A listener asked me if it is advisable to choose a supplement containing several types of magnesium, instead of a supplement containing only one form. On some products it is written that they combine citrate, glycinate, oxide and sometimes additional types, so it is easy to think that the blend is necessarily more comprehensive and better absorbed. But there is no proof that a supplement containing several types is superior simply due to the combination. What is more important is how much elemental magnesium, meaning net magnesium, is in a serving, which form it contains, whether it is tolerated in the digestive system, and what the reason is for taking the supplement in the first place.
Why is magnesium important?
Magnesium participates in more than 300 enzymatic systems in the body. It is required for muscle and nerve function, energy production, protein and bone synthesis, blood sugar regulation and maintaining a normal heart rhythm. Most magnesium is found in bones and soft tissues, and less than one percent is found in the blood. A significant deficiency may cause weakness, tremors, cramps, heart rhythm disturbances and changes in potassium or calcium levels. However, fatigue, sleep disturbances, headaches or leg cramps are very common phenomena, and do not prove in themselves that magnesium is lacking. Regarding night cramps as well, it is important to be precise: Magnesium is sometimes marketed as an almost certain solution, but a review of randomized trials found no clear benefit for night cramps in the general population. It is possible that there is a smaller effect in certain situations, but muscle cramping is not a diagnosis of magnesium deficiency.
Is a blood test sufficient?
A magnesium blood test can identify a clear deficiency, so it is certainly useful. The limitation is that the level of magnesium in the blood is maintained within a narrow range, while most of it is inside the cells and tissues. Therefore, a normal result does not always rule out low intake or suboptimal stores. Assessment of the situation is made according to a combination of diet, underlying diseases, medications, symptoms and tests. The risk of deficiency rises, among other things, in absorption disorders, prolonged diarrhea, unbalanced diabetes, prolonged use of certain medications, and kidney or gastrointestinal diseases.
How much magnesium is needed per day?
The recommended daily intake for adults is:
Women: 310 to 320 mg.
Men: 400 to 420 mg.
Pregnant women: 350 to 360 mg.
These quantities include magnesium coming from all sources, and mainly from food. The upper limit established for magnesium from supplements and medications is 350 mg a day for adults, unless given otherwise by medical instruction. The limit does not include natural magnesium from food. Therefore, it is incorrect to recommend that anyone who suspects a deficiency automatically start with 400 mg. The dosage must take into account the amount of elemental magnesium in the supplement, diet, the purpose of use and kidney condition. Too high a dosage may cause diarrhea, nausea and abdominal pain. In people with reduced kidney function, there is also a risk of dangerous accumulation of magnesium.
First of all, food – Magnesium is mainly found in: Almonds, nuts, seeds, legumes, oatmeal, quinoa, whole grains, green vegetables, avocado, cocoa, dark chocolate and certain dairy products. There is no reason to ignore food tables. Magnesium content indeed varies according to the type of food, soil and growing methods, but the tables still give a useful estimate. In Israel there is an additional question related to desalinated water, which contains almost no magnesium. Israeli studies raised the possibility that the supply of desalinated water reduces the contribution of drinking water to magnesium intake. However, this does not mean that every person in Israel needs a supplement, nor that all vegetables grown with desalinated water lost their magnesium.
Is a combination of several types absorbed better?
There is currently no good basis to determine that a mix of three or five types of magnesium is absorbed better than a high-quality supplement containing one type. Sometimes several forms are mixed to create a unique marketing product, and sometimes to combine a cheap form with more expensive forms. The most important labeling is the amount of elemental magnesium per serving. A product can boast a large amount of "magnesium citrate", but only a portion of the compound's weight is magnesium itself. The amount that appears in the supplement's table as magnesium is the one that needs to be checked. A combined supplement can be good, but not because it is combined. If most of the magnesium in it comes from oxide and only tiny amounts from other forms, the impressive headline does not tell much.
The differences between the forms
Magnesium oxide: Contains a high percentage of elemental magnesium, but its solubility and absorption are relatively low. It may draw water into the intestines and also serve as a laxative.
Magnesium citrate: More soluble and better absorbed than oxide in small studies. It may also soften stools, especially at high doses.
Magnesium lactate and chloride: Considered soluble forms that are relatively well absorbed.
Magnesium glycinate: Marketed as a gentle form for the digestive system, but the body of direct studies comparing it to other forms is more limited than implied by advertising. There is no basis to say that it is always the best or that it treats sleep and anxiety in everyone.
Higher absorption does not necessarily guarantee a better health outcome.
Powder, liquid or capsule?
Capsules and tablets: Convenient and allow clear dosage, but are sometimes large and hard to swallow.
Powder: Convenient for those who find it hard to swallow and allows changing the amount gradually.
Liquid: Easy to swallow, but sometimes its taste is strong and the exact amount depends on measurement.
Gummies: Convenient, but sometimes contain less magnesium and added sugar.
Spray or oil for the skin: There is currently no good evidence that topical application on the skin significantly raises magnesium stores in the body.
There is no proof that powder or liquid "absorbs faster" just because of the delivery method. What affects it more is the chemical compound, dosage and its solubility.
When do you know if the supplement is suitable?
Diarrhea or abdominal pain can appear early in use, but it is impossible to determine within a day or two whether magnesium stores have improved or whether the supplement is truly beneficial for sleep, muscles or fatigue. Such an effect, if present, usually requires longer follow-up, and even then one must ask if there was a deficiency to begin with. If the supplement causes diarrhea, it is possible that the dosage is too high or the form is unsuitable. In such a case, there is no advantage in continuing to suffer out of the thought that diarrhea proves the supplement "works".
The bottom line
A supplement containing several types of magnesium is not necessarily better than a supplement containing one type. Choose according to the amount of elemental magnesium, the purpose of taking it, digestive tolerance and health condition. For those suffering from constipation, citrate or oxide may also provide a laxative effect. For those with a sensitive digestive system, another form or a smaller dosage can be tried. But there is no single type suitable for everyone, and there is no need to pay more just because a long list of compounds appears on the package.
For Dr. Maya Rosman's YouTube channel: With all the tip videos – click here