Iron Infusion vs Iron Tablets: Which Is Right for You?

Quick answer: For mild iron deficiency, tablets are a reasonable first step: but they only absorb around 10% of their iron and cause nausea or constipation in many people. An iron infusion delivers iron directly into the bloodstream with near-complete absorption, correcting levels in a single session rather than 3-6 months of daily tablets. An infusion is usually the better choice when tablets haven't worked, aren't tolerated, or you need a faster result.

You've been taking iron tablets for months. Maybe your ferritin hasn't budged. Maybe the side effects: the nausea, the constipation, the metallic taste: have made you dread every morning. You're not imagining it, and it's not your fault. Iron tablets genuinely don't work for everyone.

So what's the alternative? An iron infusion delivers iron directly into your bloodstream, bypassing your gut entirely. One session can deliver what would take over five months of daily tablets. But is it the right choice for you?

Here's an honest comparison: what works, what doesn't, and when each option makes sense.

How iron tablets work

Oral iron supplements: ferrous sulphate, ferrous fumarate, or ferrous gluconate: are absorbed through the lining of your small intestine. They're cheap, widely available, and your GP can prescribe them immediately.

The catch: your gut can only absorb around 10% of each dose.

That means if you're taking a 200mg tablet, your body may only absorb 20mg of elemental iron. To replenish depleted stores, you need to do this every single day for 3-6 months: assuming perfect absorption, which rarely happens.

Common reasons absorption drops even further:

• Coffee or tea within an hour of taking them (tannins block absorption)
• Calcium supplements or dairy taken at the same time
• PPIs or antacids (proton pump inhibitors reduce stomach acid, which you need to absorb iron)
• Gut conditions like coeliac disease, Crohn's, or IBD that damage the absorptive lining

And then there are the side effects. Between 30% and 40% of people taking oral iron experience gastrointestinal side effects: constipation, nausea, stomach cramps, dark stools, or diarrhoea. Many stop taking them before their levels have recovered.

How iron infusions work

An IV iron infusion delivers iron directly into your bloodstream through a small drip in your arm. Because it bypasses your digestive system entirely, there are no GI side effects: no nausea, no constipation, no interactions with food or medication.

A single infusion can deliver up to 1,000mg of iron: the equivalent of what 150+ days of daily tablets would deliver, assuming perfect absorption. Your body begins using that iron immediately to produce new red blood cells and replenish ferritin stores.

The infusion itself takes approximately 30 minutes, followed by 30 minutes of monitoring. Most people are in and out within an hour.

At IronOx Clinic, most infusions are led by Dr. Ros Jabar, a GMC-registered doctor with a background in acute medicine and A&E. Other treatments are delivered by an appropriately trained medical professional with full monitoring.

The key differences at a glance

When iron tablets are enough

Iron tablets are a reasonable first step if your deficiency is mild, you tolerate them well, and you don't have an underlying condition affecting absorption. They work for some people: especially if taken consistently on an empty stomach with vitamin C to boost absorption.

Tablets may be appropriate when:

• Your ferritin is mildly low but your haemoglobin is normal
• You don't have coeliac disease, IBD, or other malabsorption conditions
• You can tolerate the GI side effects
• You're not taking PPIs, calcium, or other medications that interfere
• There's no time pressure (no upcoming surgery, no pregnancy concerns)

When an iron infusion makes more sense

For many people, tablets are the starting point: and the infusion is what actually fixes the problem. You might benefit from an infusion if:

• Tablets haven't worked: you've been taking them for months and your ferritin hasn't improved
• You can't tolerate them: nausea, constipation, or stomach cramps have made them unbearable
• You can't absorb oral iron: due to coeliac disease, Crohn's, IBD, or a previous gastric bypass
• You need iron levels raised quickly: before surgery, during pregnancy, or for fertility treatment
• You have heavy periods causing ongoing iron loss that tablets can't keep up with

What about the cost difference?

Iron tablets cost around £5-£15 per month on prescription. A private iron infusion starts from £699 per session. On the surface, tablets look like the obvious choice.

But consider the full picture. If tablets aren't working: and you've spent three, four, five months feeling exhausted while waiting for them to kick in: the real cost isn't financial. It's the months of brain fog, the hair loss, the inability to function, the GP appointments, the repeat blood tests, the supplements you've tried alongside them.

An iron infusion is a single session. Your consultation, specialist assessment, treatment, and follow-up care are all included in the price. For many patients, it's the thing that finally works after months of trying everything else.

How to decide

The right choice depends on your blood results, your symptoms, your medical history, and how urgently you need to feel better. It starts with knowing your numbers: a ferritin blood test shows exactly where your iron stores stand. It's not a decision you need to make alone.

At IronOx Clinic, every patient starts with a consultation with Dr. Ros. She'll review your blood results, assess your situation, and recommend the most appropriate treatment: whether that's an infusion or something else entirely.

No GP referral is needed. Bring your recent blood results if you have them: if not, we can arrange blood testing for you.

Want to go further? Every IronOx infusion includes one complimentary hyperbaric oxygen therapy session as part of IronOx Therapy, with the option to add a 10-session Recovery Pack: two complementary pathways to oxygen delivery, one clinic.

Sources

• NHS, Iron deficiency anaemia: the NHS overview of symptoms, the full blood count used to diagnose it, and the pathway of establishing the cause before treating with iron tablets.
• NHS, Iron (vitamins and minerals): the UK reference intakes quoted above: 8.7 mg a day for men aged 19 and over, 14.8 mg a day for women aged 19 to 49, and 8.7 mg a day for women aged 50 and over.
• NICE CKS, Anaemia: iron deficiency: the primary care assessment and management pathway UK GPs work to, including investigation of the underlying cause and when specialist referral is indicated.
• British Society of Gastroenterology, Guidelines for the management of iron deficiency anaemia in adults (2021): the UK specialist guideline: why the cause of iron deficiency must be established rather than the deficiency simply replaced.

Medically reviewed by Dr Rukhsana Jabar ("Dr Ros"), GMC-registered doctor (GMC 7265326).