Magnesium oxide vs magnesium lactate

Magnesium oxide vs magnesium lactate: which is better for energy, muscle cramps, tiredness and fatigue?

Author Miriam Ferrer, PhD Last updated 11th March 2020

  • Ingredients & Nutrition

Magnesium oxide vs magnesium lactate: which is better for energy, muscle cramps, tiredness and fatigue?

Magnesium is needed for millions of biochemical reactions that power the human body. Unfortunately many people are now deficient in this essential mineral. Food supplements have become a popular way to ensure that you can get enough, but some magnesium compounds are more helpful than others. Here we look at which of the forms used in supplements are more effective, and why.

Why is magnesium important?

Magnesium performs a whole range of functions in the body - in fact, it is absolutely essential for life.

This mineral is found in every cell because it is needed to make the molecules that give them the energy they need to work. It also plays an important role in cell division, the process in which your body continually renews itself.

As if that wasn’t enough, magnesium is required for enzymes that power millions of biochemical reactions.

Without enough magnesium, therefore, you will feel more fatigued.

There are a number of common conditions that are explained by a lack of magnesium - by ensuring that you get enough from your diet may help to address them:

  1. Muscle cramps and twitches1
  2. Weakening of the bones2
  3. Cardiovascular issues including high blood pressure, diabetes, atherosclerosis and arrhythmia of the heart345
  4. Psychological problems and behavioural issues including headaches anxiety, confusion, depression and poor sleep.678
  5. Immune health910

You can find out more in our Magnesium Definitive Guide

 Why take a magnesium supplement?

You can obtain Magnesium from foods found in a traditional healthy diet, including whole grains, brown rice and leafy green vegetables such as spinach.11

However, we know that magnesium insufficiency is on the rise, perhaps because of modern diets that do not include many of these foods and the use of some prescription drugs which can deplete magnesium levels as a side effect. It also becomes more difficult for the body to absorb magnesium from food as we get older - with an ageing population we would expect to see a rise in magnesium deficiency and insufficiency.12

As a result of all this, many people are now choosing to take a magnesium supplement to ensure that they are getting enough. According to the Health Food Manufacturer’s Association, 13.4% of people taking supplements are opting for magnesium - a figure which almost doubled between 2016 and 2019.13

What kinds of magnesium are used in supplements?

The active ingredient in a magnesium supplement is always part of a compound:

  • Magnesium oxide
  • Magnesium citrate
  • Magnesium lactate
  • Magnesium malate
  • Magnesium sulfate
  • Magnesium bisglycinate

The kind of molecule to which the magnesium is bound will determine the effectiveness of the supplement.

Which magnesium supplements are best?

For a supplement to take effect, your body needs to absorb the right amount of the active ingredient.

The term we use for this is ‘bioavailability’. It is a measure of how easily your body can absorb a substance.

For example, when you eat a meal the food is taken into your digestive system. Some of the helpful nutrients are absorbed into your bloodstream, but because your body is not perfectly efficient some of them are excreted or destroyed.

If your body can take in a lot of a particular substance, that substance is called bioavailable. Unfortunately, many of the beneficial micronutrients sold as supplements are difficult for the body to absorb, including magnesium.

With the right research it is possible to boost the bioavailability of a supplement to increase its effectiveness. When you choose a highly bioavailable supplement, it is more likely to help you achieve your goals.

One way to increase the bioavailability of a magnesium supplement is to use a compound that makes it easier for your body to absorb.

Many supplements contain magnesium oxide, but we know that magnesium lactate is easier to absorb.141516

Can magnesium lactate prevent side effects from taking magnesium?

Magnesium is safe when taken by mouth in doses under 350mg.

When people take magnesium supplements over a period of time it can cause a few minor but unpleasant side effects such as:

  • Nausea
  • Loose stools or diarrhoea
  • Upset stomach

Fortunately, it is possible to reduce the chances of suffering from these side effects.

Some magnesium compounds, such as magnesium lactate, are more easy-to-absorb. This means that less of the actual magnesium needs to be included in the supplement for it to achieve the desired effect. The likelihood of feeling nauseous or having diarrhoea therefore goes down.


Without enough magnesium, you are more likely to experience a range of unpleasant health problems. Many people are turning to health supplements as a way to ensure they are not deficient, but are unaware that the magnesium compounds found in these supplements may not be as effective or may be more likely to cause side effects.

Magnesium oxide is the most common compound used in supplements, but other compounds such as magnesium lactate are more easy to absorb and therefore make it less likely that you will experience side effects.


  1. Bilbey DL, Prabhakaran VM. Muscle cramps and magnesium deficiency: case reports. Can Fam Physician. 1996 Jul;42:1348-51
  2. Castiglioni S, Cazzaniga A, Albisetti W, Maier JA. Magnesium and osteoporosis: current state of knowledge and future research directions. Nutrients. 2013;5(8):3022–3033. Published 2013 Jul 31. doi:10.3390/nu5083022
  3. Severino P, Netti L, Mariani MV, et al. Prevention of Cardiovascular Disease: Screening for Magnesium Deficiency. Cardiol Res Pract. 2019;2019:4874921. Published 2019 May 2. doi:10.1155/2019/4874921
  4. DiNicolantonio JJ, Liu J, O’Keefe JH, Magnesium for the prevention and treatment of cardiovascular disease. Open Heart 2018;5:e000775. doi: 10.1136/openhrt-2018-000775
  5. Barbagallo M, Dominguez LJ. Magnesium and type 2 diabetes. World J Diabetes. 2015;6(10):1152–1157. doi:10.4239/wjd.v6.i10.1152
  6. Tarleton EK, Littenberg B, MacLean CD, Kennedy AG, Daley C (2017) Role of magnesium supplementation in the treatment of depression: A randomized clinical trial. PLOS ONE 12(6): e0180067.
  7. Eby GA, Eby KL. Rapid recovery from major depression using magnesium treatment. Med Hypotheses. 2006;67(2):362-70. Epub 2006 Mar 20
  8. Kirkland AE, Sarlo GL, Holton KF. The Role of Magnesium in Neurological Disorders. Nutrients. 2018;10(6):730. Published 2018 Jun 6. doi:10.3390/nu10060730
  9. Tam M, Gómez S, González-Gross M, Marcos A. Possible roles of magnesium on the immune system. Eur J Clin Nutr. 2003 Oct;57(10):1193-7
  10. Galland L. Magnesium and immune function: an overview. Magnesium. 1988;7(5-6):290-9
  11. NHS, Vitamins and Minerals: Others. Conditions
  12. Government UK, National Diet and Nutrition Survey. Government; collections.
  13. HTC Health, (2019) HFMA Survey.
  14. Blancquaert L, Vervaet C, Derave W. Predicting and Testing Bioavailability of Magnesium Supplements. Nutrients. 11. 1663. 10.3390/nu11071663
  15. Coudray C, Rambeau M, Feillet-Coudray C, Gueux E, Tressol J, Mazur A, Rayssiguier, Y. Study of magnesium bioavailability from ten organic and inorganic Mg salts in Mg-depleted rats using a stable isotope approach. Magnesium research : official organ of the International Society for the Development of Research on Magnesium. 18. 215-23
  16. Ranade V, Somberg J. Bioavailability and Pharmacokinetics of Magnesium After Administration of Magnesium Salts to Humans. American journal of therapeutics. 8. 345-57. 10.1097/00045391-200109000-00008