Iron Tablets and Tea or Coffee: How Long to Wait, and What Else Matters

Britain runs on tea, and the first cup usually arrives with breakfast, which is exactly when many of us swallow our supplements. If you have been told to "avoid tea" with iron tablets and wondered whether that means ten minutes or the whole day, you are not alone. This guide sets out what the research found, how long to wait, and how to fit iron around milk, vitamin C, other supplements and medicines without overhauling your day.

Iron tablets and tea: the short answer

If you only remember three things, make it these:

1. Before beats after. In one study, coffee drunk an hour before a meal did not reduce the iron absorbed from that meal. Coffee drunk an hour after it cut absorption just as much as coffee drunk with the meal.
2. After your iron, wait about two hours. That is the gap NHS guidance for ferrous sulfate, a common iron tablet, gives for tea, coffee, eggs and dairy. If two hours is not realistic, one hour still helps: a UK study found that waiting an hour after an iron-containing meal halved the effect of tea.
3. Take it with water or orange juice. Vitamin C increases iron absorption. Tea, coffee, cocoa, herbal teas and milk all work against it.

The rest of this guide explains why, and how to make it work around your day.

Why tea and coffee get in the way

There are two kinds of iron in food. Haem iron comes from meat and fish. Non-haem iron comes from plant foods, fortified foods and supplements, and it is the kind most affected by what you eat and drink with it. Iron supplements, including iron bisglycinate, provide non-haem iron.

Tea and coffee are rich in polyphenols, natural plant compounds such as the tannins in black tea and the chlorogenic acid in coffee. In the gut, these compounds hold on to non-haem iron and make it harder for your body to absorb.

The effect is not small. In a classic absorption study, a cup of coffee with a meal cut the iron absorbed from it by 39%, and a cup of tea cut it by 64%. Stronger coffee had a bigger effect. In another study, black tea reduced the iron absorbed from a bread meal by 79% to 94%.

It is the polyphenols, not the caffeine

Switching drinks does not always help. In the same bread-meal study, herbal teas, which contain no caffeine, reduced iron absorption too: peppermint by 84% and camomile by 47%. Cocoa cut it by 71%. Adding milk to tea or coffee made little or no difference.

Does this apply to tablets as well as meals?

Most of these studies measured iron from meals rather than from tablets. The same principle seems to hold for supplements, though: the coffee study also found that coffee reduced the absorption of iron compounds when no food was eaten at all. Treat the percentages as a guide to the size of the effect rather than a precise prediction for any one tablet.

How long to wait after taking iron before tea or coffee

Advice online ranges from "an hour" to "four hours". Here is what the evidence and NHS guidance actually say.

• Tea or coffee first, iron later. In the coffee study, coffee drunk an hour before a meal did not reduce iron absorption at all.
• Iron first, then a one-hour wait. A UK trial gave 12 healthy women an iron-containing porridge meal on three occasions: once with water, once with tea and once with tea an hour later. Tea with the meal cut absorption by about 37% compared with water. Waiting an hour roughly halved that, to about 18%.
• Iron first, then a two-hour wait. NHS guidance for ferrous sulfate says to leave a two-hour gap before having tea, coffee, eggs or dairy.

The two studies do not agree perfectly. The coffee study found that coffee an hour after a meal still reduced absorption as much as coffee with the meal, while the UK tea study found an hour's wait helped. They used different drinks, meals and methods, and the UK study was small. The answer that fits all of the evidence: have your hot drink before your iron where you can, and after your iron aim for two hours, with one hour as a fallback.

With a meal or on an empty stomach?

Iron is absorbed best on an empty stomach. That is why NHS guidance for ferrous sulfate, a common prescribed iron tablet, suggests taking it 30 minutes before eating or 2 hours after. Iron can upset some people's stomachs, though, and the same guidance says you can take it with or after food if that happens. The NHS guide to iron deficiency anaemia goes further and suggests taking tablets with or soon after food to reduce the chance of side effects.

For an everyday supplement, the best plan is the one you will stick to. Vita London's Gentle Iron + Energy Support Tablets are taken once a day, preferably at mealtime. Each tablet provides 14mg of iron as iron bisglycinate (iron bound to glycine, an amino acid), with vitamin C, vitamin B6, vitamin B12 and folic acid. Take it as directed, and choose the meal that is easiest to keep free of tea, coffee and dairy. For many tea drinkers, that is lunch.

Vitamin C helps; milk and calcium don't

Vitamin C: the helpful partner

Vitamin C increases iron absorption. That is an authorised health claim in Great Britain, and the NHS notes that a doctor or pharmacist may suggest taking iron tablets with orange juice or a vitamin C supplement. The British Dietetic Association also suggests eating vitamin C-rich foods, such as salad or a glass of juice, with meals.

Gentle Iron already contains 60mg of vitamin C in each tablet, so a glass of water is fine. A small glass of orange juice, or vitamin C-rich foods such as peppers, tomatoes, broccoli, kiwi or citrus fruit at the same meal, is an easy extra.

Milk, yoghurt and calcium supplements

Calcium is the other big one. In a study of 126 people, 165mg of calcium from milk or cheese eaten with a meal reduced iron absorption by 50% to 60%. The NHS gives the same two-hour gap for dairy as it does for tea and coffee. A milky latte or a cup of milky tea gives you both problems at once.

There is some reassurance. A UK study found that calcium supplements taken with meals sharply cut the iron absorbed from those meals, yet over six months they did not lower iron stores in adults who already had enough iron. The effect is clearest meal by meal, so if you want to get the most from an iron supplement, keeping it apart from dairy and calcium supplements is a simple, worthwhile step.

Fitting iron around other supplements and medicines

If you take several supplements, the simplest rule is to keep iron apart from other minerals. NHS guidance on iron tablets asks you to tell a pharmacist if you take supplements containing iron, calcium, magnesium or zinc, and notes that ferrous sulfate can stop zinc working as well as it should.

For example, if you take Gentle Iron alongside Vitamin D3, K2 & Magnesium Glycinate or Vitamin C & Zinc tablets, have the iron at one meal and the others at a different meal.

Vitamin D and vitamin B12

Vitamin D and vitamin B12 are not among the supplements the NHS flags for people taking iron tablets, and Gentle Iron already includes B12 and folic acid. If your vitamin D product also contains calcium or magnesium, treat it like a mineral and take it at a different meal from your iron.

Medicines

Some medicines and iron do not mix well. Tell a pharmacist before taking iron if you take:

• levothyroxine for an underactive thyroid. It is best taken 30 to 60 minutes before your first meal and before any tea or coffee, and the NHS lists calcium and iron supplements among the products that may not mix well with it, so ask your pharmacist or doctor how far apart to take them;
• antibiotics such as doxycycline or ciprofloxacin;
• antacids or other indigestion remedies, or laxatives containing magnesium;
• any other product that contains iron, including some multivitamins.

A tea-friendly day with iron

Here is how this can look in real life. Move the times to suit you; the gaps are what matter.

Option 1: iron with lunch

• Breakfast (7.30am): your usual tea or coffee. If you take levothyroxine, it usually comes first, 30 to 60 minutes before breakfast.
• Lunch (12.30pm): your iron tablet with a glass of water or orange juice. Keep tea, coffee and dairy for another meal.
• Afternoon (2.30pm onwards): your next cuppa, two hours after the iron.
• Evening meal: any calcium, magnesium or zinc supplements you take.

Option 2: iron with your evening meal

• Daytime: tea and coffee as usual, with the last cup at least an hour before dinner.
• Evening meal: your iron tablet with water.
• After dinner: no tea, coffee, hot chocolate or herbal tea for two hours. A bedtime peppermint or camomile tea counts too.

There is little research comparing morning and evening doses of a daily supplement, so choose the time that gives you the cleanest gap from tea, coffee and dairy, and stick with it.

Should you take iron every other day?

You may have seen alternate-day iron discussed online. It comes from research on hepcidin, a hormone that controls how much iron your gut lets in. Large doses of iron raise hepcidin, which can reduce how much of the next dose is absorbed.

In a Swiss trial of women with low iron stores, 60mg doses of iron taken on alternate days were absorbed better than the same doses taken on consecutive days: about 22% of the iron compared with about 16%. That is a prescription-strength dose, more than four times the iron in a Gentle Iron tablet, and the researchers said their findings still needed confirming in people with anaemia.

What that means for you:

• If your GP has prescribed iron, follow their plan. The NHS notes that a doctor may suggest alternate days if you get side effects, but that is their call to make.
• If you take a daily supplement such as Gentle Iron, stick to one tablet a day. The alternate-day research used much larger doses, so it tells us little about a 14mg daily tablet.

Common mistakes, and easy fixes

• Taking iron with your breakfast cuppa. Fix: enjoy the tea first and move your iron to lunch, or to another meal without tea or coffee.
• Swapping to herbal tea and assuming it is fine. Fix: peppermint, camomile and other herbal teas reduce iron absorption too, so give them the same gap.
• Washing it down with a latte. Fix: take iron with water or orange juice and save milky drinks for later.
• Taking every supplement in one handful. Fix: take iron at a different meal from calcium, magnesium and zinc.
• Doubling up on iron. Fix: some multivitamins already contain iron. If yours does, ask a pharmacist before adding a separate iron supplement. The NHS says 17mg or less a day of iron from supplements is unlikely to cause harm.

When to speak to your GP, and what to expect

Low iron intake is common in the UK, particularly for girls and women. In the National Diet and Nutrition Survey (2016 to 2019), 49% of girls aged 11 to 18 and 25% of women aged 19 to 64 had iron intakes below the lower reference nutrient intake, a level that is likely to be too low for most people.

The NHS says adults need:

• 8.7mg of iron a day for men aged 19 and over;
• 14.8mg a day for women aged 19 to 49;
• 8.7mg a day for women aged 50 and over, although women who still have periods after 50 may need the same amount as younger women.

Most people should be able to get all the iron they need from a varied and balanced diet, including foods such as red meat, beans, nuts, dried fruit and fortified breakfast cereals. A supplement can help some people top up their intake, but it is not a way to diagnose or fix a problem on your own.

See your GP if you think you might be low in iron, especially if you notice tiredness and a lack of energy, shortness of breath, a noticeable heartbeat or pale skin. These have many possible causes, and a blood test is the only way to know. Heavy periods and pregnancy are common reasons for low iron; if you are pregnant, your midwife or GP will advise you.

Keep iron supplements out of children's reach. The NHS warns that very high doses of iron can be fatal, particularly for children.

Iron, tea and coffee: your questions answered

Can I drink decaf coffee with iron tablets?

Decaf was not tested in the studies above. Because it still contains the polyphenols found in ordinary coffee, it is sensible to give decaf the same gap.

Do herbal teas affect iron absorption?

Many do. In one study peppermint tea reduced iron absorption by 84% and camomile by 47%, so a caffeine-free tea at bedtime still counts if you take your iron with your evening meal.

Does adding milk to tea make a difference?

Not in a helpful way. Milk made little or no difference to the effect of tea in one study, and the calcium in milk can reduce iron absorption on its own.

Can I take iron and vitamin D at the same time?

Vitamin D is not one of the supplements the NHS flags for people taking iron tablets. If your vitamin D product also contains calcium or magnesium, take it at a different meal.

Is it better to take iron in the morning or at night?

There is little research comparing the two for a daily supplement. Pick the time that gives you the clearest gap from tea, coffee and dairy, and take it at the same time each day.

If you have decided an iron supplement is right for you, Gentle Iron + Energy Support Tablets are a small once-a-day tablet with vitamin C built in. Take one with lunch and a glass of water, and save your next cuppa for mid-afternoon.