When Should You Take Magnesium?

Part of our guide: A Beginner's Guide to Vitamins and Supplements

By the BasketLab team · updated 24 July 2026 · how we rank

Evening, with food. If that's all you came for, you can close the tab, because for most people it genuinely is that simple. But the form you've bought changes things a little, and there's a decent reason the evening tends to win, so stick around if you want the why.

The short version

Take it in the evening, with or just after a meal. Magnesium has a mild calming effect for a lot of people, which is why bedtime suits it better than first thing. Taking it with food also softens the main side effect, which is a slightly loose tummy if you get the dose or the form wrong.

That's the answer. Everything below is nuance for people who like knowing the reasons, or who've bought a specific type and want to get the most from it.

The form matters more than the clock

Not all magnesium is the same, and the type on the label tells you a lot:

• Magnesium glycinate is the gentle one. Well absorbed, easy on the stomach, and the one most people reach for if sleep is the goal.
• Magnesium citrate absorbs well too, but it has a laxative lean. Handy if you're a bit blocked up, less handy if you're not.
• Magnesium oxide is the cheap filler you'll spot in a lot of budget tubs. Your body absorbs very little of it, so a big number on the front of the pot can be misleading.

With food, without food, does it matter?

So before you fret about timing, check what you've actually got. A pot from Nutravita or Nutrition Geeks will state the form clearly; if all it says is 'magnesium' with a suspiciously high milligram count, it's probably oxide.

With food is ideal. It's not a hard rule, and taking it on an empty stomach won't harm you, but food smooths out the digestive side of things. If you're using it to wind down, having it with your evening meal or a snack an hour before bed hits the sweet spot. And if you're taking a larger amount, splitting it (half at lunch, half in the evening) is kinder on your gut than the whole lot in one go.

A word before you start

Magnesium is one of the better tolerated supplements, but it isn't for everyone. If you've got kidney problems it can build up in ways it shouldn't, and it can interfere with certain medicines, including some antibiotics and blood pressure tablets. A quick chat with your pharmacist, who can see what else you're taking, is worth the two minutes. This isn't medical advice, just a nudge to check if you're on anything regular.