Calcium vs. Magnesium: Differences and When to Supplement Which

Calcium and magnesium are minerals that work together in muscles but have opposite roles – calcium triggers muscle contraction, while magnesium relaxes it. Calcium is the main building block of bones, while magnesium contributes to energy production, muscle relaxation, and recovery. Athletes often have a higher need for magnesium because they lose it more through sweat and consume it more quickly. Supplement the one you are deficient in based on symptoms and diet.

How do calcium and magnesium differ?

Both minerals are electrolytes and complement each other in the body, which is why people often confuse them.

Calcium:

• main building block of bones and teeth
• triggers the contraction of muscle fibers
• contributes to blood clotting and the transmission of nerve signals

Magnesium:

• helps muscles relax after contraction
• needed for energy production and utilization (ATP)
• supports recovery, sleep, and nerve balance

Muscle movement is a synergy of both

In simple terms: calcium gives the command to contract, magnesium subsequently allows for relaxation. When one of them is out of balance, the muscle tends to cramp – hence the connection between magnesium deficiency and muscle cramps.

For smooth muscle function, you need both in balance, not just one of them in large amounts.

Why is magnesium more critical for athletes?

Magnesium is significantly lost through sweat, and during physical exertion, the body consumes it more quickly for energy production and recovery. Additionally, its intake from regular diet is often at the lower limit for many people, even without exercise.

In contrast, most people get enough calcium from their diet, mainly due to dairy products. Therefore, for active individuals, we more often address magnesium supplementation. You can find more details in the article magnesium and sports.

Where to find them in your diet

Sources of magnesium: nuts and seeds, whole grains, legumes, leafy greens, dark chocolate, bananas.

Sources of calcium: dairy products, poppy seeds, leafy greens, some mineral waters, fish.

Some foods like leafy greens provide both. With a varied diet, you can cover both minerals without supplements.

When to supplement which

• Frequent muscle cramps, fatigue, poor sleep, intense training – consider magnesium supplementation.
• Low intake of dairy products, need to support bones – rather increase calcium intake, ideally from food.
• Not sure – refer to your diet and symptoms; supplement specifically what you are low on, not both blindly.

Calcium and magnesium can influence each other's absorption at high doses, so mega doses of both at once do not make sense. If you have kidney disease or are taking medications, consult your doctor before supplementation.

Learn more about electrolytes in a separate article.

Frequently asked questions

What is the difference between magnesium and calcium?

Calcium triggers muscle contraction and is the main building block of bones, while magnesium relaxes the muscle after contraction and contributes to energy production and recovery. They work together in muscles, and you need both in balance.

Should I take magnesium and calcium at the same time?

At high doses, they can influence each other's absorption, so mega doses of both at once do not make sense. Supplement specifically the one you are deficient in based on your diet and symptoms.

Which mineral is more important for athletes?

Athletes often have a higher need for magnesium because they lose it more through sweat and consume it more quickly, while most people get enough calcium from their diet. However, it depends on the specific diet.

Does magnesium or calcium help with muscle cramps?

Cramps are more often associated with magnesium deficiency because it helps relax the muscle. However, cramps can also have other causes, mainly fluid and sodium loss.