Iron (bisglycinate): evidence, dose and safety
Iron is a mineral carried in haemoglobin in red blood cells. We use ferrous bisglycinate, iron bound to the amino acid glycine, which tends to cause fewer stomach complaints than ferrous sulphate.
At a glance
- Strongest evidence
- A Strong
- Dose in our plans
- 15 mg every other day for adults
- Adult upper limit
- 40 mg a day from food and supplements together
- Safety checks
- 4 situations and 6 medicine or supplement interactions, checked against your answers in every plan
- Reviewed
- Atrum Labs clinical team (MD, PhD), November 2026
Authorised EU health claim
Iron contributes to the reduction of tiredness and fatigue.
What the research looked at
Each line is one body of research, graded A (strong) to D (weak). How we grade evidence. What each study measured is explained in your personal plan.
| Grade | Who was studied | References |
|---|---|---|
| A | Iron-deficient adults |
|
| B | Menstruating women with low ferritin |
|
| C | Iron-deficient women |
|
How much
- Our plans usually use 15 mg every other day for adults. The exact dose depends on your lab results, age and medicines.
- Adult upper limit: 40 mg a day from food and supplements together. Source: EFSA NDA Panel 2024 iron safe level of intake.
- Children's doses are set by age, and some ingredients are for adults only.
Who should not take it, or should check first
- A clinician checks first. Accidental iron overdose is a leading cause of poisoning deaths in young children; pediatric iron needs clinician review.
- Not suitable. Iron overload disorder.
- Not suitable. Ferritin above 150 ug/L (women) or 200 ug/L (men) can mean iron overload; iron must not be added.
- Not suitable. Men and women over 50 rarely need iron and are at risk of overload (hereditary haemochromatosis is common in Northern Europe); iron only after a ferritin test.
Medicines and other supplements
- Take with care. Take iron at least 4 hours apart from levothyroxine.
- Take with care. Iron binds quinolones and tetracyclines. Take ciprofloxacin at least 2 hours before or 6 hours after it (moxifloxacin 4 and 8 hours; tetracyclines 2 to 3 hours apart).
- Take with care. Iron stops oral bisphosphonates being absorbed. Take the bisphosphonate on waking with water, at least 30 minutes (ibandronate 60) before this sachet, any food or other medicine.
- A clinician checks first. Iron lowers levels of HIV integrase inhibitors (dolutegravir, bictegravir, raltegravir), which risks treatment failure and resistance. Timing must follow the HIV medicine's label.
- Take at a different time. Calcium reduces non-heme iron absorption.
- Take at a different time. Iron and zinc compete for absorption when taken together without food.
Your plan is checked against every medicine you tell us about. If you take a medicine, ask your pharmacist or doctor before starting a new supplement.
Products with Iron (bisglycinate)
Written and reviewed by the Atrum Labs clinical team (physician-scientists, MD, PhD) from our clinical knowledge base, version 0.2.0-draft. This page is general information, not medical advice. Food supplements are not a substitute for a varied, balanced diet and a healthy lifestyle.
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