Magnesium is a popular supplement used to help with sleep. Combining magnesium with other sleep aids, like melatonin and Benadryl (diphenhydramine), may offer further relaxation effects. However, there are some side effects and interactions to know.
Supplement, over-the-counter (OTC), and prescription sleep aids are often used to help improve your relaxation and sleep quality. Examples of popular sleep aids include:
- Supplements, like magnesium, zinc, L-theanine, and valerian root
- OTC drugs, like melatonin, Benadryl/ZzzQuil (diphenhydramine), and Unisom (doxylamine)
- Prescription medications, like Ambien (zolpidem), Lunesta (eszopiclone), and trazodone
The way these products help with sleep depends on how they work in your body. This means that safely taking multiple products may be useful. For example, melatonin and magnesium affect your sleep in different ways. Melatonin helps regulate your sleep hormone cycles, while magnesium helps relax your muscles and nerves. Magnesium also helps calm your nervous system, which can promote relaxation.
Studies have found that magnesium helps you fall asleep more quickly, though it does not help you stay asleep. Using other supplements along with magnesium may help improve your sleep quality. For example, a 2023 study found that taking a combination of magnesium, L-tryptophan, glycine, tart cherry, and L-theanine for three days improved sleep quality.
A 2024 study found that taking 200 milligrams of magnesium and melatonin at night for four weeks helped people fall asleep 17 minutes quicker. It also reduced the number of times the participants woke up in the night and improved their overall sleep quality.
The most concerning side effect when taking any sleep aids is increased drowsiness and sedation. The risk for this increases if you are taking more than one sleep aid. Other side effects may include lower coordination, difficulty waking up, and tiredness the next day. These are especially dangerous if you are driving or operating heavy machinery.
High magnesium doses can also cause side effects, like diarrhea, nausea, and stomach pain. The tolerable upper intake level for magnesium is 350 milligrams a day. Doses higher than this can raise your risk for side effects. Do not take more than the recommended dosage of magnesium unless recommended by a healthcare provider.
Overall, magnesium at the recommended dose is safe and does not have many side effects. However, the supplement may interact with other medications and sleep aids. For example, high doses of zinc (larger than 142 milligrams a day) or high dietary intake of zinc (over 53 milligrams daily) can lower how well your body absorbs magnesium. This absorption issue may negatively affect your bone health.
However, magnesium does not generally interact with other sleep aids. The most important concern would be the raised risk for drowsiness and sedation.
Medications that may interact with magnesium include:
- Sinemet: Sinemet (levodopa/carbidopa) is a medication used to treat Parkinson’s disease. Magnesium can lower how well the drug works in your body, causing you to have more Parkinson’s-related symptoms.
- Certain diuretics: Diuretics used to treat cardiovascular disease and help your body get rid of fluids can raise magnesium levels in your body. Examples of these medications include Aldactone (spironolactone) and Inspra (eplerenone).
- Renvela: Renvela (sevelamer) is a medication used to treat high phosphorus levels in people receiving dialysis. The medication can also raise your magnesium level.
High magnesium doses can affect how well your body absorbs other medications. This is commonly seen with certain antibiotics, like ciprofloxacin and Vibramycin (doxycycline), Neurontin (gabapentin), and bisphosphonates used to treat osteoporosis.
The type of magnesium you use can also affect how well the product is absorbed in your body. Magnesium glycinate is often recommended for sleep because of how well the product is absorbed by the body. This also means that you experience less side effects, like upset stomach and diarrhea. Magnesium L-threonate also easily moves into the brain, helping with cognitive function and sleep quality.
The time you take certain sleep aids can affect how well they actually help you sleep. In general, it is okay to take magnesium at any time of day. However, most recommend taking the product before bedtime for best results. Taking a sleep aid 30 to 60 minutes before bed is ideal to get the best night’s sleep.
You should take melatonin at night (or right before you want to fall asleep) to help mirror your body’s natural sleep-wake cycle. To avoid feeling too drowsy or tired, separate when you take supplements or medications known to cause sedation. For example, if you are taking a prescribed medication and a supplement, you could take the supplement first, and then take the prescribed medication after about an hour. Talk with a healthcare provider to decide when is the best time for you to use a sleep aid.
Always start with the lowest dose that works for you. Also, your body may become more tolerant of certain sleep aids the longer you use them. This means the same dose may not work as well for you over time. For example, there is evidence that Benadryl (diphenhydramine) builds tolerance after just three days of use. Melatonin also builds tolerance with repeated use.
Talk with a healthcare provider to decide which dose of a sleep aid is best for you based on your needs and medical history.
Good sleep is needed for your health and well-being. Other ways to improve your sleep quality may include:
- Go to bed and wake up at the same time every day
- Exercise regularly
- Eat a balanced, nutritious diet
- Establish a relaxing bedtime routine
- Limit or avoid any screens or electronic devices at least 30 minutes before bed
- Keep your bedroom quiet and at a cool temperature
- Limit or avoid caffeine in the afternoon and evening
- Limit or avoid large meals and alcohol before bedtime
Talk with a healthcare provider if you have questions about ways to improve your sleep quality.
