mineralNot FDA-approvedOTC supplementSold in the US as an OTC dietary supplement and, at higher doses, as an OTC osmotic laxative/bowel-prep productComparative bioavailability studies generally found citrate salts absorbed at least as well as, or better than, magnesium oxide in the cited cohorts
Magnesium CitrateBenefits, Dosage & Interactions
Magnesium citrate is a magnesium preparation commonly used as a dietary supplement and a laxative. It is the magnesium salt of citric acid. Research on Magnesium Citrate focuses on healthy aging. It is typically taken in the evening. Dose, response, and interaction risk vary by individual, so use should be reviewed with a clinician.
How much Magnesium Citrate do people take?
Cited human comparative studies used oral doses in the range of roughly 300-365 mg of elemental magnesium per day from citrate salts, compared against other magnesium compounds. Route reported: Oral, typically as capsules, tablets, or dissolved liquid citrate formulations. Frequency reported: Once daily or split into two doses across the cited trials. These are amounts documented in the cited studies and labels for Magnesium Citrate — they are reported for reference, not a recommendation. Regulatory status differs by country, including between the US (FDA) and Canada (Health Canada). Confirm any amount with a licensed clinician before you take it.
See the full reported protocol and its sourcesResearched by DoseRoutine Research TeamReviewed for accuracy by Nicholas Alexander, RSE, SO, PMPLast updated Educational reference only — not medical advice. Always confirm dosing and safety decisions with a licensed clinician.
Evidence: Moderate — One published human randomized trial; results not yet replicated.
Evidence strengthModerate · 3/4
PreclinicalStrong human evidence
One published human randomized trial; results not yet replicated.
Whole-body biological half-life
Not applicable
Typical timing
in the evening
Default unit
mg
What published protocols report
Ranges documented in the literature, shown for reference. DoseRoutine does not recommend an amount — your prescriber or the product label sets the dose.
- Reported amounts
- Cited human comparative studies used oral doses in the range of roughly 300-365 mg of elemental magnesium per day from citrate salts, compared against other magnesium compounds[1][2][3]
- Route studied
- Oral, typically as capsules, tablets, or dissolved liquid citrate formulations[1][2][3]
Reported for Magnesium Citrate in the cited sources. Published ranges are not dosing advice.
References & evidence
Documents the Magnesium Citrate entry is written from. Each number matches an inline marker above.
- [1]Assessment of bioavailability of Mg from Mg citrate and Mg oxide by measuring urinary excretion in Mg-saturated subjectsWerner T, Kolisek M, Vormann J, Pilchova I, Grendar M, Struharnanska E · Magnesium Research · 2019 · Peer-reviewed · PMID 32162607
- [2]Comparative Clinical Study on Magnesium Absorption and Side Effects After Oral Intake of Microencapsulated MagnesiumPajuelo D, Meissner JM, Negra T, Connolly A, Mullor JL · Nutrients · 2024 · Peer-reviewed · PMID 39770988
- [3]Effects of short-term magnesium supplementation on ionized, total magnesium and other relevant electrolytes levelsIvanovic ND, Radosavljevic B, Zekovic M, Korcok D, Ignjatovic S, Djordjevic B · Biometals · 2022 · Peer-reviewed · PMID 35041150
References & Evidence
Sources on this page that document Magnesium Citrate dosing, timing and safety.
- [1]U.S. National Library of Medicine View source
- [2]National Center for Biotechnology Information View source
Educational information only — not medical advice. Dose ranges vary by person, indication and prescriber.
What is Magnesium Citrate studied for?
What is Magnesium Citrate?Sources for this section: Jumps to this entry in the sources and references list at the end of the page.
Magnesium citrate is a magnesium preparation commonly used as a dietary supplement and a laxative. It is the magnesium salt of citric acid. As an oral supplement, it aims to increase magnesium levels in the body. As a laxative, it works by drawing water into the intestines, which softens the stool and promotes bowel movements. It is available over-the-counter in various forms, including liquids, capsules, and powders. (MedlinePlus)
What does the research say about Magnesium Citrate?
Tap a section to expand.
Magnesium citrate functions through two primary mechanisms depending on its intended use. As a dietary supplement, the magnesium ions from dissociated magnesium citrate are absorbed in the small intestine. Magnesium is an essential mineral involved in over 300 enzymatic reactions in the body, including protein synthesis, muscle and nerve function, blood glucose control, and blood pressure regulation. (NIH ODS)
When used as a laxative, magnesium citrate acts as an osmotic laxative. This means that after oral ingestion, the magnesium ions are poorly absorbed in the gastrointestinal tract. Instead, they remain in the lumen of the intestine and draw water into the bowel through osmosis. This increased water content in the intestine softens the stool and increases its bulk, which stimulates bowel motility and facilitates evacuation. This osmotic effect is what makes it effective for treating constipation and for bowel preparation before medical procedures. (MedlinePlus)
Source for this section: Sources for How does Magnesium Citrate work?: Jumps to this entry in the sources and references list at the end of the page.
Magnesium citrate is primarily recognized for two main benefits:
* **Relief of Constipation:** Its most common use is as an osmotic laxative to treat occasional constipation. By drawing water into the intestines, it softens stool and promotes bowel movements, providing effective relief. (MedlinePlus)
* **Magnesium Supplementation:** As a magnesium salt, it provides an absorbable form of magnesium to the body. Magnesium is a vital mineral that plays a role in numerous physiological processes. Supplementation may be beneficial for individuals with magnesium deficiency, which can manifest as muscle cramps, fatigue, and other symptoms. Research suggests adequate magnesium intake may support bone health, nerve function, muscle contraction, and heart rhythm. (NIH ODS)
While some research explores magnesium's role in conditions like migraines, sleep, and anxiety, the direct benefits of magnesium citrate specifically for these conditions are less definitively established compared to its use for constipation and correcting deficiency. (NIH ODS)
The efficacy of magnesium citrate as a laxative is well-established through clinical practice and has been recognized by health authorities. Its osmotic laxative action is a fundamental principle in gastroenterology. For magnesium supplementation, numerous studies support the role of magnesium in various bodily functions. The NIH Office of Dietary Supplements provides comprehensive summaries of research on magnesium's importance in health. While the absorption rate of magnesium varies between different forms, magnesium citrate is generally considered to have good bioavailability compared to some other magnesium compounds, making it an effective option for supplementation. (NIH ODS)
Evidence for specific health benefits beyond deficiency correction often relies on studies of magnesium in general, rather than magnesium citrate alone. For example, a Cochrane review on magnesium supplementation for migraine prevention noted that while magnesium may be effective, more high-quality studies are needed. Similarly, research into magnesium and sleep or anxiety often examines the broader mineral rather than a specific formulation. (Cochrane, NIH ODS)
Common side effects of magnesium citrate, especially when used as a laxative or in higher doses, include:
* Diarrhea
* Abdominal cramping
* Nausea
* Bloating
* Gas
Less common, but more serious, side effects can occur, particularly with excessive use or in individuals with impaired kidney function:
* Dehydration
* Electrolyte imbalance (e.g., hypermagnesemia, characterized by muscle weakness, lethargy, confusion, low blood pressure, irregular heartbeat, and in severe cases, respiratory depression, coma, or cardiac arrest)
* Allergic reactions (rare, symptoms include rash, itching, swelling, severe dizziness, trouble breathing)
If you experience any severe or persistent side effects, discontinue use and seek medical attention immediately. This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Source for this section: Sources for What are the side effects of Magnesium Citrate?: Jumps to this entry in the sources and references list at the end of the page.
Individuals should exercise caution when using magnesium citrate, particularly:
* **Kidney Impairment:** People with kidney disease or impaired kidney function are at a higher risk of developing hypermagnesemia (excessive magnesium levels) because their kidneys may not be able to excrete magnesium efficiently. (MedlinePlus)
* **Dehydration Risk:** When used as a laxative, magnesium citrate can cause significant fluid loss. It is crucial to drink plenty of fluids to prevent dehydration, especially after bowel preparation. (MedlinePlus)
* **Electrolyte Imbalance:** Prolonged or excessive use, especially as a laxative, can lead to electrolyte disturbances, which can be dangerous. (MedlinePlus)
* **Heart Conditions:** Individuals with certain heart conditions, such as heart block, should use magnesium supplements with caution and under medical supervision. (DrugBank)
* **Bowel Obstruction:** Do not use magnesium citrate as a laxative if you have symptoms of appendicitis, a blocked bowel (intestinal obstruction), or severe abdominal pain, nausea, or vomiting. (MedlinePlus)
* **Children:** Use in children, particularly as a laxative, should be done under the guidance of a healthcare professional. (MedlinePlus)
* **Pregnancy and Breastfeeding:** Consult a healthcare provider before using magnesium citrate if pregnant or breastfeeding. (MedlinePlus)
This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Source for this section: Sources for Who should avoid Magnesium Citrate?: Jumps to this entry in the sources and references list at the end of the page.
Magnesium citrate is contraindicated in several circumstances due to potential risks:
* **Kidney Failure or Severe Renal Impairment:** As the kidneys are responsible for magnesium excretion, individuals with significant kidney dysfunction are at high risk of developing hypermagnesemia, which can be life-threatening. (DrugBank)
* **Bowel Obstruction or Ileus:** Use of osmotic laxatives like magnesium citrate can worsen these conditions and should be avoided. (MedlinePlus)
* **Appendicitis or Undiagnosed Abdominal Pain:** Using a laxative with acute abdominal pain of unknown cause can be dangerous and may mask symptoms of serious conditions. (MedlinePlus)
* **Myasthenia Gravis:** Magnesium can sometimes exacerbate muscle weakness in individuals with myasthenia gravis. (DrugBank)
* **Perforated Bowel:** Any condition involving a perforation of the gastrointestinal tract is a strict contraindication. (DrugBank)
* **Allergy:** Known hypersensitivity or allergic reaction to magnesium citrate or any of its components. (EMA SmPC)
This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Source for this section: Sources for When should Magnesium Citrate not be taken?: Jumps to this entry in the sources and references list at the end of the page.
Magnesium citrate can interact with several medications and other compounds. Always inform your healthcare provider about all supplements and medications you are taking.
* **Antibiotics (especially Tetracyclines and Fluoroquinolones):** Magnesium can bind to these antibiotics in the digestive tract, reducing their absorption and effectiveness. It is generally recommended to take magnesium products at least 2-4 hours apart from these antibiotics. (MedlinePlus)
* **Bisphosphonates (e.g., Alendronate, Risedronate):** Similar to antibiotics, magnesium can interfere with the absorption of bisphosphonates, reducing their efficacy for bone health. Separate administration by at least 2 hours. (MedlinePlus)
* **Diuretics (Water Pills):** Some diuretics (like loop and thiazide diuretics) can increase magnesium excretion, while others (potassium-sparing diuretics) can decrease it. Monitoring magnesium levels may be necessary. (MedlinePlus)
* **Digoxin:** High magnesium levels can affect heart rhythm and interact with digoxin, a medication used for heart conditions. (DrugBank)
* **Muscle Relaxants:** Magnesium can have muscle-relaxing effects, and combining it with other muscle relaxants may potentiate these effects. (DrugBank)
* **Calcium Supplements:** High doses of both magnesium and calcium can compete for absorption. While not typically a strict contraindication, mindful dosing and timing may be beneficial. (NIH ODS)
* **Potassium-Sparing Diuretics:** These can increase magnesium levels in the body, potentially leading to hypermagnesemia if combined with magnesium supplementation. (FDA label)
This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Source for this section: Sources for What should you not mix with Magnesium Citrate?: Jumps to this entry in the sources and references list at the end of the page.
The typical timing for magnesium citrate depends significantly on its intended use:
* **For Constipation Relief (Laxative):** It is usually taken as a single dose, often in the evening, to promote a bowel movement within a few hours or overnight. When used for bowel preparation before a medical procedure, a specific dosing schedule prescribed by a clinician must be followed. (MedlinePlus)
* **For Magnesium Supplementation:** Magnesium citrate can be taken at any time of day, either with or without food. Some people prefer to take it at bedtime, as magnesium may have a calming effect and contribute to better sleep. Taking it with food may help reduce gastrointestinal upset in some individuals. The daily dose direction for supplementation needs to be set by a licensed clinician. (NIH ODS)
Source for this section: Sources for When should you take Magnesium Citrate?: Jumps to this entry in the sources and references list at the end of the page.
Put it into practice
Reading about Magnesium Citrate is the first step — DoseRoutine helps you act on it. These free tools turn what you just learned into a routine.
What interacts with Magnesium Citrate?
| Interacts with | Severity | Type | What happens | What to do |
|---|---|---|---|---|
| Levothyroxine | Caution | Compound pairConfidence: theoretical | Divalent cations chelate levothyroxine in the gut and reduce absorption by up to 30%.Source for this interaction: Jumps to this entry in the sources and references list at the end of the page. | Take levothyroxine on empty stomach; separate mineral supplements by at least 4 hours.Suggested separation: 4 h |
| Any + | Caution | Category ruleConfidence: theoretical | Divalent cations chelate levothyroxine in the gut and reduce absorption by up to 30%.Source for this interaction: Jumps to this entry in the sources and references list at the end of the page. | Take levothyroxine on empty stomach; separate mineral supplements by at least 4 hours.Suggested separation: 4 h |
Frequently asked questions about Magnesium Citrate
Magnesium is available in many forms, each with varying bioavailability and uses. Magnesium citrate is known for its good absorption and is also effective as an osmotic laxative. Other forms like magnesium oxide are less bioavailable and primarily used as a laxative. Magnesium glycinate and magnesium L-threonate are often favored for their higher bioavailability and specific uses like relaxation or cognitive support, respectively. The best form depends on the individual's needs. (NIH ODS)
Yes, magnesium citrate can be used for daily supplementation due to its relatively good bioavailability. However, because it also has laxative properties, individuals sensitive to laxative effects might experience loose stools if taken daily, especially at higher doses. Other forms of magnesium may be preferred for daily, long-term supplementation if the laxative effect is undesirable. Always consult a healthcare provider for personalized recommendations regarding dosage and suitable form for daily use.
When taken as an oral laxative, magnesium citrate typically produces a bowel movement within 30 minutes to 6 hours. Individual response times can vary based on factors like dosage, individual metabolism, and the presence of food in the stomach. (MedlinePlus)
The use of magnesium citrate during pregnancy should be discussed with a healthcare provider. While magnesium is essential during pregnancy, and magnesium sulfate is used in some obstetric situations, oral magnesium citrate for constipation or supplementation should only be used under medical guidance due to the potential for dehydration and electrolyte imbalance, especially when used as a laxative. (MedlinePlus)
Yes, it is possible to overdose on magnesium, particularly if you have kidney problems or take very high doses. Symptoms of hypermagnesemia can range from mild (nausea, vomiting, diarrhea, muscle weakness, lethargy) to severe (low blood pressure, irregular heartbeat, respiratory depression, even cardiac arrest). Always adhere to recommended dosages and seek immediate medical attention if you suspect an overdose. (MedlinePlus)
As a mineral, Magnesium Citrate can overlap with other supplements, prescription medicines, hormones and peptides. Because Magnesium Citrate is usually taken in the evening, most avoidable conflicts come from what else lands in that same window. Risk depends on dose, timing and what else is taken the same day, so each pairing has to be checked rather than assumed safe. The free checker at https://doseroutine.com/interaction-checker covers Magnesium Citrate with no sign-up.
Whether Magnesium Citrate fits alongside testosterone replacement therapy depends on the protocol — dose, ester and ancillaries such as HCG or anastrozole — and on current bloodwork. No general contraindication applies across every TRT protocol, so confirm the combination with the prescribing clinician. See the free TRT interaction reference: https://doseroutine.com/trt-supplement-interactions
"Peptides" is not one category — healing peptides, GLP-1 agonists, growth-hormone secretagogues and melanocortins each behave differently next to Magnesium Citrate. Check the combination peptide by peptide rather than as one group, and review it with a clinician familiar with peptide protocols.
Published frequency for Magnesium Citrate varies by protocol and formulation, so the label or prescription is what sets it. It is typically taken in the evening. Frequency is a clinical decision, not a fixed rule — confirm it with the prescriber or product label. Comparison of apps that keep a schedule like this: https://doseroutine.com/best-dose-tracking-apps
The effect of a missed dose of Magnesium Citrate depends on the protocol and formulation you are on. Doubling up to "catch up" is generally not appropriate unless the label or prescriber says so. Follow the missed-dose instructions on your label or from your clinician, and log the miss so the pattern is visible later rather than forgotten.
For Magnesium Citrate the useful record is the dose, the time it was actually taken, and what else was taken in the same window. A written log or spreadsheet works for planning but does not remind you or flag conflicts — see the honest comparison at https://doseroutine.com/vs/spreadsheet and the wider roundup at https://doseroutine.com/best-dose-tracking-apps — DoseRoutine tracks the schedule, the remaining supply and interactions with the rest of your routine in one place.
Cited human comparative studies used oral doses in the range of roughly 300-365 mg of elemental magnesium per day from citrate salts, compared against other magnesium compounds. Route reported: Oral, typically as capsules, tablets, or dissolved liquid citrate formulations. Frequency reported: Once daily or split into two doses across the cited trials. These are amounts documented in the cited studies and labels for Magnesium Citrate — they are reported for reference, not a recommendation. Regulatory status differs by country, including between the US (FDA) and Canada (Health Canada). Confirm any amount with a licensed clinician before you take it.
Which studies looked at Magnesium Citrate?
Peer-reviewed research indexed in PubMed. Each entry links to the original record.
- 1.Bioavailability and pharmacokinetics of magnesium after administration of magnesium salts to humans(opens PubMed in a new tab)Am J Ther · 2001 · PMID 11550076 · https://pubmed.ncbi.nlm.nih.gov/11550076/
- 2.Magnesium bioavailability from magnesium citrate and magnesium oxide(opens PubMed in a new tab)J Am Coll Nutr · 1990 · PMID 2407766 · https://pubmed.ncbi.nlm.nih.gov/2407766/
- 3.Magnesium in Migraine Prophylaxis-Is There an Evidence-Based Rationale? A Systematic Review(opens PubMed in a new tab)Headache · 2018 · PMID 29131326 · https://pubmed.ncbi.nlm.nih.gov/29131326/
- 4.Magnesium supplementation improves indicators of low magnesium status and inflammatory stress in adults older than 51 years with poor quality sleep(opens PubMed in a new tab)Magnes Res · 2010 · PMID 21199787 · https://pubmed.ncbi.nlm.nih.gov/21199787/
Sources cited on this page
Specific documents referenced by the numbered markers above. Each number matches the marker in the text.
- MedlinePlus(opens in a new tab)U.S. National Library of Medicine · medlineplus.gov/druginfo/meds/a619019.html
- PubChem CID 6099959(opens in a new tab)National Center for Biotechnology Information · pubchem.ncbi.nlm.nih.gov/compound/6099959
Verify at
Publisher search links for Magnesium Citrate. These are places to check the information — they are not citations, so they are not numbered.
- NIH Office of Dietary Supplements(publisher search, opens in a new tab)National Institutes of Health · publisher search
- DrugBank(publisher search, opens in a new tab)DrugBank Online · publisher search
- Cochrane Library(publisher search, opens in a new tab)Cochrane · publisher search
- FDA-approved labeling (DailyMed)(publisher search, opens in a new tab)U.S. Food and Drug Administration · publisher search
- European Medicines Agency(publisher search, opens in a new tab)European Medicines Agency · publisher search
- PubMed literature search(publisher search, opens in a new tab)National Library of Medicine · publisher search
- Wikipedia entry(publisher search, opens in a new tab)Wikipedia · publisher search
DoseRoutine compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician. How we source and review this information.
What is the short answer on Magnesium Citrate?
Plain-text summary, safe to quote verbatim:
Magnesium citrate is a magnesium preparation commonly used as a dietary supplement and a laxative. It is the magnesium salt of citric acid. Research on Magnesium Citrate focuses on healthy aging. It is typically taken in the evening. Dose, response, and interaction risk vary by individual, so use should be reviewed with a clinician.
Source: DoseRoutine — https://doseroutine.com/library/magnesium-citrate
Magnesium Citrate cheat sheet
DoseRoutine cheat sheet · Mineral
Magnesium Citrate
Magnesium citrate is a magnesium preparation commonly used as a dietary supplement and a laxative. It is the magnesium salt of citric acid.
Evidence
Moderate
One published human randomized trial; results not yet replicated.
Studied range
Cited human comparative studies used oral doses in the range of roughly 300-365 mg of elemental magnesium per day from citrate salts, compared against other magnesium compounds
Route
Oral, typically as capsules, tablets, or dissolved liquid citrate formulations
Frequency studied
Once daily or split into two doses across the cited trials
Half-life
Not directly reported; magnesium is handled via renal excretion, which the urinary-excretion bioavailability study used as its outcome measure
Timing
in the evening
Not FDA-approvedOTC supplementSold in the US as an OTC dietary supplement and, at higher doses, as an OTC osmotic laxative/bowel-prep productComparative bioavailability studies generally found citrate salts absorbed at least as well as, or better than, magnesium oxide in the cited cohortsLongevity
Key references
- Assessment of bioavailability of Mg from Mg citrate and Mg oxide by measuring urinary excretion in Mg-saturated subjects (2019)
- Comparative Clinical Study on Magnesium Absorption and Side Effects After Oral Intake of Microencapsulated Magnesium (2024)
- Effects of short-term magnesium supplementation on ionized, total magnesium and other relevant electrolytes levels (2022)
Studied ranges, not dosing advice. Not medical advice — talk to a clinician. doseroutine.com/library/magnesium-citrate
Cite this page
Using this in an article, AI answer, or research note? Please attribute:
DoseRoutine. (2026). Magnesium Citrate — Overview, Benefits & Side Effects. Retrieved from https://doseroutine.com/library/magnesium-citrate
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