What do the states mean?+
- Solid: well studied, and it works.
- Half-there: the science is still forming.
- A ghost: almost no real studies.
- Hollow: well studied, and it does not work.
- A cord: the pair itself has been tested together.
- Air: nobody has ever tested this pair.
The full scoring method: How we score
Copper benefits: where the science stands
For heart: not settled yet.
On heart, the strongest evidence says it does not help: two trials, plus two crossover trials, 36 people in all found no real difference. As of August 2026, the verdicts on this page rest on evidence from 21 trials, drawn from the strongest research among the 2,275 papers on PubMed that mention copper. Every claim is checked below.
2,275 papers on PubMed · evidence from 21 trials · 1 caution
Claim by claim
- HeartThe science is still forming. No real difference found so far.
- CholesterolThe science is still forming. No real difference found so far.
- Memory and focusThe science is still forming. No real difference found so far.
- Performance and vitalityThe science is still forming. No real difference found so far.
Pairs people ask about
The seven sources we read
- 1997Crossover trial · 20 people · no clear effect on heartsource
- 2000Randomized trial · no clear effect on heartsource
- 2005Crossover trial · 16 people · no clear effect on heartsource
- 2012Randomized trial · no clear effect on heartsource
- 2012Meta-analysis · pools 11 trials · no clear effect on memory and focussource
- 2019Meta-analysis · no clear effect on performance and vitalitysource
- 2021Meta-analysis · pools 5 trials, 176 people · no clear effect on cholesterolsource
Chosen as the strongest evidence out of 2,275 papers on PubMed. Every row links to its paper.
Fair questions
Does copper work?+
For heart, it is not settled. No real difference found so far.
Is copper safe?+
One caution is recorded: Searching 21 health outcomes returned no trial of copper on its own for any of them. This is not the same as a supplement nobody has studied. Copper is a nutrient your body needs, and there is research on it. What that research is about is deficiency after bariatric surgery, air pollution exposure, and multi-mineral formulations. None of it tells you whether taking extra helps someone who already gets enough.
Why only 7 sources, when PubMed lists 2,275?+
The 2,275 is every paper that mentions copper in any way: animal studies, blood measurements, papers where it is a side note. The strongest sources are combined reviews, and each one already gathers every trial its authors could find. Our 7 cover 21 trials between them, and every one is linked above. Both counts are measured, not estimated.