Iron Bisglycinate
Iron bisglycinate treats low ferritin without the constipation and GI distress of iron sulphate. Dosing for ferritin under 50 ng/mL, absorption timing, and 3-month retest protocol.
Ferritin under 30 ng/mL causes symptoms — fatigue, hair loss, poor exercise recovery, and brain fog — even when haemoglobin is "normal." Many Indian doctors only treat overt anaemia (haemoglobin below 12/13 g/dL) and overlook suboptimal ferritin. The optimal target for most individuals is 70–100 ng/mL.
Why Ferritin Matters Beyond Anaemia
Ferritin is the iron storage protein — it reflects the body's total iron reserves. Most clinical guidelines focus on haemoglobin as the anaemia marker, but haemoglobin can remain normal (maintained by drawing down ferritin stores) while ferritin is severely depleted.
Symptoms of low ferritin (30–50 ng/mL range), even with normal haemoglobin:
- Chronic fatigue — iron is required for mitochondrial energy enzymes
- Hair loss (telogen effluvium) — ferritin below 30–40 ng/mL is associated with diffuse hair thinning
- Reduced exercise performance — iron deficiency impairs VO2 max independent of anaemia
- Brain fog and poor concentration
- Restless legs syndrome
- Cold intolerance
In India, approximately 40–50% of women and 20–30% of vegetarian men have ferritin below the functional threshold — making this one of the most underdiagnosed and undertreated deficiencies.
The Iron Sulphate Problem in India
The vast majority of iron tablets prescribed in India are ferrous sulphate — the cheapest form. While inexpensive, ferrous sulphate has significant problems:
- Only ~10% bioavailability (most passes through unabsorbed)
- The unabsorbed iron irritates the gut, causing constipation, nausea, dark stools, and abdominal cramping in 30–40% of users
- GI side effects lead to poor compliance — a survey found over 50% of patients stopped or reduced their iron sulphate due to side effects
- Treatment failure from compliance is a major reason iron deficiency persists despite supplementation
Why Iron Bisglycinate is Better
Iron bisglycinate is iron chelated to two glycine molecules. The chelation provides three key advantages:
- Better absorption: 30–50% bioavailability vs 10% for sulphate. The glycinate chelation uses a separate amino acid transporter pathway, bypassing the saturatable divalent metal transporter (DMT1) that inorganic iron relies on.
- Minimal GI side effects: The chelated iron doesn't dissociate in the gut — it passes through without irritating the mucosal lining. This means no constipation, no nausea, and no dark stools in most users.
- Flexible timing: Can be taken fasted or with food, unlike sulphate which causes worse GI effects when fasted.
Iron Form Comparison
| Form | Elemental Iron | Absorption | GI Tolerance | Cost India |
|---|---|---|---|---|
| Ferrous Sulphate | ~20% | ~10% | Poor — constipation in 30–40% | Very cheap |
| Ferrous Fumarate | ~33% | ~15% | Moderate | Cheap |
| Ferrous Gluconate | ~12% | ~15% | Better than sulphate | Low-moderate |
| Iron Bisglycinate | ~14–20% | ~30–50% | Excellent — no GI effects | Moderate-high |
| Liposomal Iron | Variable | Very high | Excellent | High |
| Ferric (III) forms | Variable | ~10–15% (requires conversion) | Moderate | Variable |
Absorption Enhancers & Inhibitors
Enhancers — take with these:
- Vitamin C (ascorbic acid): Reduces ferric iron to ferrous form, which is better absorbed. 250–500mg Vitamin C alongside iron can double absorption. Take together.
- Acidic environment: Iron absorption is better in an acid stomach environment. Avoid PPIs if possible during iron repletion (discuss with physician).
Inhibitors — space 2 hours away from:
- Calcium supplements and dairy: Calcium strongly inhibits iron absorption
- Tea and coffee: Tannins chelate iron — even black tea reduces absorption by 50–70%
- Phytates: In whole grains, legumes, and bran
- Antacids and PPIs: Reduce stomach acid needed for iron absorption
Alternate Day Dosing — New Evidence
Recent research (2019–2022) has challenged the conventional daily dosing approach. When iron is taken daily, it triggers hepcidin release (the body's iron absorption regulator). Elevated hepcidin actively suppresses iron absorption for 24–48 hours after a dose.
Alternate day dosing (every other day) allows hepcidin to normalise between doses, potentially improving net absorption over the same period. This approach is particularly relevant for individuals who don't tolerate daily iron or who have had poor results with standard daily protocols. Discuss with your physician.
Timeline & Testing
Iron replenishment is slow — patience and consistency are essential:
- Ferritin typically rises 5–10 ng/mL per month on adequate protocol
- From ferritin 15 to target 70: expect 5–10 months
- Retest at 3 months to confirm trajectory and adjust dose
- Continue until ferritin is stable at target on two consecutive tests (3 months apart)
- Identify and address the root cause: menstrual losses, vegetarian diet with low bioavailability, GI blood loss, or absorption issues (celiac, H. pylori)
Frequently Asked Questions
Why choose iron bisglycinate over ferrous sulphate in India?
Iron bisglycinate has 30–50% absorption vs 10% for ferrous sulphate, and causes minimal GI side effects vs the 30–40% who experience constipation and nausea with sulphate. Poor compliance due to GI effects is the primary reason iron deficiency persists despite treatment. Bisglycinate solves both the efficacy and compliance problem. The higher cost is justified.
What is the dose of iron for low ferritin?
For ferritin 20–50 ng/mL: 18–36mg elemental iron/day as bisglycinate. For ferritin below 20 with symptoms: 36mg/day, or consider alternate-day dosing. Check elemental iron content on the label — a 325mg ferrous sulphate tablet contains only 65mg elemental iron; iron bisglycinate labels vary. Target elemental iron, not total compound weight.
How long to raise ferritin with iron supplements?
Ferritin rises approximately 5–10 ng/mL per month on an adequate protocol. From severely low (ferritin 10) to target (70+), expect 6–12 months. Retest at 3 months to confirm trajectory. Continue supplementing until ferritin is stable at target on two consecutive tests. Always identify and address the underlying cause — continued blood loss or poor absorption will prevent recovery regardless of supplementation.
Can I take iron without food?
Yes, iron bisglycinate can be taken fasted — absorption is actually highest fasted with Vitamin C. This is a major advantage over ferrous sulphate, which causes worse GI effects when taken fasted. If any GI discomfort occurs, taking with a small meal resolves it. Always space iron 2 hours away from calcium, coffee, tea, and antacids.