Anyone with a few jars on the kitchen counter ends up asking the same question sooner or later: can all of this go in at once, or should I space it out? The honest answer is that it usually just can. There are only a handful of combinations where it truly matters, and they are easy to remember. Below are the rules that explain most of it, then a short answer for each combination people ask about, and at the end a daily schedule you can simply copy.
Three rules that explain almost everything
Calcium and iron get in each other’s way. They use the same route into the body in the gut, and calcium wins. Take iron and calcium at the same moment and you absorb less iron. Two hours apart is enough.
Vitamin C actually helps iron. This is one of the few combinations the science is so clear on that it has been approved as an official claim: vitamin C increases iron absorption. Iron with a glass of orange juice or alongside a vitamin C capsule is not a coincidence, it is the point. Coffee and tea do the opposite; they slow iron absorption, so leave an hour between them.
Fat-soluble vitamins need fat. Vitamin D and vitamin K dissolve in fat, not in water. With a meal that contains some fat, a slice of bread with cheese or an egg is already enough, you absorb them better than on an empty stomach with a sip of water.
Everything else, magnesium, zinc, B vitamins, omega 3 and vitamin D among themselves, can go together without any issue. Nothing to space out there.
Vitamin D and K2
This is the combination people search for most, and the reason is that both have something to do with calcium. Vitamin D contributes to normal absorption of calcium. Vitamin K contributes to the maintenance of normal bones, and calcium itself is needed for that. That is why you so often see them in a single capsule. They can go together, with the same meal, and both preferably with a little fat. If you would rather not buy them separately, this line-up sits in Bone Aid by Together: calcium, magnesium, vitamin D and vitamin K2 in one capsule. Prefer them apart? Vitamin D3 and vitamin K2 are on the shelf separately.
Magnesium and vitamin D
Fine together. There is no known reason to space them, which is also why they sit side by side in Bone Aid. Magnesium contributes to the reduction of tiredness and fatigue and to normal functioning of the nervous system; vitamin D to the maintenance of normal muscle function and to the normal function of the immune system. Many people take magnesium in the evening, but that is a habit, not a rule. It is fine at breakfast too, next to your vitamin D.
Vitamin B12 and magnesium, or B12 and vitamin D
Both fine together as well. B12 is water-soluble and is not bothered by magnesium or by vitamin D. Vitamin B12 contributes to normal energy-yielding metabolism and to the reduction of tiredness and fatigue, the same claim that applies to magnesium, so people who feel tired often combine them. A B complex with magnesium at breakfast is a calm, logical start.
Calcium and magnesium
Can go together. You sometimes read that they hinder each other, but at the amounts in an ordinary supplement there is no good evidence for that. There is a reason they sit together in most bone formulas, including Bone Aid. What does matter: calcium away from iron, see the first rule.
Zinc and magnesium, zinc and iron
Zinc and magnesium can simply go together. Zinc and iron are better not taken at the same moment if you take both in a high dose, because those two also partly share the same route. If you only take one of the two as a separate supplement, it does not come into play.
Iron and vitamin C
The happiest combination on this whole list. Iron contributes to normal oxygen transport in the body and to the reduction of tiredness and fatigue, and vitamin C increases iron absorption. Take them together, away from coffee and away from calcium. With us: Super Iron by Vegums next to vitamin C by Together.
Omega 3 and magnesium
Fine together. Omega 3 is a fat, so you take it with a meal anyway, and magnesium can sit right next to it. At 250 mg of EPA and DHA a day, the approved claim applies that they contribute to the normal function of the heart.
At a glance
| combination | together? | note |
|---|---|---|
| vitamin D and K2 | yes | with a meal containing fat |
| magnesium and vitamin D | yes | none |
| B12 and magnesium, B12 and vitamin D | yes | none |
| calcium and magnesium | yes | none |
| zinc and magnesium | yes | none |
| omega 3 and magnesium | yes | omega 3 with a meal |
| iron and vitamin C | yes, gladly | vitamin C increases iron absorption |
| calcium and iron | space out | two hours apart |
| zinc and iron | space out at high doses | otherwise no issue |
| iron and coffee or tea | space out | an hour apart |
A daily schedule that works
At breakfast: vitamin D, K2, calcium and magnesium, or Bone Aid if you want them in one capsule, plus your B vitamins. Breakfast supplies the fat for D and K, and the B vitamins are in straight away. Omega 3 can go here too, or with dinner.
Mid-morning or in the afternoon, at least two hours after the calcium and an hour after your coffee: iron, with vitamin C. That is the only moment you genuinely need to plan.
Do you use CBD oil? You can take it at the same moment as your supplements; there is no reason to space it. If you take medication, that is a different matter: consult your doctor or pharmacist, and read our article on CBD and medicines.
Frequently asked questions about taking supplements together
Which vitamins are better not taken together?
It is really not about vitamins but about minerals: calcium and iron, and at high doses zinc and iron. Those use the same route in the gut. All common vitamins can go together.
Can you take vitamin D and B12 together?
Yes. They have nothing to do with each other in absorption. Vitamin D is best taken with a meal containing some fat; for B12 it makes no difference.
Can you take magnesium and B12 together?
Yes, that is fine. They share the same approved claim about the reduction of tiredness and fatigue and are therefore often taken together.
Can you take calcium and magnesium together?
Yes. At supplement amounts there is no good evidence that they hinder each other. They sit together in Bone Aid.
Can you take zinc and magnesium together?
Yes. Zinc and magnesium do not affect each other. Only watch zinc in combination with a high dose of iron.
Can you take omega 3 and magnesium together?
Yes. Omega 3 is taken with a meal because it is a fat, and magnesium can sit right next to it.
Another question?
If you are unsure about a combination that is not listed here, ask through customer service. For medication, your doctor or pharmacist is the right person; we do not give medical advice.
