Iodine (from Kelp or Potassium Iodide) vs Iron Bisglycinate

Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.

Iodine (from Kelp or Potassium Iodide)Iron Bisglycinate
CategoryMineralsMinerals
Standard Dose150-300 mcg daily (RDA: 150 mcg; upper range for optimization)25-36mg elemental iron (as bisglycinate) daily for deficiency correction
TimingMorning with food.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 DurationongoingUntil ferritin >50 ng/mL, then reassess (typically 3-6 months). Not for ongoing supplementation unless chronic blood loss.
Evidence Levelstrong_humanstrong_human

Mechanism

Iodine is the essential substrate for thyroid hormone synthesis. Thyroid peroxidase (TPO) uses iodine to iodinate tyrosine residues on thyroglobulin, producing monoiodotyrosine (MIT) and diiodotyrosine (DIT), which couple to form T4 (3,5,3',5'-tetraiodothyronine) and T3 (3,5,3'-triiodothyronine). Iodine is concentrated by the sodium-iodide symporter (NIS) in the thyroid, breast tissue, gastric mucosa, salivary glands, and choroid plexus. Beyond thyroid function, iodine has direct antimicrobial properties, modulates immune function, and may play a role in breast tissue health via iodolactone-mediated apoptosis.

Standard Dosing

150-300 mcg daily (RDA: 150 mcg; upper range for optimization)

Timing

Morning with food.

Cycle Duration

ongoing

Side Effects

  • Thyroid dysfunction (both hypo and hyper)
  • Metallic taste
  • GI upset
  • Acne
  • Salivary gland swelling
  • Thyroid autoimmunity flare

Contraindications

  • Hashimoto's thyroiditis (without selenium preloading and careful monitoring)
  • Graves' disease
  • Autonomous thyroid nodules
  • Amiodarone therapy
  • Dermatitis herpetiformis

Best Stacking Partners

Selenium (CRITICAL — must precede or accompany iodine supplementation)Vitamin CZincTyrosine

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

Best Stacking Partners

Vitamin C (doubles non-heme iron absorption)B12 (if concurrent deficiency)Folate

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