Magnesium Hydroxide (OTC drug) & Nutrient Depletion
Also searched as Milk of Magnesia (MOM). What the clinical evidence reports, what it may mean, and what to discuss with your pharmacist.
Magnesium Hydroxide (OTC drug) has been associated with depletion of CALCIUM, POTASSIUM and VITAMIN D. This does not mean a deficiency will occur — it means these are worth knowing about and, if you take Magnesium Hydroxide (OTC drug) long-term, worth raising with your pharmacist or healthcare provider.
Take more than one medication? Open the checker with Magnesium Hydroxide (OTC drug) pre-loaded and add the rest to see overlapping nutrient signals.
Reported nutrient depletions with Magnesium Hydroxide (OTC drug)
Each record below is shown as published in our licensed clinical database, with its evidence rating and citations. Expand a section for food sources and talking points.
CALCIUM
Moderate DepletionSTIMULANT LAXATIVES
Prolonged use of high doses of stimulant laxatives can reduce dietary calcium and vitamin D absorption, and possibly lead to osteomalacia. Advise patients to limit stimulant laxatives to short-term use of recommended doses.
Calcium keeps your bones strong and helps your muscles and heart work properly, so it matters more than people realize. Magnesium hydroxide works as a laxative by drawing water into the gut and moving things along quickly, and that faster transit can mean your intestines have less time to absorb calcium from food. With regular, short-term use at normal doses this is rarely a problem, but if you find yourself relying on it often or at higher doses, a conversation with your pharmacist or doctor about your calcium intake is a reasonable step.
What Calcium does & food sources
Calcium builds and maintains bone and is essential for muscle contraction and nerve signaling.
Common food sources:
- Dairy products (milk, yogurt, cheese)
- Fortified plant milks and juices
- Canned fish with bones (sardines, salmon)
- Leafy greens like kale
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
Ask your provider whether bone health monitoring (and vitamin D testing) makes sense with long-term use of an associated medication — a blood calcium level alone does not capture bone calcium status.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Calcium can interfere with the absorption of several medications (some antibiotics, thyroid medication, iron) — separate the doses and confirm timing with your pharmacist. Total intake from food plus supplements matters more than supplements alone.
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Caution: Very high calcium intake has its own risks (kidney stones in susceptible people) — more is not better.
Learn more about this nutrient: Calcium — uses, safety & interactions
References (1)
- Frier BM, Scott RD. Osteomalacia and arthropathy associated with prolonged abuse of purgatives. Br J Clin Pract 1977;31:17-9. DOI
POTASSIUM
Moderate DepletionSTIMULANT LAXATIVES
Long-term use of stimulant laxatives, or acute use of high doses (e.g., in bowel-cleansing regimens), can result in potassium loss and hypokalemia. Advise people to only use stimulant laxatives short-term at recommended doses.
Potassium is a mineral your heart, muscles, and nerves depend on to work properly. Magnesium hydroxide acts as a laxative by drawing water into the intestines and speeding up movement through the gut, and when that happens frequently or at high doses, potassium can be carried out of the body through loose stools before it is fully absorbed. This is rated as a moderate concern, so it is not something to ignore if you use it regularly. If you take magnesium hydroxide often or in large amounts, it is worth asking your pharmacist or doctor whether your potassium levels should be checked.
What Potassium does & food sources
Potassium keeps nerve signals, muscle contractions, and heart rhythm working normally.
Common food sources:
- Bananas and citrus fruits
- Potatoes and sweet potatoes
- Beans and lentils
- Tomatoes and leafy greens
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
Potassium is routinely checked with basic blood work. If you take a medication associated with potassium loss (like some diuretics), ask your provider how often your electrolytes should be monitored.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Do not start potassium supplements on your own. Both low and high potassium can affect heart rhythm, and several common medications (ACE inhibitors, ARBs, potassium-sparing diuretics) raise potassium.
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Caution: Potassium supplementation can be dangerous in kidney disease or alongside potassium-raising medications — this is a decision for your prescriber, guided by lab results.
Learn more about this nutrient: Potassium — uses, safety & interactions
References (3)
- Ritsema GH, Ellers G. Potassium supplements prevent serious hypokalemia in colon cleansing. Clin Radiol 1994;49;874-6.
- Murry JJ, Healy MD. Drug-mineral interactions: a new responsibility for the hospital dietician. J Am Diet Assoc 1991;91:66-73.
- Garabedian-Ruffalo SM, Ruffalo RL. Drug and nutrient interactions. Am Fam Physician 1986;33:165-74.
VITAMIN D
Moderate DepletionSTIMULANT LAXATIVES
Prolonged use of high doses of stimulant laxatives can reduce dietary vitamin D and calcium absorption, leading to hypocalcemia and osteomalacia. Advise patients to limit stimulant laxatives to short-term use of recommended doses.
Vitamin D helps your body absorb calcium and keep your bones strong, so running low on it over time really does matter. When magnesium hydroxide is used as a laxative for long stretches, it can speed food and nutrients through the gut before they get properly absorbed, and vitamin D is one of the nutrients caught in that rush. Because this is rated a moderate depletion concern, it is mainly something to watch for with prolonged or high-dose use, not a quick occasional dose. If you have been relying on this laxative regularly, it is worth a conversation with your pharmacist or doctor about whether your vitamin D levels should be checked.
What Vitamin D does & food sources
Vitamin D helps the body absorb calcium and supports bone, muscle, and immune health.
Common food sources:
- Fatty fish (salmon, mackerel)
- Fortified milk and cereals
- Egg yolks
- Sunlight exposure (the main natural source)
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
A 25-hydroxyvitamin D blood test is the standard way to assess status — ask whether it is appropriate if you take an associated medication long-term, have limited sun exposure, or have bone concerns.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Vitamin D dosing varies a lot between people; some medications change how vitamin D is processed. Your provider can target a dose to your level instead of guessing.
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Caution: Vitamin D is fat-soluble and can accumulate — very high doses over time can cause harm, so follow a clinician-guided plan.
Learn more about this nutrient: Vitamin D — uses, safety & interactions
References (1)
- Frier BM, Scott RD. Osteomalacia and arthropathy associated with prolonged abuse of purgatives. Br J Clin Pract 1977;31:17-9. DOI
This tool is educational and is not a substitute for professional medical advice. An association is not a diagnosis and does not mean a deficiency will occur. Always talk to your pharmacist or healthcare provider before starting, stopping, or changing any medication or supplement.
Disclaimer: This checker finds which nutrients might be depleted by prescription or over-the-counter medications. Each nutrient depletion issue is rated based on clinical significance. Use your own professional judgment prior to making clinical decisions.© 2026 Therapeutic Research Center Licensed records refresh weekly · last updated July 3, 2026.
More about Magnesium Hydroxide (OTC drug)
What drug-induced nutrient depletion means
Some medications can, over time, lower the levels of certain vitamins, minerals, or other nutrients — through reduced absorption, increased loss, or changes in how the body uses them.
Association is not deficiency
An entry here means a depletion has been reported or studied — not that it happens to everyone, or that you are deficient. Dose, duration, diet, and your own health all matter.
Evidence varies by pair
Some drug–nutrient links (like metformin and vitamin B12) are well studied; others rest on limited or preliminary research. Each entry shows the evidence rating from our licensed clinical database.
When to ask about labs
If you take an associated medication long-term, ask your healthcare provider whether monitoring is appropriate for you. Not everyone needs testing — your provider can weigh your dose, duration, and symptoms.
Don't self-supplement blindly
Supplements are not risk-free: some can interact with medications, and some (like potassium or magnesium) can be risky with kidney disease. Talk to your pharmacist before adding anything.
Never stop a medication over this
These medications are prescribed for good reasons, and the benefit usually far outweighs a manageable nutrient consideration. Any change belongs in a conversation with your prescriber.
Food first, usually
For many nutrients, a varied diet covers the gap. Each entry lists common food sources; a supplement is a decision to make with your pharmacist or provider, not a default.
Magnesium Hydroxide (OTC drug) & nutrients: FAQs
Does Magnesium Hydroxide (OTC drug) deplete CALCIUM?
Should I take a supplement because I take Magnesium Hydroxide (OTC drug)?
Should I stop taking Magnesium Hydroxide (OTC drug)?
Where does this information come from?
Questions about Magnesium Hydroxide (OTC drug) and your nutrition?
Ask a licensed pharmacist — free, no appointment needed.
Sources & How We Checked
Nutrient depletion records for Magnesium Hydroxide (OTC drug) are evidence-graded and sourced from the Natural Medicines database, and are displayed as published with their citations.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference for drug-induced nutrient depletions, supplements, and interactions — the basis for this page.
- MedlinePlus, U.S. National Library of Medicine — NIH consumer drug information, used for medication overviews across the site.
Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.