Magnesium for sleep — which form, what dose, when to take it
If you've been told "magnesium helps you sleep" and stocked up on a generic supermarket bottle, you've probably noticed it doesn't do much. The form matters. The dose matters. The timing matters. Here's what the trial data actually says.
Why magnesium helps sleep at all
Magnesium is a cofactor in over 300 enzyme reactions, but the sleep connection runs through three specific mechanisms: it binds to GABA receptors (the same family of receptors benzodiazepines target, but gently), it regulates melatonin synthesis, and it reduces nighttime cortisol. Deficient adults — and roughly 50% of South Africans don't hit the 320–420mg RDA from food — tend to wake more often, sleep more lightly, and report less restorative sleep.
The form question — glycinate vs citrate vs oxide
Magnesium glycinate is the sleep form. The glycine carrier itself is calming, the magnesium absorbs at around 80% bioavailability, and there's no GI distress. Studies in older adults at 320mg/night showed significant improvements in sleep onset latency, total sleep time, and serum melatonin.
Magnesium citrate is a daily form for general supplementation but also a mild laxative — fine for daytime, bad for sleep if you take it too close to bed.
Magnesium oxide is what's in cheap supermarket multivitamins. 4% absorbed. Skip it.
Magnesium threonate is sometimes marketed as crossing the blood-brain barrier better — the evidence is preliminary and mostly from mouse studies. Doesn't justify the 5x price tag yet.
How much, when
The clinical sleep dose is 200–400mg of elemental magnesium, taken 60–90 minutes before bed. Lower end if you're under 60kg or magnesium-sensitive; higher end if you're heavier or doing intense exercise (which depletes magnesium in sweat).
Take it with a small amount of food if you find it uncomfortable on an empty stomach, but it's not strictly necessary.
What we put in Vivid Tranquil
Vivid Tranquil is our calm-and-sleep formulation. It pairs 300mg of magnesium glycinate with passion flower, valerian, and L-theanine — the four ingredients with the strongest sleep trial data, at doses that match the studies. Not a sledgehammer. Calm without sedation.
When magnesium alone isn't enough
If you've been taking 300mg of glycinate for 4 weeks and your sleep hasn't shifted, the issue probably isn't magnesium deficiency. Common culprits: undiagnosed sleep apnoea, elevated evening cortisol, alcohol within 3 hours of bed, screen exposure past 21:00, or a too-warm bedroom (>19°C). A naturopath consultation can help triage — book a free 15-minute call.