Last updated: October 2026
The best time to take magnesium depends on why you take it. For sleep or winding down, take it 30 to 60 minutes before bed. For tiredness or general top-up, any time you will remember works. Taking it consistently every day matters more than the exact hour, and taking it with food helps if it upsets your stomach.
This guide covers the best time by goal and by type (glycinate, citrate, threonate and more), morning vs night, with or without food, and which supplements and medicines to keep apart.
Does the time you take magnesium matter?
Less than most people think. Your body absorbs magnesium whenever you take it, and most of what you don’t use is cleared by your kidneys within a day or two. What builds up your levels is taking it regularly, so the best time is usually the one you can stick to.
Timing does matter in a few situations: when you take magnesium for sleep, when a form has a laxative effect, and when you also take certain medicines. Read more in how long magnesium stays in your body.
Morning vs night: which is better?
| Morning | Evening | |
|---|---|---|
| Best for | Tiredness, general top-up, daytime focus | Sleep, winding down, night-time cramps |
| Easy to remember? | Yes, with breakfast | Yes, as part of a bedtime routine |
| Watch out for | Laxative forms before a commute | Feeling groggy (rare); move earlier if so |
If you are unsure, the evening is a good default for most people, because magnesium fits naturally into a wind-down routine. If you take a larger amount, you can also split it between morning and evening.
Best time to take magnesium by goal
For sleep
30 to 60 minutes before bed. That gives it time to absorb and turns it into a cue that the day is over. A warm magnesium drink works well here. See our full guide to magnesium for sleep.
For stress and anxious feelings
Either split it between morning and evening, or take it in the evening if stress keeps you awake. Magnesium contributes to the normal functioning of the nervous system and normal psychological function. Read more in magnesium for anxiety.
For tiredness and energy
Any time, often in the morning with breakfast. Magnesium contributes to the reduction of tiredness and fatigue and to normal energy-yielding metabolism.
For muscle cramps, restless legs and exercise
Evening is popular for night-time cramps and restless legs. Active people often take it after training or in the evening. See magnesium for restless legs.
For constipation
Magnesium citrate or oxide in the evening can lead to a bowel movement the next morning. Avoid taking a laxative form just before a long journey. See magnesium for constipation and magnesium for bloating.
For PMS
Take it daily across your whole cycle, not just when symptoms start. In a University of Reading trial, the benefit appeared in the second month. See magnesium for PMS.
Best time to take each type of magnesium
| Type | Best time | Why |
|---|---|---|
| Glycinate / bisglycinate | Evening | Gentle on the gut and popular for sleep |
| Citrate | Evening, or when you are near a toilet | Mild laxative effect |
| L-threonate | Morning or early afternoon, or evening if taken for sleep | Usually taken for focus and memory |
| Malate | Morning | Often used in daytime routines |
| Oxide | Evening, with food | Poorly absorbed and can loosen stools |
| Blends and complexes | Follow the label | Depends on the mix of forms and other ingredients |
When to take magnesium glycinate: most people take it 30 to 60 minutes before bed. Our magnesium glycinate guide covers it in detail, and there is more on threonate in our magnesium L-threonate guide.
Our Magnesium Glycinate Sleep Complex combines bisglycinate and citrate and is designed to be taken about 30 minutes before bed.
Should you take magnesium with food or on an empty stomach?
Either is fine for most people. Taking magnesium with food makes stomach upset and loose stools less likely, especially with citrate or oxide. Glycinate is gentle enough that many people take it on an empty stomach before bed. If one way bothers you, switch to the other.
Taking magnesium with other supplements and medicines
Supplements
- Vitamin D: fine to take together. Many people take both through the autumn and winter.
- Calcium, zinc and iron: high doses can compete with magnesium for absorption, so it helps to take large doses of these at a different time of day.
- CBD: magnesium and CBD are often taken together in an evening routine.
Medicines
Magnesium can reduce how well some medicines are absorbed, including certain antibiotics (such as tetracyclines and quinolones), osteoporosis medicines (bisphosphonates) and thyroid medicine (levothyroxine). These usually need to be taken a few hours apart from magnesium. Ask your pharmacist for the right gap for your medicine.
Should you take magnesium every day?
Yes, for most people daily is best, because your body does not store extra magnesium for long. The NHS says adults need 300mg (men) or 270mg (women) a day, mostly from food, and that 400mg or less a day from supplements is unlikely to cause harm. Most people notice a difference after two to four weeks of daily use. See how long magnesium takes to work.
When not to take magnesium
- at the same time as the medicines listed above
- if you have kidney disease, unless your doctor agrees
- a laxative form just before travelling or a long meeting
- above 400mg a day from supplements without medical advice
- if it gives you diarrhoea: lower the dose or switch to glycinate
Black Friday, 27 to 30 November: see our Black Friday magnesium and supplement deals.
FAQs
Is it better to take magnesium in the morning or at night?
Night is best if you take it for sleep, winding down or night-time cramps. Morning suits tiredness or a general top-up. Taking it every day matters more than the exact time.
When is the best time to take magnesium glycinate?
Most people take magnesium glycinate 30 to 60 minutes before bed, because it is gentle on the stomach and fits a wind-down routine.
When should I take magnesium citrate?
In the evening, or when you are near a toilet, because citrate has a mild laxative effect. Take it with food if it upsets your stomach.
Should I take magnesium with food?
Taking it with food helps if it upsets your stomach, especially citrate or oxide. Glycinate is gentle enough that many people take it on an empty stomach.
Can I take magnesium and vitamin D together?
Yes, they can be taken together, and many people take both during the autumn and winter months.
Can I take magnesium every day?
Yes. Most healthy adults can take it daily within the NHS guide of 400mg or less a day from supplements. Check with your GP if you have kidney problems.
Does timing affect magnesium absorption?
Only a little. Taking it consistently matters more. The main timing rules are to keep it apart from certain medicines and to avoid large doses of calcium, zinc or iron at the same time.
How long before magnesium starts working?
Some people feel calmer within days, but most notice a difference after two to four weeks of daily use.
Sources
- NHS. Vitamins and minerals: magnesium.
- NHS. Vitamin D.
- Walker AF et al (1998). Magnesium supplementation alleviates premenstrual symptoms of fluid retention. Journal of Women’s Health.
This guide is general information, not medical advice.
