Understanding the Interaction Between Melatonin and Magnesium

In this article, we will take a close look at the interplay between melatonin and magnesium, two popular supplements often used to improve sleep quality. We will discuss the potential benefits and risks of their co-supplementation, and the precautions one should consider. The article will also touch on their impact on specific populations and their interaction with other medications.
Natasha Puttick

Natasha Puttick

Graduate medical student at Barts and London.

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Melatonin and magnesium are both commonly used supplements that can aid in sleep. Melatonin is a hormone that regulates the sleep-wake cycle, while magnesium plays a role in nerve function and the regulation of the body's circadian rhythms. But is it safe to take these two supplements together?

Melatonin and Magnesium Interactions

From the current breadth of research, it appears that taking melatonin and magnesium together can be safe and may even have additional benefits. A study conducted on women with polycystic ovary syndrome (PCOS) found that co-supplementation of magnesium and melatonin for 8 weeks had beneficial effects on sleep quality and total testosterone levels [1]. Another study conducted on elderly residents in a long-term care facility found that the administration of melatonin, magnesium, and zinc improved the quality of sleep and life [2].

Benefits of Taking Melatonin and Magnesium Together

Melatonin and magnesium, when taken together, can offer several health benefits.

In addition to sleep improvement, the combination of melatonin and magnesium can also have positive effects on metabolic health. In women with PCOS, co-supplementation of these two substances resulted in a significant decrease in testosterone concentrations, serum insulin levels, and cholesterol levels. It also increased high-density lipoprotein cholesterol (HDL-C) levels, which is beneficial for heart health [1].

Furthermore, the combination of melatonin and magnesium can have a positive impact on mental health. A study found that magnesium supplementation, with or without vitamin B6, could provide a meaningful clinical benefit in daily life for individuals with stress and low magnesemia [3].

In conclusion, taking melatonin and magnesium together can improve sleep quality, metabolic health, and mental well-being.

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Potential Risks and Side Effects

Melatonin can cause side effects such as drowsiness, headache, and dizziness, and this includes when it is taken with magnesium [4]. In some cases, melatonin can also interact with other medications and substances, increasing the risk of bleeding when taken with blood-thinning medications [5, 6].

Melatonin may also affect blood sugar levels, which could be a concern for individuals with diabetes [5]. Furthermore, it can potentially interfere with immunosuppressive drugs and epilepsy medications, making them less effective [5].

Magnesium, on the other hand, can cause changes in circulating plasma cation levels, leading to a decrease in plasma magnesium levels [7]. This could potentially affect the body's physiological functions, although the exact implications of this are not fully understood.

Interactions with Other Medications

Both melatonin and magnesium can interact with other medications. For instance, melatonin can interact with contraceptive drugs, potentially increasing the risk of side effects [5, 6]. It's also advised to avoid taking melatonin with alcohol or caffeine as these can interfere with your sleep-wake cycle and natural melatonin production [6].

Other medications they may interact with include blood-thinning medications, epilepsy medications, immunosuppressants, diabetes medications, blood pressure medications, and contraceptive drugs [5]. Therefore, if you're taking any of these medications, it's crucial to consult with your healthcare provider before starting melatonin or magnesium supplementation.

Considerations for Specific Populations

Certain populations should exercise particular caution when considering melatonin and magnesium supplementation.Pregnant or breastfeeding individuals, as well as those planning to become pregnant, are advised to avoid taking melatonin due to limited research on its safety during these periods [5].

People with certain health conditions, such as autoimmune conditions, epilepsy, kidney disease, and liver disease, should also consult their doctor before using melatonin [5].


While melatonin and magnesium can be beneficial for sleep and other health conditions, it's important to be aware of potential risks and interactions, especially if you're taking other medications or have certain health conditions. Always consult with a healthcare professional before starting any new supplement regimen.

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Natasha Puttick

Natasha Puttick

Natasha is a medical student at Barts and the London school of Medicine and Dentistry, with an interest in the social determinants of health. She graduated from the University of Oxford with a BA in Human Sciences and has obtained two publications. Her most recent work investigating clinical vaccine trials has been published in BMJ Public Health.