Magnesium supplements come in at least seven common forms, each bound to a different compound — citric acid, glycine, taurine, malic acid, and others. The form affects how much elemental magnesium you get per pill, how well your body absorbs it, and what you pay per month. Most buyers pick a form based on a blog recommendation and never compare costs, which is a mistake: the price difference between forms can be 3–5× for the same amount of elemental magnesium.
This page compares all seven magnesium forms available on TrueServing by typical use case, bioavailability, and real cost per month at 200mg of elemental magnesium per day.
The table below shows the average monthly cost for each magnesium form, calculated from the 10 cheapest non-powder products in each category. All costs are normalized to 200mg of elemental magnesium per day so you can compare directly across forms.
| Form | Used For | Typical Dose | Avg. Cost/Month |
|---|---|---|---|
| Magnesium Oxide | General supplementation (budget) | 400mg | $0.82 |
| Magnesium Citrate | General supplementation, digestive regularity | 200mg | $2.75 |
| Magnesium Glycinate | Sleep, relaxation, general supplementation | 200mg | $3.45 |
| Magnesium Malate | Energy, muscle comfort | 200mg | $3.85 |
| Magnesium Carbonate | General supplementation, antacid support | 200mg | $4.13 |
| Magnesium Taurate | Cardiovascular health, blood pressure | 200mg | $4.79 |
| Magnesium Threonate | Cognitive support, brain health | 2,000mg* | $22.33 |
*Magnesium Threonate is dosed by compound weight (Magnesium L-Threonate), not elemental magnesium. 2,000mg of the compound provides approximately 144mg of elemental magnesium.
Magnesium Oxide averages $0.82/month — the cheapest form by a wide margin. Magnesium Threonate averages $22.33/month, roughly 27× more expensive for the same elemental dose.
For general supplementation on a budget: Magnesium oxide delivers the most elemental magnesium per capsule at the lowest cost. Bioavailability is lower than chelated forms, but the per-dollar value is hard to beat if you just need to hit your daily target.
For sleep and relaxation: Magnesium glycinate is the most popular choice. Glycine itself has calming properties, and the chelated form is well absorbed without laxative effects.
For cognitive support and brain health: Magnesium threonate (as Magnesium L-Threonate) is the only form specifically studied for brain penetration. It's significantly more expensive per milligram of elemental magnesium than other forms, and the evidence base is smaller — primarily a few clinical trials on cognitive function in older adults. If brain health is not your primary goal, other forms deliver elemental magnesium at a fraction of the cost.
For digestive regularity: Magnesium citrate has a mild osmotic laxative effect at higher doses. It's also one of the most bioavailable forms and moderately priced — a good all-around choice.
For cardiovascular support: Magnesium taurate pairs magnesium with taurine, which has its own cardiovascular benefits. The elemental magnesium yield per capsule is low (you need more pills), which makes it one of the more expensive forms on a per-mg basis.
For energy and muscle comfort: Magnesium malate combines magnesium with malic acid, a compound in the energy production cycle. Mid-range pricing and moderate bioavailability.
For antacid support: Magnesium carbonate reacts with stomach acid during absorption, giving it a mild antacid effect. Moderately priced, moderate bioavailability.
Chelated forms (glycinate, taurate, malate) are better absorbed per milligram than inorganic forms (oxide, carbonate). But inorganic forms pack more elemental magnesium per capsule, so you can take fewer pills to reach the same dose. A product with lower absorption but higher dose may deliver the same net magnesium at lower cost.
The practical takeaway: if you tolerate oxide well (no digestive issues), it's the cheapest path to adequate magnesium. If you want better absorption and fewer side effects, citrate or glycinate are the standard upgrades.
Magnesium supplementation is supported by strong evidence for preventing and correcting magnesium deficiency, which affects an estimated 50% of Americans. The RDA is 310–420mg/day depending on age and sex. Common side effects at higher doses include loose stools and digestive discomfort, particularly with oxide and citrate. The tolerable upper intake level for supplemental magnesium is 350mg/day (this applies to supplements only, not dietary magnesium). All seven forms covered here have established safety profiles at standard doses.
For detailed product rankings and filtering within any form, visit the individual comparison pages: