Copper (as Copper Bisglycinate) vs Selenium (Selenomethionine)

Mechanism

Copper is a cofactor for critical cuproenzymes: cytochrome c oxidase (Complex IV, mitochondrial respiration), Cu/Zn-SOD (superoxide dismutation), ceruloplasmin (ferroxidase — converts Fe2+ to Fe3+ for transferrin loading; essential for iron metabolism), lysyl oxidase (collagen and elastin cross-linking), dopamine beta-hydroxylase (dopamine to norepinephrine conversion), tyrosinase (melanin synthesis), and peptidyl-glycine alpha-amidating monooxygenase (neuropeptide processing). Copper is transported by ATP7A/B (Menkes/Wilson proteins) and regulated by metallothionein and glutathione.

Standard Dosing

1-2mg elemental copper daily (when supplementing zinc >25mg)

Timing

With food. Separate from zinc by 2+ hours for optimal absorption of both.

Cycle Duration

ongoing when zinc supplementation is ongoing

Side Effects

• Nausea (on empty stomach)
• GI upset
• Metallic taste
• Copper toxicity at high doses (hepatotoxicity, hemolytic anemia)

Contraindications

• Wilson's disease (genetic copper overload)
• Copper storage disorders
• Copper excess states

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Mechanism

Selenium is incorporated as selenocysteine (the 21st amino acid) into 25 selenoproteins. Key enzymes: glutathione peroxidases (GPx1-4, reduce hydrogen peroxide and lipid hydroperoxides), thioredoxin reductases (TrxR1-3, maintain cellular redox balance), iodothyronine deiodinases (DIO1-3, convert T4 to T3 and regulate thyroid hormone metabolism), selenoprotein P (selenium transport and brain antioxidant), and selenoprotein W (muscle antioxidant). Selenium is essential for thyroid function, immune defense, reproductive health, and cancer chemoprevention.

Standard Dosing

200 mcg selenomethionine daily

Timing

With meals. Can be taken any time of day.

Cycle Duration

ongoing

Side Effects

• Garlic breath/body odor (selenosis)
• GI upset
• Hair loss and nail brittleness (toxicity)
• Fatigue
• Peripheral neuropathy (chronic excess)
• Potential type 2 diabetes risk at high doses (SELECT trial observation)

Contraindications

• Selenium excess (>400 mcg/day — narrow therapeutic window)
• Non-melanoma skin cancer history (SELECT trial concern)

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