Supplements
Magnesium glycinate vs citrate: which one should you take?
By Kim Ingwersen · Published 13 October 2026
Magnesium glycinate and magnesium citrate are the two most popular magnesium supplements, and they are both good choices. The difference is less about how much you absorb and more about how your stomach reacts and what you want the magnesium for. Magnesium is also one of the most common biohacking supplements, so it is worth getting the form right.
The short answer
| Glycinate | Citrate | |
|---|---|---|
| Bound to | Glycine | Citric acid |
| Stomach | Gentle | Can loosen stools |
| Best for | Evening, sleep | Price, constipation |
| Cost | Higher | Lower |
What is magnesium glycinate?
Magnesium glycinate (often sold as bisglycinate) is magnesium bound to the amino acid glycine. It is well absorbed and rarely upsets the stomach, which makes it the usual choice for people who take magnesium in the evening or who get loose stools from other forms.
Glycine has been studied for sleep on its own, at doses of around 3 grams. A typical dose of magnesium glycinate gives about half that, so you get a little glycine as a bonus, not a full dose.
What is magnesium citrate?
Magnesium citrate is magnesium bound to citric acid. It is one of the cheapest well-absorbed forms. In larger doses it draws water into the gut, which is why it is also used as a laxative. For people with a slow stomach that is a plus. For others it is a reason to choose glycinate instead.
Which is absorbed better?
Both are absorbed far better than magnesium oxide, the cheap form found in many tablets. In a 60-day trial with 46 healthy adults, citrate gave the highest magnesium levels in the blood, ahead of an amino acid chelate (the group glycinate belongs to) and oxide (Walker et al., 2003). Oxide was no better than placebo.
The study was small, and the difference between citrate and the chelate was modest. In practice, both are good options, and how your stomach handles them matters more.
Which is better for sleep?
Magnesium is no sleeping pill, but it can help a little. In a 2025 trial, 155 adults who slept poorly took 250 mg of magnesium as bisglycinate or a placebo for four weeks. The magnesium group improved slightly more on the Insomnia Severity Index, and the authors called the effect modest (Schuster et al., 2025).
A review of three small trials in older adults found that magnesium shortened the time it took to fall asleep by about 17 minutes, but the quality of the studies was low (Mah and Pitre, 2021). Light, regular hours and a cool bedroom do more for sleep than any supplement.
There is no trial comparing glycinate and citrate for sleep. Glycinate is the common choice simply because it is easy on the stomach at night.
Which is better for constipation?
Citrate. It pulls water into the bowel and softens the stool. If you want a supplement that also keeps you regular, citrate does both jobs. If loose stools are a problem, choose glycinate.
How much should you take?
Adults need 310–420 mg of magnesium a day in total, depending on age and sex. The US National Institutes of Health sets the upper limit for magnesium from supplements at 350 mg a day for adults, because more can cause diarrhoea (NIH Office of Dietary Supplements). That limit does not include magnesium from food.
Look at the amount of elemental magnesium on the label, not the weight of the whole compound. 2,500 mg of magnesium glycinate contains only about 300 mg of magnesium. Start with 100–200 mg a day, and split larger doses between morning and evening.
Good food sources are nuts, seeds, whole grains, beans, dark chocolate and leafy greens. Many people get close to what they need from food alone.
Who should be careful?
- Kidney disease. The kidneys remove extra magnesium. If they don’t work well, magnesium can build up in the blood. Don’t take supplements without talking to your doctor.
- Medicines. Magnesium can reduce the absorption of some antibiotics (tetracyclines and quinolones), osteoporosis drugs (bisphosphonates) and thyroid medicine. Take them a few hours apart, and ask your pharmacist if you are unsure.
- Diarrhoea. If your stomach is already loose, avoid citrate.
Bottom line
Choose glycinate for the evening and a sensitive stomach, and citrate for a lower price or a slow stomach. Keep the dose moderate, count the elemental magnesium, and don’t expect a supplement to fix sleep on its own.
Sources
- Walker et al. (2003): Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study, Magnesium Research
- Schuster et al. (2025): Magnesium bisglycinate supplementation in healthy adults reporting poor sleep, Nature and Science of Sleep
- Mah and Pitre (2021): Oral magnesium supplementation for insomnia in older adults: a systematic review and meta-analysis, BMC Complementary Medicine and Therapies
- NIH Office of Dietary Supplements: Magnesium fact sheet for health professionals
Frequently asked questions
Is magnesium glycinate or citrate better for sleep?
Glycinate is the usual choice for sleep because it is gentle on the stomach. In a 2025 trial, 250 mg of magnesium as bisglycinate improved insomnia scores slightly more than placebo. There is no head-to-head trial against citrate.
Can I take magnesium glycinate and citrate together?
Yes. Some people take citrate in the morning and glycinate in the evening. Count the total amount of magnesium from both, and stay below 350 mg a day from supplements unless a doctor tells you otherwise.
Does magnesium citrate make you poop?
It can. Citrate draws water into the gut, so higher doses loosen the stool. That is why it is also sold as a laxative. At 200–300 mg a day most people only notice softer stools, if anything.
How much magnesium glycinate should I take?
Start with 100–200 mg of elemental magnesium a day, the amount listed as magnesium on the label, not the weight of the whole compound. Adults need 310–420 mg a day in total, and most of that should come from food.
