Iron supplements come with practical questions: what's ferrous fumarate, how does it compare with ferrous sulphate, why take iron with vitamin C, can you take it at night, and why is folic acid often included? This guide answers them — with iron's authorised claims stated correctly.
For transparency: iron is a mineral with authorised UK health claims (it contributes to the reduction of tiredness and fatigue, normal oxygen transport, and normal formation of red blood cells). We use that wording. Suspected iron deficiency, though, is a matter for your GP and a blood test — not self-diagnosis.
What is ferrous fumarate?
Ferrous fumarate is a common, well-established form of iron used in supplements — iron bound to fumaric acid. It provides a relatively high proportion of elemental iron and is widely used and generally well-tolerated. It's the form in our Iron tablets.
Ferrous fumarate vs ferrous sulphate: what's the difference?
Both are effective, well-used iron salts; the differences are practical:
- Ferrous sulphate — the traditional, very common form, effective but associated by some people with more digestive side effects.
- Ferrous fumarate — another well-absorbed form, which some people find a little gentler, though tolerance is individual.
Honestly, individual tolerance varies more than the form alone, and the dose matters a great deal — we cover gentleness and side effects in iron without constipation.
Why take iron with vitamin C?
This is a genuinely useful, evidence-based pairing: vitamin C enhances the absorption of non-haem iron (the form of iron in supplements and plant foods). Taking iron alongside vitamin C — or a vitamin-C-rich food/drink — supports better absorption. That's exactly why our iron formula includes vitamin C, which also has its own authorised role in increasing iron absorption.
Iron and folic acid: why together?
Iron and folic acid are frequently combined, particularly in formulas aimed at women of childbearing age, because both are nutrients of particular relevance in that context (folic acid contributes to normal blood formation and is especially important before and during early pregnancy). Our formula also includes B12, which works with folate in red blood cell formation. These are complementary authorised roles — a sensible, recognisable combination.
Can you take iron tablets at night?
You can take iron at whatever time suits you, but a few practical points: iron is often best absorbed on an emptier stomach, yet that's also when it's most likely to cause stomach upset — so many people take it with a little food and vitamin C. Some find taking it at night helps if it unsettles their stomach during the day. The key is consistency and tolerability. Note iron should be separated from tea, coffee, dairy and calcium supplements, which can reduce its absorption.
An important note on iron
Iron is one supplement where more is definitely not better — excess iron is harmful, and you shouldn't take iron long-term without reason. If you suspect low iron or anaemia (often from tiredness), the right step is a GP blood test to confirm it before supplementing at treatment levels. We discuss this in how to increase ferritin.
The takeaway
Ferrous fumarate is a well-absorbed, widely-used iron form; it and ferrous sulphate are both effective, with tolerance varying by person; vitamin C genuinely aids iron absorption (hence the pairing); iron and folic acid/B12 are complementary; and timing is about tolerability — but always confirm low iron with your GP first. For tiredness causes, see what vitamins help with tiredness.
Food supplements should not be used as a substitute for a varied, balanced diet and a healthy lifestyle. Do not take iron supplements long-term without medical advice; suspected iron deficiency should be confirmed by your GP with a blood test. Keep iron out of reach of children — accidental overdose is dangerous. If you are pregnant, breastfeeding, taking medication or managing a medical condition, speak to your GP or pharmacist first. Signed, Dr. Miron, Founder of Pure Vitamins UK.
