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Magnesium Citrate
Magnesium citrate is one of the most popular and easily absorbed magnesium supplements. In this form, magnesium is bound to citric acid (a large molecule), so there is a smaller amount of elemental magnesium per capsule. Because citric acid is a mild laxative, magnesium citrate is an excellent choice for individuals with occasional constipation.

Magnesium citrate is a laxative at high doses, which means it causes stool to retain water, making it softer. As a result, taking this supplement may lead to more bowel movements and makes it easier to pass stool.

Fortunately, you won’t need to change your diet when taking these supplements. Nevertheless, you’ll want to inform your doctor if you have any allergies, prescriptions, medications, or conditions that could affect the magnesium citrate.
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Magnesium Oxide
Magnesium oxide is one of the least absorbed forms. Still, because the oxide molecule is small and compact, it delivers one of the highest percentages of elemental magnesium per dose, making it a practical choice for someone who wants to take as few capsules as possible.

Because it is not as quickly absorbed in the intestine, magnesium oxide has more osmotic (water-attracting) effects in the colon, providing support for those with occasional constipation.

Some people also take it as an antacid to help relieve issues like stomach acid, heartburn, or indigestion. Like magnesium citrate, magnesium oxide at high doses can also work as a laxative to facilitate bowel movements for those going into surgery.
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Magnesium Glycinate
Magnesium glycinate is a gentle form for individuals who are sensitive to magnesium oxide or citrate, as it is less likely to cause a laxative effect. In this form, magnesium is bound to glycine, a non-essential amino acid involved in protein synthesis and transmission of chemical signals in the brain.

Glycine is considered a relaxing neurotransmitter and may enhance magnesium’s natural calming properties. This may be one of the best types for promoting relaxation and good quality sleep. So, if you struggle with mood and stress related challenges, you can take magnesium glycinate to help alleviate the symptoms.

In addition to promoting a positive mental state, this supplement is also great for promoting bone health, maintaining proper heart rhythm, maintaining healthy blood sugar levels, and reducing symptoms of premenstrual syndrome. Some people also use it to reduce pain and enhance physical performance during exercise.

Magnesium glycinate is a great option for people who don’t absorb magnesium well. Unfortunately, this mineral can still cause some stomach upset, which is why it’s recommended you take it with food. Also, you should take note of the amount of magnesium in the supplements you take for your safety.
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Magnesium Malate
Another gentler form of magnesium – for individuals who may be more sensitive to magnesium oxide or citrate – is magnesium malate. It is often recommended for people looking for energy support since malic acid – a natural fruit acid present in most cells in the body – plays a crucial role in ATP synthesis and energy production.

Magnesium malate is absorbed more readily compared to other magnesium supplements. Like other magnesium supplements, magnesium malate can produce a laxative effect, and can provide cranial nerve comfort support related to magnesium deficiency. Magnesium malate may also help to boost your mood.
https://ods.od.nih.gov/factsheets/Magnesium-Consumer/