Types of Magnesium: All 8 Forms Compared for Canada (2026)
In Canada, check the licence before you pick a form. The licences for two popular “bisglycinate” capsules on Amazon.ca (Webber Naturals and CanPrev) also list magnesium oxide, and Health Canada recalled two more in late 2025 for oxide they did not declare. A pure bisglycinate or a citrate is a good everyday choice; citrate was the cheapest per mg at the list prices we could find.
Glycinate
Jamieson 100% Pure Magnesium Bisglycinate 100 mg
100 mg in 1 capsule a day, bisglycinate only (NPN 80131651), CA$0.18 a day at Jamieson’s price
Check priceCitrate
Webber Naturals Magnesium Citrate 150 mg
150 mg a capsule (NPN 80005581), CA$0.30 per 300 mg, the lowest cost per mg at list price
Check priceGlycinate, Bisglycinate and “Buffered”: Check the Licence
Glycinate and bisglycinate name the same compound. The Canadian catch is the “buffered” capsule. The licences for Webber Naturals Magnesium Bisglycinate 200 mg (NPN 80075245) and CanPrev Magnesium Bis-Glycinate 200 Gentle (NPN 80115340) list both bisglycinate and oxide. The licences for Jamieson 100% Pure Magnesium Bisglycinate 100 mg, Nutritionn Magnesium Glycinate 200 mg and the Natural Factors Magnesium Bisglycinate 200 mg Powder list bisglycinate alone.
In November 2025 Health Canada recalled Life Brand and MapleLife bisglycinate 200 mg because they held oxide the label did not declare. Declared oxide is legal; undeclared oxide is not.
Which Form for Which Goal, With a Canadian Product
| Goal | What was tested | On Amazon.ca |
|---|---|---|
| Sleep | Bisglycinate: one 2025 trial (250 mg) found a small benefit. No form is proven best. | Jamieson 100% Pure Magnesium Bisglycinate 100 mg |
| Constipation | Oxide or citrate. In 2 trials, 68% improved on oxide vs 19% on placebo. | Webber Naturals Magnesium Citrate 150 mg |
| Leg cramps | Weak evidence. For night cramps in older adults a Cochrane review found magnesium unlikely to help; one positive trial used oxide. In pregnancy, one trial found fewer cramps on 300 mg of bisglycinate a day. | Natural Factors Magnesium 250 mg (oxide, the form in that trial) |
| Low intake from food | Citrate gives the most magnesium per dollar at the Canadian list prices we found. | Webber Naturals Magnesium Citrate 150 mg |
| Stress or anxiety | No form is proven. Small studies only; a pure bisglycinate is a simple choice. | Nutritionn Magnesium Glycinate 200 mg |
| Migraine | Trials used up to 600 mg a day, above the 350 mg limit. Ask your doctor first. | No product: only with your doctor’s advice |
All 8 Magnesium Forms: The Canadian Picture
| Form | Magnesium by weight | What it is and what it is for | In Canada |
|---|---|---|---|
| Glycinate | ~14% | Magnesium bound to the amino acid glycine. Chosen for being easy on the stomach: in one small trial it was better tolerated than oxide. Tested for sleep (250 mg) and for leg cramps in pregnancy (300 mg). | Licensed as “bisglycinate.” Two of the six licences we read also list oxide. Product we reviewed: Jamieson 100% Pure Magnesium Bisglycinate 100 mg. |
| Citrate | ~16% | Magnesium bound to citric acid, an everyday form. Small studies found it absorbed better than oxide (NIH). Large doses loosen stools. | The cheapest per mg at the Canadian list prices we found. Three licensed brands sell it on Amazon.ca. Product we reviewed: Webber Naturals Magnesium Citrate 150 mg. |
| Chloride | ~12% | A magnesium salt sold as tablets, flakes and sprays. By mouth it absorbed better than oxide in one small study. NIH lists it among the forms most linked to diarrhea. | Allowed, but we found no licensed chloride capsule on Amazon.ca. If you buy one elsewhere, look for the NPN on the label. |
| Malate | ~15% | Magnesium bound to malic acid, sold for energy and fibromyalgia. A 2019 review found little or no effect on fibromyalgia pain. | Allowed. On Amazon.ca we found it only mixed into a citrate capsule. |
| Taurate | ~9% | Magnesium bound to taurine, sold for heart health. The idea comes from a 1996 theory paper; we found no human trial of this form. | Allowed, but we found no licensed taurate product on Amazon.ca. One you find there may be an import with no NPN. |
| L-Threonate | ~7% | Made to raise magnesium in the brain, which was shown in rats. Sold for memory; two small human trials were paid for by the maker. About 7% is magnesium. | Licensed, at small doses: NOW Magtein’s licence gives 60 mg of magnesium in 1 capsule a day; Natural Factors Regenerlife gives 48 mg a capsule, 3 a day (144 mg). Product we reviewed: NOW Magtein Magnesium L-Threonate. |
| Oxide | ~60% | The most magnesium per tablet, but only about 4% was absorbed in one study. Used for constipation and heartburn. | Allowed. It is the hidden part of “buffered” bisglycinate capsules. Product we reviewed: Natural Factors Magnesium 250 (oxide blend). |
| Sulfate | ~10% | Epsom salt. Swallowed, it is a strong laxative; hospitals give it by IV. Not a daily supplement. | Allowed as a source, but we found no licensed capsule on Amazon.ca. It is mostly sold as Epsom salt for the bath. |
More licensed choices on Amazon.ca: citrate from Natural Factors Magnesium Citrate 150 mg (150 mg a capsule) and NOW Magnesium Citrate 200 mg (200 mg a tablet). For how each form absorbs and what the studies found, see the US forms page.
Which Form Costs Least in Canada?
| Product | Source on the licence | Per 300 mg | Buy |
|---|---|---|---|
| Webber Naturals Magnesium Citrate 150 mg | citrate | CA$0.30 | Check price |
| Webber Naturals Magnesium Bisglycinate 200 mg (buffered: part oxide) | bisglycinate + oxide | CA$0.32 | Check price |
| Jamieson 100% Pure Magnesium Bisglycinate 100 mg | bisglycinate | CA$0.53 | Check price |
Most brands sell through stores and show no price of their own, so we could price only these three. At list price, the buffered Webber capsule costs less per mg than pure bisglycinate because part of it is oxide, which costs less and is absorbed less. Buy it only if you are fine with that mix.
Safety and Medicines
- Health Canada’s upper limit for magnesium from supplements is 350 mg a day from age 9. Licensed labels may go up to 500 mg for adults, with a diarrhea warning.
- If you have kidney disease, ask your doctor before you take magnesium. Weak kidneys cannot clear the extra, so it can build up (NIH).
- Antibiotics: take tetracyclines (such as doxycycline) or quinolones (such as ciprofloxacin) at least 2 hours before or 4 to 6 hours after magnesium (NIH).
Frequently Asked Questions
Which magnesium should I buy in Canada?
Start with the licence, then the form. A pure bisglycinate such as Jamieson 100% Pure Magnesium Bisglycinate 100 mg (NPN 80131651) or a citrate such as Webber Naturals Magnesium Citrate 150 mg (NPN 80005581) suits most adults. Skip a “bisglycinate” whose licence also lists oxide unless the lower price is what you want.
What does “buffered” magnesium bisglycinate mean?
The capsule mixes magnesium bisglycinate with magnesium oxide, usually to fit 200 mg in one capsule. The product licence lists both sources. You get part oxide, which was about 4% absorbed in one study.
How do I check which form is in my bottle?
Read the medicinal ingredient line: the source is in brackets after the magnesium amount. Or look up the NPN in Health Canada’s Licensed Natural Health Products Database, which lists each source.
Why can a Canadian label say up to 500 mg?
Health Canada’s monograph lets adult products go up to 500 mg a day, but any label above 350 mg must carry a diarrhea warning. The upper limit for magnesium from supplements is 350 mg a day from age 9.
Related Guides
- Best magnesium supplement in Canada · how much magnesium per day in Canada
- US forms page (every study behind the form facts) · glycinate vs citrate
Sources
- Health Canada. Multi-Vitamin/Mineral Supplements monograph (June 26, 2026): magnesium sources and doses.
- Health Canada. Licensed Natural Health Products Database: each NPN on this page, read October 15, 2026. Recalls: Life Brand; MapleLife.
- US NIH Office of Dietary Supplements. Magnesium fact sheet for health professionals (migraine doses, forms). Firoz M, Graber M. 2001. PubMed 11794633.
- Trials behind the form lines: Schuette 1994, PubMed 7815675; Schuster 2025, PubMed 40918053; Supakatisant 2015, PubMed 22909270; Garrison 2020 (Cochrane), PubMed 32956536; Ferreira 2019, PubMed 31150373; McCarty 1996, PubMed 8692051; Slutsky 2010, PubMed 20152124.
- Products: Amazon.ca listings and the Jamieson and Webber Naturals websites, read October 15, 2026.