Magnesium Glycinate vs. Magnesium Citrate: A Science-Based Guide

Magnesium is an essential mineral involved in hundreds of biochemical reactions in the body, from muscle function and nervous system regulation to energy production and regulating blood sugar levels.¹ Consumers often reach for magnesium to support sleep, mood, muscle function, or digestive regularity. However, it can be hard to decipher which form of magnesium is best for what. Two forms commonly found in supplements are magnesium glycinate and magnesium citrate. This blog will break down the differences and similarities between the two and highlight when to take each.

What is Magnesium Glycinate?

Magnesium glycinate (also called magnesium bisglycinate) is a compound of magnesium bound to the amino acid glycine, which by definition means it is chelated. In other words, magnesium glycinate is a “delivery form” of magnesium. The glycine, which is a neurotransmitter that supports relaxation and has antioxidant properties², acts like a carrier, helping magnesium to be absorbed more efficiently into the bloodstream. Magnesium glycinate has one glycine; magnesium bisglycinate has two. Being chelated usually represents better absorption properties, making it a popular form for people who want to improve their magnesium levels without causing digestive discomfort issues, such as loose stools, which can be a known side effect of other forms of magnesium, such as magnesium oxide.

Key features of magnesium glycinate:

• Uses: Commonly taken for stress relief, better sleep, as well as for muscle relaxation, including menstrual cramps. Because glycine has calming effects and magnesium plays a role in nerve and muscle function, magnesium glycinate is often used to promote relaxation. It is often taken in the evening when relaxation or sleep support is the goal (a rationale supported by glycine's bedtime data).³
• Tolerability: Magnesium glycinate is known as a “gentle” form of magnesium. It is less likely to cause digestive upset or loose stools compared to some other forms. The glycine component may help carry magnesium through the intestinal wall, and this chelated form doesn’t draw as much water into the intestines as magnesium salts like citrate do, which may lead to less digestive upset.
• Absorption: Magnesium glycinate is very well absorbed and is generally considered to have high bioavailability, meaning a large fraction of the dose gets into the bloodstream.⁴

What is Magnesium Citrate?

Magnesium citrate is a magnesium salt bound to citric acid.⁵ Citric acid is a natural organic acid found in citrus fruits and is a key player in energy metabolism.⁶ Magnesium citrate is highly water-soluble, which contributes to its good absorption in the gut. This form has been used for a long time and is also available in over-the-counter preparations for occasional constipation relief.

Key features of magnesium citrate:

• Uses: Commonly used to relieve constipation, migraines, and leg cramps.^4,7 Magnesium citrate acts as an osmotic laxative – it pulls water into the intestines, softening stool and stimulating bowel movements. It’s actually an active ingredient in some laxative products because of this effect.
• Tolerability: Because it draws water into the gut, magnesium citrate can cause gastrointestinal side effects in some people. The most common are diarrhea, stomach rumbling, and cramps if the dose is too high.⁸ These laxative side effects are sometimes mild at lower doses (which can actually help someone who is mildly constipated stay regular), but at high doses they can lead to dehydration or electrolyte imbalances. Thus, magnesium citrate is very effective for bowel movements, but not as “gentle” as glycinate for people who don’t need the laxative effect.
• Absorption: Magnesium citrate is also considered to have high bioavailability. Because it dissolves easily, it is absorbed efficiently in the intestine. Like glycinate, magnesium citrate is an organic form, and both are among the more absorbable options of magnesium supplements.

When to Take Magnesium Glycinate vs Magnesium Citrate

Timing can play a role in getting the most benefit from a supplement. So, when should you take magnesium glycinate or magnesium citrate? The answer depends largely on your goals and how each form behaves in the body:

• Magnesium Glycinate – Best Taken in the Evening (for Relaxation/Sleep): Magnesium glycinate is often recommended before bedtime if you are using it to help with sleep or nighttime relaxation. In fact, if sleep support is your priority, taking magnesium glycinate about an hour before bedtime is ideal, as it helps calm the nervous system for better sleep.⁹
• Magnesium Citrate – Timing Around Meals and Bowel Movements: Magnesium citrate, especially if taken for constipation or digestive reasons, is often taken earlier in the day. This is to avoid waking up at night with an urgent need for the bathroom. Since magnesium citrate can produce a bowel movement anywhere from 30 minutes to 6 hours after you take it, consider your schedule.⁸ If you’re using magnesium citrate just as a supplement (not laxative) and you notice it loosens your stool, try taking smaller doses spread out, or take it with food to slow its gut transit.

Can You Take Magnesium Glycinate and Citrate Together?

You might wonder if it’s okay to use both forms of magnesium – either at the same time or on the same day. The simple answer is: Yes, you can take magnesium glycinate and magnesium citrate together. Some things to consider:

• Safety of combining: There is no adverse chemical interaction between magnesium glycinate and citrate – they are just two different vehicles for magnesium. In fact, some broad-spectrum magnesium supplements or “magnesium complexes” on the market intentionally combine multiple forms (e.g., citrate, glycinate, malate, etc.) in one capsule or powder.
• Dose Considerations: It’s important to consider total magnesium when combining multiple forms. Magnesium is very safe at recommended levels, but too high a dose at once can cause diarrhea accompanied by nausea and abdominal cramping.¹⁰ The adult upper limit (UL) for supplemental magnesium is 350mg/day unless a clinician directs otherwise.¹
• Staggering vs. Simultaneous: If you want to use both forms for different benefits, one strategy is to stagger their timing. For example, you could take magnesium citrate in the morning or afternoon (to aid digestion and bowel regularity) and magnesium glycinate in the evening (to support sleep). This way you’re not ingesting a large load of magnesium all at once, and you match the timing to the desired effect.
• Medical Considerations: Because magnesium is renally cleared, people with impaired kidney function should not combine (or even start) magnesium supplements without medical guidance due to the risk of hypermagnesemia.