Last week a new friend was telling me about her sons. She has quite a bit of anxiety about their situation and, since reaching menopause, she’s had trouble sleeping. She tried sleeping pills and didn’t like the way they made her feel. But magnesium supplements seem to do the trick.
So I looked for research evaluating magnesium’s effects on anxiety and insomnia. Not much is out there, and most of what exists are investigations of magnesium in combination with other vitamins and supplements. But some readers of this blog want information about alternative treatments for insomnia, so here’s the gist of what I found.
Magnesium’s Effects on Anxiety Symptoms
Magnesium has several important molecular functions in the body. Both animal and human studies suggest that magnesium deficiency may be linked to anxiety and anxiety-related disorders. In the early 2000s, three randomized controlled trials were conducted to assess the effects of magnesium supplements on anxiety symptoms in humans:
- In 80 healthy male subjects, a 4-week treatment of a multivitamin containing large amounts of magnesium, zinc, and calcium significantly decreased anxiety symptoms and perceived stress compared with placebo. The effects got stronger the longer treatment progressed.
- In 44 women with premenstrual anxiety (but otherwise healthy), over 4 monthly cycles each, participants were alternately given 200 mg of magnesium, 50 mg of vitamin B6, both the magnesium and the B6, or a placebo pill. The combination treatment provided a small but significant reduction in premenstrual symptoms such as nervous tension, mood swings, irritability, anxiety. By itself, however, the magnesium was no more effective than placebo.
- The third study was conducted on 264 people with a diagnosis of generalized anxiety disorder (GAD) for 3 months. The anti-anxiety effects of a compound containing magnesium and two plant extracts was compared with placebo. Both the active treatment and the placebo greatly decreased participants’ anxiety symptoms—the supplement a little more than the placebo.
These results are certainly mixed. First, it’s hard to make claims about the anxiety-reducing effects of magnesium when it’s studied in combination with other substances. It’s also important to realize that the effects of magnesium on the subjects in these studies—healthy men, women with premenstrual anxiety, and people with a diagnosis of GAD—may not generalize to everyone with anxiety or anxiety-related trouble sleeping. So we’ll have to look to future research to confirm or disconfirm magnesium’s calming effects.
Effects of Magnesium on Insomnia
Magnesium affects systems that promote both wakefulness and sleep, so it might have a relationship to insomnia. Two randomized controlled trials suggest that it may improve the sleep and daytime functioning of older adults. (The rationale for exploring the question with older study participants is that as we age, we’re prone to experience changes in the way our bodies absorb, retain, and utilize nutrients, and changes in circadian rhythms. A magnesium deficiency would more likely show up in older adults.)
- The 46 participants in this 8-week study (ages 60–75) were divided into two groups: one taking 500 mg of magnesium a day and the other taking a placebo. Compared with the placebo takers, the magnesium takers experienced significant increases in total sleep time and sleep efficiency, and significant decreases in the time it took to fall asleep and insomnia severity. Moreover, their levels of melatonin (a sleep-friendly hormone) were up while their levels of cortisol (a stress hormone) were down.
- The 43 participants in this 8-week study (ages 74–82) were also divided into two groups, one taking a food supplement containing magnesium, melatonin, and zinc, and the other, a placebo. Again, compared with participants on the placebo, participants taking the supplement experienced significant increases in total sleep time, sleep quality, and ease of getting to sleep. Their early morning alertness and stamina was also improved.
The results of both studies suggest that magnesium may be an effective sleep aid for older adults. Whether young and middle-aged insomnia sufferers would experience the same benefits remains to be seen.
But if you’re comfortable experimenting with alternative treatments for insomnia, as long as you avoid taking too much, magnesium might be worth trying, especially if you’re older. It has none of the drawbacks associated with other sleep aids. Like other supplements, though, it may need to be taken a few weeks before producing effects.
If you prefer to wait for science to confirm supplementary magnesium’s effects on sleep, you may be waiting a long time. There’s little money to be made on vitamins, minerals, and plant-based supplements—so the research lags. That doesn’t mean magnesium or any other supplement won’t help your sleep. It just means it hasn’t been studied yet.