Magnesium is a natural sedative that helps your muscles relax, says Dr Leslie Korn, a behavioural medicine clinician specialising in integrative therapies.
That’s why people take magnesium supplements if they have trouble sleeping. In fact, older adults with insomnia who took 500 milligrams (mg) of magnesium daily for eight weeks slept better, dozed off faster, and were less likely to wake up too early compared to those who didn’t the mineral, a study from Iran found.
Magnesium reduces the levels of stress hormone cortisol in your body, says Korn. As your cortisol levels fall, your melatonin—the hormone that helps you sleep—surges to help you doze off quicker and stay asleep longer.
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With your hormones sorted out and your muscles relaxed, that can help you ease into a deeper phase of sleep—the rapid eye movement (REM) sleep during which dreams occur.
While there hasn’t been any formal studies done on the vivid dream-magnesium connection, magnesium’s effect on deep sleep may be behind the anecdotal evidence in support of it, says Korn.
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According to the National Institutes of Health, if we experience interrupted sleep, or skimp on non-REM sleep, our REM sleep may be affected. That obviously cuts into your dreamtime, but can also mess with your memory and learning, since REM sleep is vital for those functions, too.
When you get a nice, uninterrupted amount of REM sleep—about 90 to 120 minutes for one entire three-phase cycle, repeated several times per night—you get more time in the third phase, when the most dreaming occurs.
And, you remember those dreams more easily, since robust REM sleep is tied to memory functions. With more prolonged dream time and better recall, what you dream tends to be more vivid, according to Korn.
Being able to tap into more REM time, then, is a big boost—and for many people, magnesium can be the rocket that gets you there.
So if you’re struggling with sleep, taking a magnesium supplement might make sense. But how much works?
The recommended daily allowance of magnesium for guys aged 19 to 30 is 400 mg per day, and 420 mg for those 31 and up.
You can get magnesium from some foods—like dark leafy greens, nuts, seeds, beans, and whole grains—but it takes some focused eating to get to that 400 mg every day. For example, a cup of spinach is just 24 mg and a whole avocado has 58 mg.
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That’s why supplementation can be handy, but be sure you choose the right kind, advises the University of Maryland Medical Centre. Magnesium in the citrate, lactate and gluconate forms is absorbed more completely than other forms.
Like many supplements, more is not always better. It’s definitely possible to experience some nasty effects from taking too much.
Symptoms of toxicity include nausea, vomiting, facial flushing, urine retention, and lethargy. It can progress to muscle weakness, irregular heartbeat, and possible cardiac arrest.
But to overdose on magnesium, you’d have to be taking very high amounts—typically more than 5000 mg per day, Korn notes. Deficiency is a much more common problem than toxicity.
This article originally appeared on Men’s Health