Does magnesium glycinate make you sleepy?
Ask online which magnesium helps sleep and glycinate wins almost every time. The trials tell a quieter story. Three small studies in older adults, none of them with glycinate, and an evidence rating of low to very low.
contentsWill it make you sleepy?
Key points
- Drowsiness is not a listed side effect of magnesium on the NIH consumer fact sheet.
- Three small trials in older adults found people fell asleep about 17 minutes faster than on placebo.
- Those trials used magnesium oxide and citrate. None used glycinate.
- The evidence was rated low to very low quality.
- Adults should keep supplement magnesium within 350 mg a day, unless a doctor says otherwise.
Will it make you sleepy?
Probably not in the way a sleeping pill does. The NIH’s consumer fact sheet lists diarrhea, nausea and cramping as the effects of too much magnesium from supplements. Drowsiness is not on it, and the fact sheet does not discuss sleep at all.[51]
The question people are really asking is whether it helps them sleep. That is answered by trials, and there are fewer of them than the internet suggests.
What the sleep trials found
A 2021 systematic review found three randomized trials of magnesium for insomnia, covering 151 older adults in three countries.[50]
chart · difference versus placebo, in minutes
Faster to fall asleep. No clear change in total sleep.
Fell asleep faster by
17.4 minSlept longer by (not significant)
16.1 min
Doses ran from 320 to 729 mg a day for 20 days to 8 weeks. The authors rated the evidence low to very low and judged every trial at moderate to high risk of bias.[50] In plain terms, there may be a small benefit for older adults with insomnia, and we cannot be confident of it.
The glycinate question
Here is the twist. The trials in that review used magnesium oxide and magnesium citrate tablets.[50] We found no sleep trial of magnesium glycinate specifically.
The NIH lists aspartate, citrate, lactate and chloride as forms the body absorbs more easily.[51] Glycinate is often recommended because it is said to be gentler on the stomach, and because glycine itself has a small sleep literature. The amount of glycine in a magnesium supplement is far below the 3 grams used in those studies, which tested glycine on its own.[53]
How much is too much
Adults need roughly 310 to 420 mg of magnesium a day from all sources. For supplements and medicines, the NIH sets the adult upper limit at 350 mg a day, separate from food.[51] Magnesium can also interact with some medicines, including certain antibiotics, diuretics and osteoporosis drugs.[51]
Watch for stacking. A magnesium powder in an evening drink, a sleep blend and a multivitamin can add up quickly. Our sleepy girl mocktail check covers one common example.
Food first
Legumes, nuts, seeds, whole grains, leafy greens and milk products all supply magnesium.[51] A diet with plenty of those covers most people. If you think you are low, a doctor can check before you start supplementing.
Fewer supplements. Better questions.
Subscribers get our ingredient reads first, with the dose limits spelled out.
Sources
- Mah & Pitre, 2021. Oral magnesium supplementation for insomnia in older adults: a systematic review and meta-analysis. BMC Complementary Medicine and Therapies.
- NIH ODS, 2021. Magnesium: Fact Sheet for Consumers. NIH Office of Dietary Supplements.
- Bannai et al., 2012. The effects of glycine on subjective daytime performance in partially sleep-restricted healthy volunteers. Frontiers in Neurology.
This article is educational and isn’t medical advice. It was written and checked by the UNWIRE™ editorial team; no clinician has reviewed it yet. UNWIRE™ is a nutrition company, and this article does not describe any product.
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