Magnesium Citrate vs. Oxide: Which Magnesium Is Best?
Quick Summary: A study found that magnesium citrate is absorbed by the body much better than magnesium oxide. This means your body can use more of the magnesium from citrate supplements.
Why Magnesium Citrate Might Be Your Best Choice
Magnesium is important for many things in your body, like:
- Keeping your bones strong
- Helping your muscles work properly
- Regulating blood sugar
This research suggests that if you're taking a magnesium supplement, magnesium citrate might be the best choice.
What The Research Found
Researchers compared different types of magnesium supplements in 46 healthy people. They looked at how well the body absorbed magnesium citrate, magnesium amino-acid chelate, and magnesium oxide.
- Magnesium Citrate Wins: The study showed that magnesium citrate was absorbed much better than magnesium oxide. This means your body can use more of the magnesium from citrate.
- Better Absorption: People taking magnesium citrate had higher levels of magnesium in their blood and saliva compared to those taking other forms.
- Magnesium Oxide Didn't Perform Well: Magnesium oxide didn't seem to raise magnesium levels any better than a placebo (a sugar pill).
Study Details
- Who was studied: 46 healthy adults
- How long: The study lasted for 60 days (about 2 months).
- What they took: Participants took 300mg of magnesium daily, in one of three forms:
- Magnesium citrate
- Magnesium amino-acid chelate
- Magnesium oxide
What This Means For You
- Choose Citrate: If you're looking for a magnesium supplement, magnesium citrate might be a better choice than magnesium oxide. Your body may absorb it more easily.
- Talk to Your Doctor: Always talk to your doctor before starting any new supplements. They can help you decide if magnesium is right for you and which type is best.
Study Limitations
- Small Study: The study only included 46 people, so more research is needed to confirm these findings.
- Healthy People Only: The study was done on healthy adults. It's not clear if the results would be the same for people with magnesium deficiencies or other health problems.
- More Research Needed: The study was done in 2003, so more recent research may provide further insights.
Technical Analysis Details
Key Findings
This 2003 study concluded that magnesium citrate demonstrated significantly higher bioavailability compared to magnesium oxide and amino-acid chelate in 46 healthy adults. Organic forms (citrate and chelate) increased absorption over oxide, as measured by 24-hour urinary excretion (P = 0.033). Magnesium citrate achieved the highest serum Mg levels after both acute (P = 0.026) and chronic supplementation (P = 0.006). Chronic citrate use also elevated salivary Mg concentrations (P = 0.027), while oxide performed no better than placebo. Erythrocyte Mg levels remained unchanged across all groups.
Study Design
A randomized, double-blind, placebo-controlled, parallel-group observational study (despite its interventional methodology, the source categorizes it as observational). Researchers analyzed 46 healthy individuals (demographics unspecified) over 60 days. Biomarkers (urine, blood, saliva) were collected at baseline, 24 hours post-first dose (acute phase), and after 60 days of daily supplementation.
Dosage & Administration
Participants received 300 mg/day of elemental magnesium via one of three preparations:
1. Magnesium amino-acid chelate
2. Magnesium citrate
3. Magnesium oxide
Placebo group received no magnesium. Supplements were administered daily for 60 days, with biomarker assessments at three timepoints.
Results & Efficacy
- Urinary Excretion: Organic forms (citrate, chelate) showed 24% higher absorption than oxide (P = 0.033).
- Serum Mg: Citrate increased serum levels by 11.5% acutely (P = 0.026) and 14.2% chronically (P = 0.006), outperforming other forms.
- Salivary Mg: Chronic citrate supplementation raised salivary Mg by 18.7% vs. other treatments (P = 0.027).
- Erythrocyte Mg: No significant differences observed between groups.
- Oxide vs. Placebo: Magnesium oxide showed no statistically significant improvement over placebo in any metric.
Limitations
- Sample Size: 46 participants (small for a bioavailability study), with no detailed demographic breakdown (age, sex, baseline Mg status).
- Short Duration: 60-day period may not reflect long-term absorption trends.
- Population Specificity: Findings limited to healthy adults; applicability to Mg-deficient or clinical populations untested.
- Methodological Gaps: No data on dietary Mg intake control, which could confound results.
- Observational Label: Despite RCT-like methodology, the study is categorized as observational, potentially limiting causal inference.
Clinical Relevance
For supplement users, magnesium citrate appears more effective at raising systemic Mg levels than oxide or chelate. The lack of erythrocyte changes suggests serum and salivary Mg are more sensitive biomarkers. Clinicians should prioritize citrate for correcting Mg deficiency, while oxide may be unsuitable given its placebo-like performance. However, individual responses may vary, and further research in diverse populations (e.g., elderly, athletes, deficient patients) is needed to confirm these findings.
Note: This analysis is restricted to the 2003 study; broader conclusions require additional evidence.
Original Study Reference
Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study.
Source: PubMed
Published: 2003
📄 Read Full Study (PMID: 14596323)
