Magnesium Citrate vs. Glycinate: Does Form Actually Matter?
Both are considered well-absorbed forms of magnesium — but they're not identical, and the real difference between them is more about tolerability than raw bioavailability.
Both are genuinely well-absorbed forms
Magnesium citrate and magnesium glycinate are both organic/chelated forms, and both are generally better absorbed than lower-cost inorganic forms like magnesium oxide. Research comparing citrate specifically to oxide found citrate had much higher water solubility (55%) and produced a significantly greater increase in urinary magnesium — a marker of better absorption.
The real difference: tolerability, not just absorption
| Form | Key characteristic |
|---|---|
| Citrate | Slightly higher bioavailability by some measures; has a natural laxative effect, which can cause loose stools at higher doses |
| Glycinate | The glycine carrier reduces competition with calcium/iron for gut absorption; generally much gentler on digestion, lower risk of GI upset |
In practice, this means the "better" choice depends on what you're optimizing for: citrate's mild laxative effect is sometimes used intentionally, while glycinate is often preferred by people who experience digestive discomfort with other magnesium forms.
Sources
Comparative bioavailability research on magnesium citrate vs. magnesium oxide (urinary magnesium excretion as an absorption marker); consumer-education comparison summaries from SingleCare and Nature Made on magnesium citrate vs. glycinate tolerability differences.
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