium can inhibit iron absorption, meaning it won\u2019t be as effective.<\/p>\n

Recommendations: <\/b>For best results, take calcium (including milk products) and iron one to two hours<\/a> apart.\u00a0<\/p>\n

Iron and green tea<\/h3>\n

Why not together:<\/b> It\u2019s not a good idea to take your iron supplement<\/a> (or eat iron-rich foods) at the same time as green tea. That\u2019s because the main component in green tea, epigallocatechin gallate (EGCG), binds with iron<\/a> and reduces its absorption. A case study<\/a> linked drinking large amounts of green tea with the development of iron deficiency anemia.<\/p>\n

Recommendations:<\/b> Green tea has health benefits, though, so feel free to drink it\u2014just do so in moderation and wait two hours after taking an iron supplement.<\/p>\n

Vitamin C and B12<\/h3>\n

Why not together: <\/b>It\u2019s not advised to take vitamin C<\/a> and vitamin B12<\/a> at the same time, says Litt. That\u2019s because high doses of vitamin C can reduce the amount of vitamin B12 that\u2019s absorbed and metabolized<\/a> by the body, she says.<\/p>\n

Recommendations:<\/b> Be sure to take vitamin C at least two hours<\/a> after vitamin B12 to avoid a B12 deficiency.<\/p>\n

RELATED: Can you take too much B12?<\/a><\/strong><\/p>\n

Vitamin C and copper<\/h3>\n

Why not together? <\/b>Most people don\u2019t need to take a copper supplement, but individuals<\/a> with celiac disease, Menkes disease (a rare genetic disorder), and those taking high amounts of zinc may. But if you\u2019re taking copper and vitamin C, the combination can be dangerous. According to research<\/a>, mixing the two supplements can cause oxidative stress and kidney damage.<\/p>\n

Recommendations: <\/b>Play it safe by spacing out your copper and vitamin C supplements by two to three hours.\u00a0<\/p>\n

Fat-soluble and water-soluble vitamins<\/h3>\n

Some combinations should be avoided, even if they aren\u2019t inherently problematic. For example, although it\u2019s safe to take vitamin D with vitamin B12, it\u2019s not advisable, says Virgilio Sanchez, MD<\/a>, a board-certified family physician at Conviva Care Center in Miami, Florida. That\u2019s because vitamin D is a fat-soluble vitamin that\u2019s absorbed better with food, while B12 is a water-soluble vitamin that should be taken on an empty stomach, says Dr. Sanchez. The same goes for vitamin C and vitamin D\u2014they should be taken at different times.<\/p>\n

Similarly, water-soluble vitamins (which are not stored in the body), like vitamin C, B vitamins\u2014including thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), biotin (B7), folate\/folic acid (B9), and cobalamin (B12)\u2014require water to be absorbed and used by the body, says Dr. Ormond. It\u2019s best to take them without food with a glass of water.<\/p>\n\n\n\n\n\n\n\n\n\n
Vitamin interactions chart <\/span><\/strong><\/th>\n<\/tr>\n<\/thead>\n
Vitamin<\/b><\/td>\nInteractions<\/b><\/td>\nHow to improve absorption and reduce side effects<\/b><\/td>\n<\/tr>\n
Magnesium<\/td>\nToo much calcium<\/td>\n\n
    \n
  • Vitamin D3<\/li>\n
  • Take in the evening for relaxation<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n
Iron<\/td>\nGreen tea<\/td>\n\n
    \n
  • Vitamin C<\/li>\n
  • Take with food to avoid stomach upset<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n
Vitamin C<\/td>\nVitamin B12<\/td>\n\n
    \n
  • Can be taken without food<\/li>\n<\/ul>\n<\/td>\n<\/tr>\n
Fat-soluble vitamins (vitamins A, D, E, K)<\/td>\nWater-soluble vitamins (vitamin C and B vitamins)<\/td>\n\n