Supplement Label Index

Copper Citrate vs. Copper Sulfate

Among 3,989 on-market copper products with an identifiable primary form, 10.6% use Copper Citrate (423 products) and 8.4% use Copper Sulfate (336).

Copper CitrateCopper Sulfate
Quality tierTier 2Tier 2
Copper by weight35.3%25.4%
Share of market10.6%8.4%
On-market products423336
Median declared dose1,000 elemental mcg
middle half: 334–2,000
1,650 elemental mcg
middle half: 900–2,000
Most common brandsUltima, Metagenics, Source NaturalsNature's Way, 21st Century, GNC Women's Ultra Mega

Doses are declared per serving in elemental mcg. “By weight” is the share of the ingredient that is the nutrient itself (e.g. elemental magnesium in a magnesium salt).

Why Copper Citrate is tier 2

Marketed as a bioavailable organic copper salt; no direct human comparative bioavailability RCT located.

Source: uncertain -- needs review

Why Copper Sulfate is tier 2

Used as the reference/comparator form in most animal copper-bioavailability research; highly soluble but not shown superior to organic/chelated forms.

Source: animal comparator evidence, PMID 7883634, not a human RCT

Tiers summarize published comparative bioavailability or outcome evidence for each form (see methodology). This page describes the market; it is not a recommendation to take either form. Talk to a clinician about what's right for you.

Other copper comparisons