Table of contents
Magnesium intake from the diet is usually below the daily intake recommendation and a large part of the population is magnesium deficient. Magnesium deficiency can cause various symptoms and imbalances in the body. In this article you will find detailed information on the best form of magnesium, the required dosage and the appropriate method of use.
What is magnesium?
Magnesium is an essential mineral that has several important functions, such as promoting the normal functioning of the muscles and nervous system, as well as helping communication between cells, bone formation and metabolism. Magnesium also contributes to maintaining the body’s salt balance and enzyme activity. (1)
Magnesium deficiency
Magnesium deficiency, or hypomagnesemia, is common today. Stress depletes the body’s magnesium reserves, and a lack of magnesium may affect the quality of sleep.
Poor diet and stress can increase magnesium deficiency. According to a 2009 study, today’s vegetables and fruits contain less magnesium than just a few years ago. According to the study, the change is due to the development of different technologies related to agriculture. Faster growing plants no longer have time to store nutrients in fruits and edible parts in the same way as slower growing plants. (2)
Often the fruit is harvested raw and ripened during the journey, which can significantly affect its nutritional content. Although magnesium is naturally present in salt, almost always the magnesium that is important for the body has been removed from the salt used.
In Finland, the official intake recommendation for magnesium is 350 milligrams for men and 280 milligrams for women per day. By comparison, the intake recommendation in the United States is significantly higher (420 mg/day), although Americans are hardly as different from Finns as Finns are. (3)
It is also interesting that the intake recommendations for several other essential nutrients are lower in Finland than in other countries, such as vitamin D, even though the sun shines significantly less in Finland than, for example, in California.
Symptoms of magnesium deficiency:
Symptoms related to magnesium deficiency manifest themselves in different ways.
- Muscle cramps
- Difficulty falling asleep
- Sleep is light or interrupted
- Restlessness
- Anxiety
- Irritation
- Low blood pressure
- Alakuloa
- Impairment of muscle growth
- Restless legs
- Arrhythmias
- High cortisol
- Fatigue
- A feeling of powerlessness
- Slowing down of nail growth
- Impairment of muscle recovery. (3)
Magnesium overdose
Magnesium overdose is rare and it is actually very difficult to get it at least directly from food or through oral preparations. The exception is elderly people with kidney failure, for whom magnesium supplements may increase the blood concentration of magnesium. (4)

There are big differences in products containing magnesium! Good quality magnesium is absorbed quickly. Cheap and low-quality magnesium mainly causes stomach problems.
How do the different forms of magnesium differ from each other?
The different forms of magnesium have big differences. Others are well-absorbed, stomach-friendly and effective, while some magnesium preparations are more laxative and poorly absorbed forms that cause stomach problems.
Magnesium Citrate
Magnesium citrate, which is sold in almost all grocery stores, may cause stomach symptoms in some people, even if the dosage is small (3). Magnesium in citrate form is also not as effective an option for promoting sleep as, for example, glycinate and L-threonate.
Magnesium malate
Magnesium malate participates in the body’s energy production. You should be careful with the timing of dosing, as magnesium containing malate can affect sleep. Malate should be dosed in the morning or during the day, if you are not sure how it will affect you. (3)
Magnesium oxide
Magnesium oxide is a poorly absorbed, although very common, form of magnesium. Magnesium containing oxide irritates the stomach and acts as an effective laxative. According to several experts, you should avoid consuming magnesium oxide and choose a more absorbable and stomach-friendly form of magnesium. (3)
Magnesium glycinate / bisglycinate
Magnesium glycinate (or bisglycinate) is one of the best forms of magnesium and is also suitable for sensitive stomachs. So glycinate does not irritate the stomach, and does not cause diarrhea like some forms of magnesium do.
In addition to its official health claims, magnesium bisglycinate has been shown to have several other notable ones including:
- Relieves anxiety
- Promotes bone health
- Control blood sugar in people with diabetes and may reduce the risk of developing type 2 diabetes
- Maintains a normal heart rhythm
- Reduces symptoms of premenstrual syndrome (PMS).
- Enhances exercise performance
- It can also help reduce pain (5)
On several pages that go over magnesium the best forms often emphasize magnesium glycinate and its effectively absorbed properties such as excellent absorption and stomach-friendly effects. Magnesium preparations containing glycinate are also sold under the name magnesium bisglycinate, which means the same thing. Sometimes we also talk about chelated magnesium glycinate.
Magnesium glycinate is also used to treat certain conditions, including:
- Fibromyalgia ( Rheumatology International study)
- Chronic fatigue syndrome ( BMC Complementary and Alternative Medicine )
- Heart failure, stroke, diabetes ( BMC Medicine ).
Magnesium L-threonate
Magnesium L-threonate is the only form of magnesium that crosses the blood-brain barrier and rapidly increases the amount of magnesium in the brain and spinal fluid. (6).
According to a study published in 2016, administration of magnesium L-threonate to patients aged 50-70 with mild cognitive decline produced significant changes without significant side effects. The test period was 12 weeks. (7)
TEST RESULTS WITH MAGNESIUM L-THREONATE
- Magnesium levels increased in the body and brain.
- The average age of the brain decreased by up to 9 years.
- The deterioration of cognitive abilities was significantly reduced.
- Task performance, attention to things, memory and episodic memory improved. (7)
Other forms of magnesium
Other forms of magnesium include e.g. marine magnesium i.e. magnesium hydroxide, magnesium taurate, magnesium chloride and magnesium glycerophosphate.
Use of magnesium
Magnesium is usually dosed once or twice a day. A general recommendation is to take magnesium in the evening before going to bed, as it can also help you relax and improve the quality of your sleep. Magnesium can be taken with a meal, which can reduce possible stomach problems caused by magnesium, such as heartburn (3).
Note! Magnesium should not be consumed at the same time as iron, because magnesium may interfere with the absorption of iron. If you have an iron deficiency in your body and you are using an iron supplement, you should preferably schedule the administration of magnesium at least a couple of hours at a different time than the iron. (3)
Intake recommendation and dosage
The dosage of magnesium is affected by age, gender and prevailing life situation. In general, the amount recommended for intake increases with age, and a higher dosage is recommended for older men than for women. During pregnancy, the need for magnesium increases slightly. After the pregnancy period, the intake recommendation returns to normal even when breastfeeding. (8)

Magnesium intake recommendation according to age and gender.
The benefits of magnesium
The body needs magnesium for more than 300 different events related to the body’s metabolism. In addition, magnesium participates in the production of cellular energy. It is needed for muscles, nervous system and bones. By promoting normal energy metabolism, magnesium can also help reduce exhaustion and fatigue. (9)
Magnesium promotes normal muscle function by influencing the regulation of muscle contraction. Classified as an electrolyte, magnesium also affects how impulses travel in the nervous system. Adequate intake can also promote psychological functions. In addition, its role in dental health is also scientifically important. (9)
Approved health claims for magnesium
- Helps reduce fatigue and exhaustion
- Promotes normal muscle function
- Promotes the normal functioning of the nervous system
- Promotes the maintenance of normal bones
- Promotes normal energy metabolism
- Promotes normal psychological functions
- Promotes electrolyte balance
- Promotes normal protein synthesis
- Participates in the process of cell division
- Promotes normal teeth. (9)
Adverse effects of magnesium
Magnesium can also have side effects. Low-quality and cheap forms of magnesium, such as magnesium oxide, may cause stomach upset and laxative effects without significantly increasing the amount of magnesium in the body.
Some forms of magnesium are such that the body may take a while to get used to them. That’s why you should start with a smaller amount and increase the dose slowly. The best way to find out by experimenting is if some magnesium, for example, prevents you from sleeping at night or causes stomach problems. It is very rare to get too much magnesium, so the risk of overdose is unlikely. (9)

The best food sources of magnesium are seeds, nuts, vegetables and grains.
Foods containing magnesium
In terms of optimal health, the role of magnesium is significant. Magnesium can also be obtained naturally from food such as seeds, nuts, vegetables and grains. Hemp seeds are one of the best sources of magnesium.
It is not very easy to get magnesium from a grain-free diet, and therefore a separate magnesium preparation is recommended to support the diet, especially for celiacs. Gluten-free options, e.g. oats and quinoa contain magnesium. (9)
Experiences with the effects of magnesium
According to experience and some tests, people also get help from magnesium for ailments that have not yet been done or replicated with sufficient accuracy in standardized studies. Such symptoms include e.g. cramps and varicose veins in the limbs. Magnesium is also used a lot for post-exercise recovery and muscle relaxation, which are not yet listed as official health benefits.
Magnesium reference values
With the help of a blood test, the concentration of magnesium in the body can be examined. The reference value for magnesium is 0.71-0.94 mmol/l. (10)
A value below the reference value is often related to some kind of magnesium absorption disorder or, alternatively, it can be related to kidney function. Magnesium deficiency can also be caused by a one-sided diet that does not contain enough magnesium-rich foods. (10)
Certain medications, diseases and symptoms can also reduce the amount of magnesium in the body. These include, for example, laxatives, diarrhea, vomiting, anorexia, bulimia and celiac disease. (10)
Combined effect
Magnesium and L-theanine have synergistic effects.
Consuming alcohol and theanine at the same time is not recommended because it can cause dizziness, slowing of motor reflexes and in some cases nausea.
Neuroscientist Andrew Huberman recommends taking magnesium and L-theanine at the same time about half an hour to an hour before going to bed (11).
Summary
Magnesium is a generally safe and much-studied mineral and dietary supplement, with big differences in different forms. The best and well-absorbed forms of magnesium are e.g. magnesium L-threonate and magnesium bisglycinate. The above-mentioned magnesium preparations do not often cause stomach symptoms and are absorbed more efficiently than many other preparations. Magnesium oxide is not recommended for increasing magnesium levels.
Sources
- K. Englund. 2021. Magnesium contributes to the normal functioning of the body. https://www.terveystalo.com/fi/tietopaketit/magnesium. Referenced 02/20/2023.
- Davis, DR 2009. HortScience. Declining Fruit and Vegetable Nutrient Composition: What Is the Evidence? https://doi.org/10.21273/HORTSCI.44.1.15. Referred on 02/09/2023
- Kaisa Jaakkola. 2020. Magnesium and testing its need. https://www.kaisajaakkola.com/2013/09/magnesium/. Referenced 02/20/2023
- Health library. Magnesium. https://www.terveyskirjasto.fi/dlk00818
- healthline.com. 2022. Magnesium Glycinate. Everything You Should Know About Magnesium Glycinate. Referenced 02/20/2023
- O. Sovijärvi. Biohacker shop. Optimizing Deep Sleep and Biohacking: A Comprehensive Review of Improving Sleep Quality and Deep Sleep. Referenced 02/28/2023
- Guosong, L et al.. 2016. Efficacy and Safety of MMFS-01, a Synapse Density Enhancer, for Treating Cognitive Impairment in Older Adults: A Randomized, Double-Blind, Placebo-Controlled Trial. https://pubmed.ncbi.nlm.nih.gov/26519439/. Referred on 02/09/2023
- National Institutes of Health. 2022. Office of Dietary Supplements—Magnesium. https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/. Referenced 02/03/2023
- Self-care pharmacy. 2020. Vitamin and trace elements. The body needs magnesium. https://www.itsehoitoapteekki.fi/artikkelit/vitaminit-ja-hivenaineet/elimisto-tarvitsee-magnesiumia/. Referred to 31.01.2023
- Zip. 2022. Magnesium – Benefits, Sources, Recommendation, Measurement and Deficiency . https://www.puhti.fi/tietopaketit/magnesium/. Referenced 02/20/2023
- Huberman A. 2021. Hubermanlab.com. Toolkit for sleep . https://hubermanlab.com/toolkit-for-sleep/. Referred to 31.01.2023