Magnesium is one of the most popular and accessible dietary supplements available. If you’re thinking about starting magnesium supplements, you may be wondering if you should take magnesium in the morning or at night, or what the potential benefits are. This guide explores how magnesium may improve your health and whether the time you take it impacts its effectiveness.

About magnesium

Magnesium is an essential mineral that plays a crucial role in many bodily functions, including energy production, nerve signalling and maintaining your bone health and muscle function. The NHS recommends your daily magnesium intake should be 270 to 300mg per day, depending on your age and sex. [1]

You can get this from eating a varied and balanced diet containing magnesium-rich foods — green leafy vegetables, whole grains and nuts — but you can also boost your intake by taking dietary supplements.

Some people have a magnesium deficiency, where their body doesn’t have enough magnesium to function. Conditions such as diabetes, chronic diarrhoea and celiac disease can increase your risk of magnesium deficiency.

You may not experience symptoms until your magnesium levels are severely low, but signs of deficiency may include muscle cramps or muscle weakness.

Forms of magnesium

There are many types of magnesium supplements. Here are some popular forms of magnesium, and what they’re typically taken for:

• Magnesium citrate — Increases levels of magnesium in your body and treats constipation. [2] [3]
• Magnesium chloride — Treats low magnesium levels, may be found in creams and lotions for muscle relaxation. [4] [5]
• Magnesium oxide — May help relieve acid reflux, indigestion and constipation. [6]
• Magnesium glycinate — Contains amino acid glycine which is associated with calming effects, so may help treat anxiety, depression and insomnia. [7]
• Magnesium lactate — Used as a food additive to fortify food and beverages.
• Magnesium threonate — May support brain health and help manage health conditions such as Alzheimer’s disease, depression and age-related memory loss. [8]

Benefits of taking magnesium

There are many benefits of magnesium supplements. Magnesium helps support over 600 reactions in your body, including [9]:

• Energy production: Turning food into energy.
• Muscle function: Helping your muscles relax and contract when you move.
• Protein creation: Forming proteins from amino acids.
• Nervous system regulation: Controlling neurotransmitters, the chemicals that help signals travel through your brain and body.

Magnesium may also have other benefits for your general health, but there’s mixed clinical evidence for this. Some studies have shown that supplementing magnesium may help reduce your blood pressure. [10]

One of the most popular reasons for taking magnesium supplements is to achieve restful sleep, and there’s some evidence that higher magnesium intake also helps increase sleep duration. [11]

Magnesium in the morning or at night?

Should you take magnesium in the morning or at night? You can take magnesium supplements at any time of day. The most important thing is consistency — many of the benefits of magnesium supplements are associated with their long-term use.

The optimal time to take magnesium is whenever it works best for you and your routine. Some people find it easier to take supplements first thing in the morning. If you take magnesium at mealtimes, morning or evening, it may help prevent some adverse digestive effects, including diarrhoea and nausea. [12]

You don’t necessarily need to take magnesium before bed if you’re aiming to improve your sleep as it’s your total daily intake that’s linked to restfulness.

You should also be aware of any potential drug interactions with other medications you’re taking. If you’re taking antibiotics, or any other regular medications, speak to your doctor about the best time for your magnesium dose to ensure maximum effectiveness and minimal side effects.

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References:

1. NHS. Vitamins and Minerals [Internet]. NHS. 2020. Available from: https://www.nhs.uk/conditions/vitamins-and-minerals/others/ 

2. Magnesium citrate [Internet]. Available from: https://bnf.nice.org.uk/drugs/magnesium-citrate/#indications-and-dose 

3. Magnesium Citrate, Low Sodium Lemon686.001/686AF [Internet]. Nih.gov. 2022 [cited 2025 Jan 17]. Available from: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=a58a14bf-3e49-4216-a8c8-cee53a620c80 

4. PubChem. Magnesium chloride [Internet]. Nih.gov. PubChem; 2019. Available from: https://pubchem.ncbi.nlm.nih.gov/compound/Magnesium-chloride 

5. Engen DJ, McAllister SJ, Whipple MO, Cha SS, Dion LJ, Vincent A, et al. Effects of transdermal magnesium chloride on quality of life for patients with fibromyalgia: a feasibility study. Journal of integrative medicine [Internet]. 2015 [cited 2020 Jan 12];13(5):306–13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26343101 

6. WebMD Editorial Contributor. Health Benefits of Magnesium Oxide [Internet]. WebMD. 2020 [cited 2025 Jan 17]. Available from: https://www.webmd.com/diet/health-benefits-magnesium-oxide#091e9c5e8205ff00-1-2 

7. Cox RC, Olatunji BO. Sleep in the anxiety-related disorders: A meta-analysis of subjective and objective research. Sleep Medicine Reviews. 2020 Jun;51:101282.

8. Zhang C, Hu Q, Li S, Dai F, Qian W, Hewlings S, et al. A Magtein®, Magnesium L-Threonate, -Based Formula Improves Brain Cognitive Functions in Healthy Chinese Adults. Nutrients. 2022 Dec 8;14(24):5235.

9. de Baaij JHF, Hoenderop JGJ, Bindels RJM. Magnesium in man: implications for health and disease. Physiological reviews [Internet]. 2015;95(1):1–46. Available from: https://www.ncbi.nlm.nih.gov/pubmed/25540137 

10. Banjanin N, Belojevic G. Changes of Blood Pressure and Hemodynamic Parameters after Oral Magnesium Supplementation in Patients with Essential Hypertension—An Intervention Study. Nutrients. 2018 May 8;10(5):581.

11. Zhang Y, Chen C, Lu L, Knutson KL, Carnethon MR, Fly AD, et al. Association of magnesium intake with sleep duration and sleep quality: findings from the CARDIA study. Sleep [Internet]. 2021 Nov 20;45(4):zsab276. Available from: https://pubmed.ncbi.nlm.nih.gov/34883514/ 

12. Magnesium [Internet]. [cited 2025 Jan 17]. Available from: https://www.urmc.rochester.edu/encyclopedia/content?contenttypeid=19&contentid=Magnesium