Iron

aka ferrite or ferritin.

Vitamin c aids absorption.

Mineral.

Red blood cell production, hemoglobin ...

Note

Delay taking any supplements for 30-60 minutes after consuming coffee as it contains compounds (polyphenols) that limit the absorption of many micronutrients.

Do not take with milk or other dairy products (or over consume them) as the calcium they contain inhibits absorption.¹

Forms/Types

There are quite a few forms of iron/ferrite, here they are in descending order of bioavailability;

ferrous bisglycinate - the best option for general supplementation - highly bioavailable and well tolerated so less likely to cause stomach upset and constipation
ferrous pyrophosphate - slightly lower bioavailability and tolerance than ferrous bisglycinate, often used for food fortification as it is highly stable and a low taste or odour impact
ferrous gluconate - contains very little elemental iron
ferrous sulphate - often used for those iron anaemia - may cause oxidative damage, stomach upset and constipation
ferrous fumarate - low bioavailability and may cause stomach upset and constipation

Quality

As with all supplements - buyer beware. It's quite common for supplements to be contaminated with a variety of impurities, often in the form of heavy metals, and/or contain far more or less of the ingredients stated on the label. There's no simple rule of thumb to avoid this, such as avoiding cheap or imported products; expensive or well-known brands produced in-country may be just as bad. Ideally you should take some time to find products (if you can) that;

have been laboratory tested on behalf of the manufacturer by a reputable body or company that operates in your country or region (here's an example of a Peak Supps creatine supplement available on Amazon in the UK which has been tested by Eurofins: Creatine Monohydrate Powder 1Kg | Pure Micronised | Packaging May Vary - see pictures 3 & 4)
in the UK & EU, are manufactured in facilities that meet the minimum standards of good manufacturing practice (GMP) in their production processes (for medicines).¹² Facilities are inspected for compliance and manufacturers' product(s) must:
- be of consistent high quality
- be appropriate to their intended use
- meet the requirements of the marketing authorisation (MA) or product specification

Be wary of any manufacturers or brands making claims around these valid but irrelevant standards;

HACCP: this standard relates to food safety which indicates that the seller is claiming their supplement is a food; whilst meeting this standard is worthwhile, GMP (detailed above) would be a more appropriate standard
ISO22000: same as HACPP
ISO9001: this standard is focussed on quality control management systems in the context of managing a business or organisation, not directly on the the quality of the products that business produces (although it may have a beneficial impact)

Haemoglobin

Haemoglobin is a protein in blood that transports oxygen around your body.

To make haemoglobin it is important that you eat enough iron every day.

Dosage - How Much?

Deficiency - Too Little

Low iron levels lead to low haemoglobin which can cause many symptoms, including:

fatigue
brain fog
shortness of breath
headaches
paler than normal skin
noticeable heartbeats (heart palpitations)

More likely in those under 25, women and those with black or asian heritage, in warmer months in the UK. ³

Toxicity - Too Much

Side Effects

When to Avoid Use - Interactions/Contraindications

Iron reduces the absorption of the antioxidants in green tea.

Calcium reduces absorption.

Random Facts

References

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Last Updated: 2026-04-03