Yes, you can take magnesium and copper together. Most people do so without problems, and many multivitamins already combine both minerals in the same pill. That said, the relationship between these two minerals is worth understanding, because high magnesium intake over time can increase how much copper your body loses through digestion.
How Magnesium Affects Copper Absorption
Magnesium doesn’t block copper at the same transport site the way zinc famously competes with copper. The interaction is subtler. Research has shown that magnesium supplementation increases fecal losses of copper, meaning more copper passes through your digestive system without being absorbed. The practical effect: if you’re taking high doses of magnesium regularly and your copper intake is marginal, you could gradually tip the balance toward copper depletion.
This isn’t a reason to avoid combining them. It’s a reason to make sure your copper intake is adequate, especially if you’re supplementing magnesium at higher levels.
Dosages That Matter
The tolerable upper intake level for supplemental magnesium is 350 mg per day for adults. That limit applies only to magnesium from supplements and medications, not from food. Most magnesium supplements fall in the 200 to 400 mg range, so many people are right at or near the ceiling.
For copper, the recommended dietary allowance is 900 mcg (0.9 mg) per day for adults, rising to 1,000 mcg during pregnancy and 1,300 mcg during lactation. If you eat a varied diet with nuts, shellfish, whole grains, or dark chocolate, you likely get enough copper from food alone. But if your diet is limited and you’re also taking a magnesium supplement daily, it’s worth checking whether your copper intake adds up.
The Zinc Factor
The more relevant mineral interaction to watch is zinc and copper. Zinc actively competes with copper for absorption, and many people who supplement magnesium also take zinc (often in a “ZMA” or similar combination product). A large population study found that people with low zinc and high copper levels had a 2.6 times higher risk of dying from any cause and a 2.7 times higher risk of cancer mortality. That same study found that low zinc combined with low magnesium was also associated with increased mortality risk.
So the real question often isn’t just “magnesium plus copper” but how all three minerals balance out together. If you take a zinc supplement above 25 to 30 mg daily, adding a small amount of copper (1 to 2 mg) is a common strategy to prevent zinc from depleting your copper stores. Magnesium doesn’t create the same degree of competition, but it adds a mild additional pressure in the same direction.
Signs Your Copper Is Too Low
Copper deficiency is uncommon in the general population, but it does happen, particularly in people with digestive conditions, those who’ve had gastric surgery, or those taking high doses of competing minerals for extended periods. Symptoms tend to develop slowly and can be easy to miss early on:
- Persistent fatigue that doesn’t improve with rest or iron supplementation
- Frequent infections from low white blood cell counts
- Numbness or tingling in your hands and feet
- Premature graying of hair
- Pale skin unrelated to sun exposure
Left uncorrected, copper deficiency can lead to anemia, osteoporosis, elevated cholesterol, and nerve damage. These complications are serious but preventable. A simple blood test can check your copper and ceruloplasmin levels if you suspect an issue.
How to Take Them Together Safely
If you’re taking a standard magnesium supplement (200 to 350 mg) alongside a copper-containing multivitamin or a standalone copper supplement of 1 to 2 mg, you’re well within safe territory. Many clinical formulations combine these minerals without issue. The AREDS eye health supplement, for example, included 2 mg of copper alongside zinc and other nutrients, and was studied in nearly 5,000 people over several years.
Spacing them apart isn’t necessary for most people, though if you prefer to be cautious, taking them with different meals gives each mineral less competition during absorption. What matters more is consistency: if you take magnesium daily at moderate to high doses for months or years, periodically check that your diet or supplement routine includes adequate copper. Most basic multivitamins contain only small amounts of magnesium and variable amounts of copper, so reading the label is worth the 30 seconds.
The bottom line is straightforward. Taking magnesium and copper together is safe for the vast majority of people. The interaction between them is mild compared to zinc-copper competition, and it only becomes clinically meaningful when magnesium doses are high and copper intake is already low. Keeping your supplemental magnesium at or below 350 mg and ensuring you get at least 900 mcg of copper daily from food or supplements covers the bases.