Iodine (from Kelp or Potassium Iodide) vs Magnesium L-Threonate

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

Mechanism

Magnesium L-threonate (Magtein) was specifically developed by MIT researchers to cross the blood-brain barrier efficiently. L-threonate, a metabolite of vitamin C, acts as a carrier to increase brain magnesium concentration by ~15% (compared to negligible CNS penetration from other Mg forms). Elevated brain Mg2+ enhances NMDA receptor signaling fidelity, increases synaptic density in the hippocampus and prefrontal cortex, promotes BDNF expression, and enhances both short-term and long-term memory via potentiation of pre-synaptic release probability at hippocampal CA3-CA1 synapses.

Standard Dosing

1000-2000mg magnesium L-threonate daily (providing ~144mg elemental Mg per 2000mg)

Timing

Split dose: 1 capsule morning, 2 capsules before bed (or per product label). Evening dose supports sleep and overnight memory consolidation.

Cycle Duration

ongoing

Side Effects

• Drowsiness
• Headache (initial)
• Mild GI discomfort
• Cost (significantly more expensive than other Mg forms)

Contraindications

• Severe renal insufficiency
• Myasthenia gravis

Best Stacking Partners