Ferrous bisglycinate is a chelated form of iron — meaning the iron molecule is wrapped inside two glycine amino acids to protect it through digestion and help it absorb more efficiently in the small intestine. Unlike cheaper iron forms like ferrous sulfate, it bypasses many of the gut irritation issues that make people quit iron supplementation. It delivers elemental iron directly where your body needs it without the collateral digestive damage.

Because the iron is chelated to glycine, it travels through the stomach mostly intact and gets absorbed through a dedicated amino acid transport pathway in the intestinal wall — not just the standard iron absorption route. This means it absorbs better even when stomach acid is low, and it causes far less oxidative irritation to the gut lining. Once absorbed, it enters the bloodstream and is used to make hemoglobin in red blood cells, restore ferritin (iron storage) levels, and support dozens of iron-dependent enzyme processes.

Capsules and tablets are most common for adults. Liquid drops are popular for infants, toddlers, and anyone with swallowing difficulties. Powder forms can be added to food or drinks. Gummies exist but often contain lower elemental iron doses. For therapeutic iron repletion, capsules or tablets are most reliable for hitting consistent daily targets.

• Iron deficiency anemia
• Low iron / low ferritin
• Fatigue and low energy
• Pregnancy iron needs
• Heavy menstrual bleeding
• Restless leg syndrome
• Hair thinning and hair loss
• Athlete performance and endurance
• Cognitive fog and poor concentration
• Pediatric iron deficiency

• Iron-deficiency anemia in pregnancy (well-supported by clinical guidelines and multiple trials showing routine iron supplementation prevents gestational anemia)
• Cognitive and developmental delays in iron-deficient infants and young children (early iron correction during critical windows supports normal neurodevelopment)
• Exercise-induced iron deficiency in endurance athletes (regular supplementation offsets accelerated iron losses in high-training populations)

• Beef liver — One of the richest sources of heme iron on the planet — the form your body absorbs most efficiently (15–35% absorption vs. 2–10% for plant iron). A 3 oz serving delivers around 5 mg of highly bioavailable iron.
• Oysters and clams — Shellfish, especially clams, are extraordinarily iron-dense — a small serving of clams can provide more than 100% of your daily iron needs in heme form, which absorbs readily.
• Grass-fed beef (red meat) — A reliable everyday source of heme iron. Red meat also contains a protein factor that boosts absorption of non-heme iron from other foods eaten in the same meal, making it doubly useful.
• Lentils and legumes — The best plant-based iron source — a cup of cooked lentils provides around 6–7 mg of non-heme iron. Pair with vitamin C to meaningfully improve absorption of this form.
• Pumpkin seeds (pepitas) — A practical plant-based option with around 2–3 mg of iron per ounce, plus magnesium and zinc. A good daily snack for vegetarians working to maintain iron levels through diet.

• Dark or greenish stools (normal — caused by unabsorbed iron, not a health concern)
• Mild nausea if taken on a completely empty stomach in sensitive individuals
• Constipation at higher doses (much less common than with ferrous sulfate)
• Stomach cramping if doses are very high
• Metallic taste in mouth (occasional, particularly with liquid forms)
• Teeth staining with liquid drops if not diluted or rinsed after (use a straw)

• Recommended daily: Treatment of iron deficiency: 25–36 mg elemental iron per day (1–2 capsules of a standard ferrous bisglycinate product). Maintenance and prevention: 14–18 mg elemental iron per day. Pregnancy: 27 mg elemental iron per day (standard recommendation, often met by prenatal vitamins). Pediatric dosing varies by age and weight — always use a pediatrician's guidance for children.
• Best time of day: Iron absorbs best in the morning, ideally mid-morning when stomach acid is active. Taking it away from other supplements and meals improves absorption, though ferrous bisglycinate is more flexible than other forms in this regard.
• With or without food: Can be taken with a small amount of food if plain stomach is not tolerated — ferrous bisglycinate tolerates food better than most iron forms. Avoid taking with high-calcium meals, coffee, tea, or large grain-heavy meals. A small vitamin C source (orange juice, kiwi) taken alongside can further boost absorption.
• Time to effect: Ferritin and hemoglobin levels typically begin rising within 2–4 weeks. Most people feel noticeably better — more energy, less brain fog — within 4–8 weeks. Full replenishment of iron stores after deficiency usually takes 3–6 months of consistent daily use.
• How long to take it: For confirmed iron deficiency, continue for at least 3–6 months to fully replenish stores, even after blood counts normalize. Have ferritin levels tested before, during, and after supplementation. Once stores are adequate, reassess diet and ongoing needs — do not continue high-dose iron indefinitely without confirmation of ongoing deficiency. Do not supplement iron without confirmed deficiency or clinical guidance, as excess iron has its own health risks.