Iron and Selenium: Yes, You Can Take Them Together

Yes, you can take iron and selenium together, from the same hand and with the same glass of water. No gap is needed between the two. Full stop. It looks different with a third trace element that many people ask about in the same breath: zinc. That one belongs apart from iron.

Behind the question there is usually an intake plan that is already full: an iron supplement for the tired days, selenium for the thyroid, maybe zinc on top, and the tablet from the doctor every morning anyway. Where does it all go? Morning, noon, evening? That can be solved, with gaps that fit into a full working day with shift changes, canteen lunches and two coffee breaks.

Why iron and selenium don’t fight over the same door

Minerals get in each other’s way when they use the same transport routes in the small intestine. Iron and zinc apparently do that in part. A review on iron and trace elements links the influence of zinc on iron status to competition for metal transporters. Selenium crosses the gut wall differently. According to the 2023 EFSA opinion, the organic form selenomethionine reaches the blood via methionine transporters, selenite by passive diffusion, and selenate via a carrier of its own.

That speaks against a race. It isn’t proof, though: we haven’t found a human trial that tests just these two against each other. The review names manganese and zinc above all as clear interaction partners of iron. Selenium appears in its title, but the abstract offers no finding of its own on it.

In the Thyroid Complex, the selenium comes as L-selenomethionine, exactly the organic form that reaches the blood via the methionine transporters: 55 µg in every capsule, plus 155 µg of iodine from kelp and 185 mg of thyme extract.

Zinc next to iron: here a gap is worth it

A trial from Cambodia shows what this looks like. Mostly anaemic women received, for twelve weeks, daily either 60 milligrams of iron, a multi-nutrient supplement without iron containing among other things 15 milligrams of zinc, 65 micrograms of selenium and 2 milligrams of copper, both together, or a placebo. Blood was measured at the start and after twelve weeks. With iron in the multi-nutrient supplement, blood zinc rose less: 11.6 instead of 12.3 micromoles per litre. The authors suspect the iron interferes with the absorption or metabolism of zinc. An effect you can avoid with the clock.

The abstract reports the interaction for zinc. It says nothing about selenium. In practice that means: iron and zinc go several hours apart, for example iron at lunch and zinc after dinner. Selenium can sit next to either.

What the two trace elements contribute in the body

Iron contributes to normal formation of red blood cells and haemoglobin. Iron contributes to normal oxygen transport in the body and to the reduction of tiredness and fatigue. On top of that come a contribution to the normal function of the immune system and to normal cognitive function.

Selenium contributes to normal thyroid function. Selenium contributes to the normal function of the immune system. Selenium contributes to the maintenance of normal hair, selenium contributes to the maintenance of normal nails, and selenium contributes to the protection of cells from oxidative stress. According to the DGE, the enzymes that regulate the balance of thyroid hormones also depend on selenium.

The two work on different parts of the same gearbox. In the immune system they overlap without replacing each other. Selenium doesn’t replace iron. Nor the other way round.

How to spread iron, selenium and zinc across your day

Lunch: iron and selenium. The iron goes with a meal that includes vitamin C, for example peppers in a salad or an orange afterwards. Vitamin C increases iron absorption. The DGE also names it as an aid to utilisation. Our Iron Bisglycinate + Vitamin C brings the vitamin C source with it: 20 mg of iron as bisglycinate and 40 mg of natural vitamin C from rosehip in one tablet. Polyphenols in coffee and above all in black tea slow absorption down, as do phytates in wholegrain products and pulses, exactly the side dishes that don’t suit an iron capsule. According to EFSA, calcium and zinc also inhibit the absorption of non-haem iron, the kind found in plants. A milky coffee with the iron capsule? Skip it.

A specialist article in Pharmazeutische Zeitung advises taking iron supplements about half an hour before eating, or with meals if tolerance is poor. That fits EFSA: digestive complaints occur mainly with high iron doses on an empty stomach. If you react sensitively, take the iron with food.

Selenium: whenever. The DGE’s information on selenium doesn’t prescribe a time of day. Put the capsule with the iron tablet or with another meal, whichever you forget less often. The Thyroid Complex supplies the selenium in one capsule with 55 µg.

Evening: zinc. After dinner, with several hours of space from the lunchtime iron. An example day: 12:30 lunch with iron, vitamin C and selenium, 19:30 dinner, then the zinc.

L-thyroxine, iron and selenium: if you take thyroid tablets, you plan differently

Here the iron is the sticking point. Iron forms a complex with levothyroxine, and the effect of the thyroid hormone can weaken. Pharmazeutische Zeitung backs this with a study on iron sulphate and recommends at least two, better four hours between thyroid hormone and polyvalent cations. In practice: the tablet first thing in the morning on an empty stomach, the iron at midday or in the evening.

Your plan belongs in the hands of your doctor or pharmacist here. Thyroid values are finely tuned. A shifted timing may only show up in your next lab result. That also applies if you want to add selenium or iodine.

How much selenium and iron per day make sense

Selenium. The DGE gives an estimated value of 70 micrograms a day for men and 60 for women, and 75 for breastfeeding women. European soils tend to be low in selenium, so meat, eggs and fish are the more reliable sources. Vegetarians and vegans are on average less well supplied. Brazil nuts contain around 103 micrograms per 100 grams. The DGE doesn’t recommend more than two a day, because of the nuts’ natural radiation content.

At the upper end, the total from food and all supplements counts. Anyone who takes a great deal over the long term through supplements risks, according to the DGE, selenosis, with tiredness, hair loss, disturbed nail formation and garlic-like breath. According to the DGE, most supplements stay at 200 micrograms or less.

Iron. The DGE gives 16 milligrams a day for women before menopause, 14 after, 11 for men and 27 for pregnant women. EFSA did not set an upper limit in 2024, but names 40 milligrams a day from food and supplements together as a safe level for adults. Plant-based iron is used less well. According to the DGE, vegetarians and vegans should therefore make sure they get enough.

You don’t take iron on suspicion. Ferritin and a blood count at the doctor’s show whether your store is empty. Selenium is similar, except that a deficiency from low intake is rare in Europe, according to the DGE.

Multi-nutrient supplements with iron, zinc and selenium: what the label says

Anyone searching for iron-zinc-selenium tablets, some with iodine too, will find a few. The problem sits in the phrase “everything in one tablet”. In the Cambodian trial, the iron content of the multi-nutrient supplement alone dampened the rise in zinc. A product that packs both in high amounts together therefore takes away exactly the separation that iron and zinc need.

Look at four lines. First, the amount of iron per daily dose, not per capsule. Second, the amount of zinc, because small amounts collide less with iron than high ones. Third, the selenium in micrograms: the number, not the word “selenium” on the front. Fourth, the form: selenomethionine, selenite and selenate are different compounds. If the product contains iodine and you take thyroid medication, check with your doctor’s practice before buying. With us, the building blocks stay separate, so you put iron and zinc on different meals yourself.

Matching Products from Scheunengut

Scheunengut has been around since 2012, with no investors behind us and a focus on pure raw-material quality. We have raw materials and every finished batch tested by an independent lab. We deliberately don’t carry a combination of iron, zinc and selenium in one tablet: for iron and zinc it would be the wrong solution. That is why the building blocks come separately.

Iron Bisglycinate + Vitamin C. One tablet contains 20 mg of iron (143% of the nutrient reference value) as bisglycinate, an organically bound chelate form in which the iron is attached to the amino acid glycine. On top come 40 mg of natural vitamin C from rosehip (50%). Highly bioavailable and well tolerated, without the typical stomach pressure, vegan, made in Germany, lab-tested batch by batch, for €0.09 a day. Iron contributes to the reduction of tiredness and fatigue and to normal formation of red blood cells and haemoglobin. Vitamin C increases iron absorption. This is your building block for lunch.

Thyroid Complex. In one capsule the complex delivers 55 µg of selenium as L-selenomethionine (100% of the nutrient reference value) and 155 µg of iodine from kelp (100%), plus 185 mg of thyme extract. The kelp is cultivated in Japan, we source the thyme from our farmer in Italy, and no chemical solvents are used. For €0.12 a day. Selenium contributes to normal thyroid function and to the normal function of the immune system. Iodine contributes to the normal production of thyroid hormones. If you take thyroid medication, clear the complex with your doctor’s practice first.

Zinc. We don’t carry a standalone zinc supplement. Zinc is found in our complexes, in the Fadogia Strength Complex with 5 mg of zinc per daily dose and in PMS Intenso with 10 mg. For the evening, with a gap from the lunchtime iron. Zinc contributes to the normal function of the immune system.

Frequently Asked Questions (FAQ)

Can you take iron and selenium together?

Yes. You can swallow both in the same minute. According to the EFSA opinion, selenium uses different absorption routes from the metal transporters that iron and zinc compete for, and no required gap between the two is known. We have, however, not found a trial that tests just iron and selenium against each other.

Can you take zinc, selenium and iron together?

Selenium and iron, yes. Zinc is better not taken at the same time as iron. With 60 milligrams of iron in a multi-nutrient supplement, blood zinc rose less. Put iron at midday and zinc in the evening. Selenium can go with either.

When is the best time to take iron and selenium?

Iron with lunch, ideally with a source of vitamin C and without coffee or black tea. Put selenium with it or with another meal; the DGE doesn’t prescribe a time of day for it. With us, the Iron Bisglycinate + Vitamin C (20 mg of iron per tablet) and the Thyroid Complex (55 µg of selenium per capsule) fit in. If you take L-thyroxine, keep at least two, better four hours between it and the iron.

What should you make of iron-zinc-selenium tablets?

They save capsules but force a compromise, because iron and zinc don’t belong in the same intake. Check the amount of iron per daily dose and how much zinc and selenium (in micrograms) is really in there. If the tablet also contains iodine, discuss it with your doctor’s practice if you have thyroid problems.

Do iron and selenium go with L-thyroxine?

Iron forms a complex with levothyroxine and can reduce its absorption. A specialist article in Pharmazeutische Zeitung recommends at least two, better four hours between them. Never change your intake plan on your own; clear it with your doctor or pharmacist.

How much selenium and iron per day is enough?

For selenium, the DGE gives 70 micrograms for men and 60 for women, add up food and all supplements and follow the label. For iron, the reference value is between 11 and 16 milligrams; pregnant women need 27. You don’t take iron on suspicion, but after a blood count.