Iron Bisglycinate vs Vitamin A (Retinol)

Mechanism

Iron is essential for hemoglobin (oxygen transport), myoglobin (muscle oxygen storage), cytochrome enzymes (electron transport chain — Complexes I, II, III, IV), cytochrome P450 enzymes (drug/hormone metabolism), catalase (H2O2 decomposition), ribonucleotide reductase (DNA synthesis), and aconitase (Krebs cycle). Iron bisglycinate (Ferrochel) uses amino acid chelation to bypass the normal DMT1/ferroportin pathway, instead being absorbed intact via PepT1 transporter. This mechanism avoids the GI side effects of ionic iron (free Fe2+ generates hydroxyl radicals via Fenton reaction in the gut lumen) and is not inhibited by phytates, tannins, or calcium.

Standard Dosing

25-36mg elemental iron (as bisglycinate) daily for deficiency correction

Timing

On empty stomach or with vitamin C for absorption. Alternate day dosing (every other day) may be superior due to hepcidin cycling. Separate from calcium, zinc, tea, coffee by 2+ hours.

Cycle Duration

Until ferritin >50 ng/mL, then reassess (typically 3-6 months). Not for ongoing supplementation unless chronic blood loss.

Side Effects

• GI distress (significantly less than ferrous sulfate)
• Constipation (less common with bisglycinate)
• Dark stools
• Nausea
• Iron overload if supplemented unnecessarily

Contraindications

• Hemochromatosis
• Iron overload conditions
• Thalassemia (without documented deficiency)
• Hemolytic anemias (unless also iron deficient)
• Chronic transfusion therapy

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Mechanism

Retinol is converted to retinal (for vision, rhodopsin cycle in rod photoreceptors) and retinoic acid (for gene regulation). Retinoic acid binds RAR/RXR nuclear receptors, regulating >500 genes involved in cell differentiation, immune function, and embryonic development. It is essential for mucosal barrier integrity (gut, respiratory, skin epithelial cell turnover), T-cell differentiation (promotes Treg and Th2 over Th1/Th17), IgA secretion, and natural killer cell function. Works synergistically with Vitamin D — both share the RXR receptor as a heterodimer partner.

Standard Dosing

5000-10,000 IU retinol (1500-3000 mcg RAE) daily

Timing

With fat-containing meal. Best with vitamins D and K for synergistic fat-soluble vitamin balance.

Cycle Duration

ongoing

Side Effects

• Headache (chronic high dose)
• Dry skin/lips
• Hepatotoxicity (chronic excess)
• Hypercalcemia
• Hair loss (toxicity)
• Teratogenicity

Contraindications

• Pregnancy (>10,000 IU/day is teratogenic)
• Liver disease (hepatic storage and toxicity)
• Hypervitaminosis A
• Concurrent retinoid medication use

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