Cupric Oxide vs. Copper Sulfate
Among 3,989 on-market copper products with an identifiable primary form, 12% use Cupric Oxide (478 products) and 8.4% use Copper Sulfate (336).
| Cupric Oxide | Copper Sulfate | |
|---|---|---|
| Quality tier | Tier 3 | Tier 2 |
| Copper by weight | 79.9% | 25.4% |
| Share of market | 12% | 8.4% |
| On-market products | 478 | 336 |
| Median declared dose | 2,000 elemental mcg middle half: 1,600–2,000 | 1,650 elemental mcg middle half: 900–2,000 |
| Most common brands | GNC Women's Ultra Mega, GNC Mega Men, Vitamin World | Nature'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 Cupric Oxide is tier 3
Provides essentially no bioavailable copper relative to CuSO4 per chick/rat data.
Source: Baker DH. 1999, J Nutr 129:2278-9, PMID 10573563
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
- Copper Gluconate vs. Copper Amino Acid Chelate
- Copper Gluconate vs. Cupric Oxide
- Copper Gluconate vs. Copper Citrate
- Copper Gluconate vs. Copper Sulfate
- Copper Amino Acid Chelate vs. Cupric Oxide
- Copper Amino Acid Chelate vs. Copper Citrate
- Copper Amino Acid Chelate vs. Copper Sulfate
- Cupric Oxide vs. Copper Citrate
- Copper Citrate vs. Copper Sulfate