Dispelling the Myth: Why You Can't Take Zinc and Magnesium Together at High Doses

October 3, 2025 •

4 min read

A common misconception in nutrition is that zinc and magnesium cannot be taken together due to absorption competition, but this concern is only relevant at extremely high dosages. At standard, recommended doses, taking zinc and magnesium together is not only safe but can be beneficial, as they often work synergistically to support various bodily functions. This article will delve into the science behind this powerful mineral duo, separating fact from fiction and offering practical advice.

Quick Summary

Most people can safely take zinc and magnesium supplements together, with many products, such as ZMA, combining them. The potential for absorption interference only arises with excessively high zinc doses. Strategic timing can optimize benefits, and separating intake is a precautionary measure rather than a necessity at normal levels.

Key Points

Misconception Alert: The belief that you can't take zinc and magnesium together is largely a myth, as they do not compete for absorption at normal dietary or supplemental levels.
High-Dose Exception: The only documented absorption issue occurs with excessively high zinc intake ($>142$ mg per day), a level far beyond standard recommendations.
Synergistic Relationship: Taken together, zinc and magnesium can provide enhanced benefits, supporting immune function, improving sleep quality, and boosting athletic performance.
Timing is Strategic, Not Mandatory: For maximum benefit, some people separate intake (e.g., magnesium at night for relaxation, zinc in the morning with food), but it's not required for standard doses.
Food First: Ensure adequate intake by consuming foods rich in zinc (meat, shellfish) and magnesium (leafy greens, nuts, seeds) before relying solely on supplements.
Professional Guidance: Consult a healthcare provider before beginning any new supplement regimen to determine the appropriate dosage and to rule out potential interactions with other medications.

The Origins of the Zinc and Magnesium Myth

The idea that zinc and magnesium shouldn't be taken together stems from the well-documented phenomenon of mineral competition. Many minerals, when consumed in large quantities, compete for the same absorption pathways in the intestines, which can reduce the bioavailability of one or both minerals. This is notably the case with iron and zinc, or calcium and magnesium. However, research indicates that this competitive relationship does not occur between zinc and magnesium at standard supplemental dosages. The only time a conflict arises is when zinc is taken in abnormally high doses, far exceeding the tolerable upper intake level (UL) of 40 mg per day.

The High-Dose Exception

Studies show that a very high dose of zinc—specifically, around 142 mg per day—can interfere with the body's ability to absorb magnesium. For perspective, this is significantly more than the typical daily recommendation of 8–11 mg for adults. Unless you are undergoing specific high-dose therapy under a doctor's supervision, this level of intake is not something the average supplement user will encounter. For those taking standard doses of 10–30 mg of zinc, co-supplementation with magnesium is not an issue.

The Synergistic Benefits of Zinc and Magnesium

Far from being antagonistic, zinc and magnesium have a synergistic relationship that provides enhanced benefits, especially when taken together at appropriate doses. This combination is a core component of ZMA supplements, which are popular among athletes and fitness enthusiasts for their complementary effects.

Enhanced Immune Function: Both minerals are crucial for a robust immune system. Zinc supports the function of immune cells, while magnesium helps regulate various immune responses. Together, they can offer powerful immune support.
Improved Sleep Quality: Magnesium is well-known for its calming properties, aiding in relaxation and sleep by regulating neurotransmitters. Zinc can further enhance these effects, and some studies suggest the combination can improve sleep quality, particularly for individuals with insomnia.
Boosted Athletic Performance and Recovery: For athletes, magnesium aids in muscle contraction and recovery, while zinc supports tissue repair and muscle growth. The combination can improve strength, endurance, and overall physical performance.
Supports Bone and Metabolic Health: Zinc and magnesium both play vital roles in bone health and density. Additionally, they both contribute to metabolic health by aiding in blood sugar control and insulin sensitivity.

Comparison of Zinc and Magnesium Supplementation


Feature	Zinc	Magnesium	Both (at normal doses)
Primary Role	Immune function, wound healing, protein synthesis, cognitive function.	Muscle relaxation, nerve function, energy production, bone health.	Enhanced immune function, sleep, athletic performance, metabolic health.
Absorption	Best absorbed on an empty stomach, but can cause nausea. Absorption inhibited by phytates in grains and legumes.	Can be taken with or without food. Some forms (e.g., citrate) may cause digestive upset.	Generally safe together. No competition for absorption at typical doses.
Recommended Timing	Often taken in the morning or with a meal to avoid nausea. Can be taken in the evening for sleep benefits.	Can be taken any time. Often taken at night for relaxation and sleep. Can be taken in the morning for stress management.	If aiming for specific timing (e.g., nighttime for sleep with magnesium), taking separately is an option, though not required.
Separation Needed?	Yes, if taking excessively high zinc doses ($>142$ mg).	No competition with zinc at normal doses. Can compete with calcium at high doses.	Only necessary at excessively high zinc levels; otherwise, can be taken together.

Sourcing Your Minerals: Food vs. Supplements

Food Sources for Zinc and Magnesium

Zinc-Rich Foods
- Oysters (highest source) and other shellfish like crab and lobster.
- Red meat (beef and lamb) and poultry.
- Dairy products, such as milk and cheese.
- Fortified breakfast cereals.
- Legumes like chickpeas, lentils, and beans.
- Nuts and seeds, including cashews, almonds, and pumpkin seeds.
Magnesium-Rich Foods
- Leafy green vegetables like spinach and kale.
- Nuts and seeds, including almonds, cashews, pumpkin seeds, and chia seeds.
- Legumes such as black beans, lentils, and chickpeas.
- Whole grains like quinoa, brown rice, and oats.
- Dark chocolate (70% cocoa or higher).
- Avocados and bananas.

Maximizing Absorption and Supplementation

When using supplements, strategic timing and food pairings can help maximize the benefits of both zinc and magnesium.

Time of day: Consider taking magnesium supplements in the evening, particularly forms like magnesium glycinate known for their calming effects, to support sleep. Zinc can be taken with a meal earlier in the day to prevent potential stomach upset, as it's better absorbed with food for many people. This automatically separates the doses and leverages their specific benefits.
Food with supplements: If you experience nausea from zinc, taking it with a meal is a good strategy. Magnesium can also be taken with food to reduce the risk of digestive discomfort. Be mindful that high-fiber foods and phytates can reduce zinc absorption, so spacing out intake from whole grains might be helpful.
Consult a professional: Before starting any new supplement regimen, it's always best to consult a healthcare provider. They can help determine the right dosages and timing based on your individual needs and other medications you might be taking.

Conclusion

The notion that you can't take zinc and magnesium together is a widespread myth that applies only in highly specific circumstances involving excessive zinc supplementation. For the average person, consuming recommended doses of these essential minerals together is not only safe but can be beneficial due to their synergistic relationship. Rather than worrying about competition, focus on strategic timing—such as taking magnesium at night for relaxation and zinc with food during the day for immune support—or opt for a combined ZMA supplement to support your overall health and well-being. Ultimately, getting adequate amounts of these minerals, whether from a balanced diet or supplementation, is what matters most for reaping their wide-ranging benefits. For more information on dietary minerals, visit the National Institutes of Health (NIH) Office of Dietary Supplements fact sheets.

Frequently Asked Questions

Yes, it is generally safe to take zinc and magnesium supplements together. The potential for reduced absorption only becomes a concern at excessively high doses of zinc, far above the typical recommended intake.

At standard supplemental doses, zinc and magnesium do not compete with each other for absorption in the intestines. However, extremely high doses of zinc (over 142 mg per day) can potentially interfere with magnesium absorption.

Zinc is often best taken with food to prevent nausea, which can occur when taken on an empty stomach. Some people prefer to take it in the morning, while others take it in the evening to potentially aid sleep and tissue repair.

Magnesium can be taken at any time of day, but many prefer taking it in the evening, particularly forms like glycinate, for its calming and sleep-promoting effects. Taking it with food can also help minimize any digestive discomfort.

Taking these minerals together can enhance their combined benefits, including improved immune function, better sleep quality, increased athletic performance and recovery, and support for bone and metabolic health.

ZMA is a popular supplement that contains zinc, magnesium, and vitamin B6. It is based on the synergistic relationship of these minerals and is often used by athletes to support muscle recovery and sleep.

Zinc should be taken at a different time from high doses of calcium and iron, as these can interfere with its absorption pathways. A common recommendation is to separate their intake by at least two hours.