Magnesium Glycinate vs Citrate: What's the Difference?
Magnesium glycinate is magnesium bound to glycine, an amino acid. Magnesium citrate is magnesium bound to citric acid. Both supply the same mineral. The main practical difference is that citrate is also sold in larger amounts as a saline laxative. For either form, the number that matters most is the elemental magnesium on the label.
Same mineral, different partner
Magnesium in a capsule or powder is always attached to something else. That partner gives the form its name. In magnesium glycinate, the partner is glycine. In magnesium citrate, it is citric acid. Other forms you may see include oxide, chloride, lactate and aspartate.
Your body uses the magnesium itself. The partner mainly affects how well the compound dissolves, how much magnesium it carries, and how it feels in your stomach.
Elemental magnesium: the number to check
Labels can list two different weights. One is the weight of the whole compound. The other is the elemental magnesium, which is the actual mineral you get. For example, NuvaMag uses 2,500 mg of magnesium glycinate to provide 275 mg of elemental magnesium per serving. When you compare products, always compare the elemental amount.
What the NIH says about absorption
The NIH Office of Dietary Supplements (ODS) explains that forms of magnesium that dissolve well in liquid are absorbed better than other forms. It says the aspartate, citrate, lactate and chloride forms tend to have higher bioavailability than magnesium oxide and magnesium sulfate.
The ODS fact sheet does not discuss magnesium glycinate. So there is no NIH comparison of glycinate and citrate to point to, and we do not claim that one is proven to be absorbed better than the other.
Magnesium citrate as a laxative
Magnesium citrate has a second life as an over-the-counter medicine. MedlinePlus describes it as a saline laxative used on a short-term basis for occasional constipation. It works by drawing water into the stool. MedlinePlus says it usually causes a bowel movement within 30 minutes to 6 hours, and that you should not take it for more than a week unless your doctor tells you to.
Those laxative products contain much more magnesium than a daily nutrition product. Small amounts of magnesium citrate also show up in many drink mixes, where they add a little magnesium to your water.
What about stomach comfort?
The ODS says high intakes of magnesium from nutrition products and medicines can cause diarrhea, nausea and stomach cramps. The forms most often reported to cause diarrhea are magnesium carbonate, chloride, gluconate and oxide.
Glycinate is not on that list, but the ODS fact sheet does not cover glycinate at all. The safest approach for any form is the same: take the amount on the label, with water, and stay within the upper limit.
Side by side
| Magnesium glycinate | Magnesium citrate | |
|---|---|---|
| Bound to | Glycine, an amino acid | Citric acid |
| NIH note on absorption | Not covered by the ODS fact sheet | Listed among forms with higher bioavailability |
| Also sold as | Daily nutrition capsules and powders | A saline laxative for occasional constipation |
| What to check | Elemental magnesium per serving | Elemental magnesium per serving, and whether it is a laxative product |
How to choose
- For a daily habit, pick a product meant for daily use, not a laxative, and check the elemental magnesium.
- Count your total. Adults should not get more than 350 mg a day of magnesium from nutrition products and medicines, unless a doctor advises it. Magnesium from food does not count toward this limit.
- Look at the serving. Some products need several capsules to reach the amount on the front of the label.
- Pick a time you will remember. Our guide on the best time to take magnesium covers morning and evening options.
Food comes first
Most of your magnesium can come from food. The NIH says adult men need 400 to 420 mg a day and adult women need 310 to 320 mg, from food and nutrition products combined. Legumes, nuts, seeds, whole grains and leafy greens such as spinach are good sources. A product can fill the gap on days when your plate falls short.
How NuvaMag fits
NuvaMag uses magnesium glycinate. Each three-capsule serving provides 275 mg of elemental magnesium from 2,500 mg of magnesium glycinate. It has no melatonin, so you can take it at any time of day. Take three capsules once a day with water. It is part of our Calm collection.
Our HydraZen and EnerZen drink mixes use magnesium citrate in small amounts: 20 mg per scoop of HydraZen and 36 mg per serving of EnerZen. If you use them with NuvaMag, add up the magnesium so your total stays within the 350 mg limit. Nuvazen products are made in FDA-registered, GMP-compliant facilities, with a Certificate of Analysis (COA) for every product.
Who should check with a doctor first
NuvaMag's label says to talk to a doctor first if you are pregnant or nursing, under 18, or have a medical condition. The ODS also notes some medicine interactions:
- Bisphosphonates (osteoporosis medicines): take them at least 2 hours apart from magnesium.
- Some antibiotics (tetracyclines and quinolones): take them at least 2 hours before or 4 to 6 hours after magnesium.
- Some diuretics can raise or lower your magnesium levels.
- Acid reflux medicines called proton pump inhibitors, taken for a long time, can lower magnesium levels.
Related reading: Magnesium Glycinate for Sleep: What the Evidence Shows and Magnesium vs Ashwagandha vs Melatonin: Which One for Which Job?
Frequently asked questions
Which is better absorbed, glycinate or citrate?
The NIH lists citrate among the forms with higher bioavailability, but its fact sheet does not cover glycinate. There is no NIH comparison of the two. Compare the elemental magnesium per serving instead.
Is magnesium glycinate a laxative?
It is not sold as one. Magnesium citrate is the form sold as a saline laxative. Any form of magnesium can loosen stools if you take too much, which is why the upper limit matters.
Can I take glycinate and citrate together?
You can, as long as your total magnesium from nutrition products and medicines stays at or under 350 mg a day. Count every product, including drink mixes and multivitamins.
Is one form better at night?
Magnesium itself is not tied to the clock. Take it at a time you will remember each day. NuvaMag has no melatonin, so morning or evening both work.
Sources: NIH Office of Dietary Supplements, Magnesium Fact Sheet for Health Professionals; NIH Office of Dietary Supplements, Magnesium Fact Sheet for Consumers; MedlinePlus, Magnesium Citrate.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
