Copper

Copper
Chemical formula	Cu
Solubility
Bioavailability
Dietary sources	Oysters, shrimp, liver, mushrooms, cocoa
RDA (adults 19–50 y)	900 µg/day (US adult)
Upper limit	10 mg/day (US adult)

Copper (Cu) is a trace mineral needed for cytochrome oxidase, connective tissue, and pigment formation. Ray Peat emphasized copper–Iron balance: deficiency lets tissues retain excess iron; excess iron blocks copper uptake.

Copper is the crucial element for producing the color in hair and skin, for maintaining the elasticity of skin and blood vessels, for protecting against certain types of free radical, and especially for allowing us to use oxygen properly for the production of biological energy.

— Ray Peat

History

Etymology

The English name traces through Latin cuprum, shortened from aes Cyprium ("metal of Cyprus"), since the island of Cyprus was a major Roman-era copper source.

Copper is one of the first metals humans worked, mined and smelted since roughly 9000 BCE; its use gives the Copper Age (Chalcolithic) its name.

Structure/Chemical properties

Copper cycles between Cu⁺ and Cu²⁺ in enzymes including cytochrome c oxidase (complex IV of respiration). Peat linked copper loss with age to rising tissue iron and greater Vitamin E need.

Function/Mechanism of Action

Adequate copper supports mitochondrial oxygen use and elastic tissues. Low copper impairs substantia nigra function in Parkinson's disease. Thyroid activity increases copper absorption in osteoporosis.

Medical uses/Effects

Shellfish (oysters, shrimp) are Peat's preferred copper sources to prevent iron overload patterns. Pairing Liver with oysters balances zinc-to-copper ratios per community mineral notes on Zinc.

I made it myself, soaking a piece of pure copper with aspirin in water, until a very pale blue color developed. Later, the solution became a deeper blue color, and at a certain concentration I think it's toxic.

— Ray Peat

Side/Adverse effects

Excess supplemental zinc induces copper deficiency via metallothionein (standard nutrition; see Zinc). High-dose isolated copper supplements risk imbalance; Peat favored food sources.

Dosing

No fixed supplement dose given. Regular shellfish and balanced meals with limited fortification iron support the copper side of the iron–copper axis. See Harm reduction.