Minerals
Magnesium Citrate — timing, dose & interactions
One of the better-absorbed, inexpensive forms: in a randomized comparison it raised magnesium levels more than amino-acid chelate or oxide. Its laxative effect is useful for constipation but limits the dose some people tolerate.
Timing
When to take it
Any time of day, with a glass of water. Larger doses loosen stools — it's also sold as a laxative.
Dose note. UL applies to all supplemental magnesium combined (not food); mainly to prevent diarrhea.
Interactions
Magnesium Citrate with other supplements
Magnesium Citrate + Calcium
Very high calcium may reduce magnesium absorption
Magnesium Citrate + Zinc
Very high zinc can reduce magnesium absorption
Magnesium Citrate + Vitamin D3
Magnesium is required to activate vitamin D
Magnesium Citrate + Psyllium Husk
Fiber can reduce magnesium absorption
Magnesium Citrate + Potassium
Low magnesium makes low potassium hard to fix
Magnesium Citrate + Magnesium
Two forms of magnesium
Magnesium Citrate + Magnesium Glycinate
Two forms of magnesium
Magnesium Citrate + Magnesium L-Threonate
Two forms of magnesium
Magnesium Citrate + Magnesium Malate
Two forms of magnesium
Magnesium Citrate + Magnesium Oxide
Two forms of magnesium
Safety
Medications & health conditions
Magnesium reduces levothyroxine absorption. Magnesium binds levothyroxine in the gut and can lower thyroid hormone levels. Keep it at least 4 hours away from your thyroid medication.
Magnesium blocks absorption of these antibiotics. Magnesium binds tetracycline and quinolone antibiotics in the gut, which can make the antibiotic less effective. Typically take the antibiotic at least 2 hours before or 4–6 hours after magnesium — the exact spacing depends on the drug, so follow its label.
Magnesium can build up with kidney disease. The kidneys remove excess magnesium. With reduced kidney function, supplements can cause dangerous hypermagnesemia.
PPIs can lower magnesium. Long-term PPI use is linked to low blood magnesium. That's a reason to have your level checked, not a reason to avoid magnesium.
Magnesium blocks HIV integrase inhibitors. The labels advise taking dolutegravir or bictegravir 2 hours before or 6 hours after products containing magnesium.
Buying guide
What to look for on the label
Magnesium Citrate
- Capsules or powder dosed in elemental magnesium
- Split the dose if it upsets your stomach
FAQ
Common questions
When is the best time to take Magnesium Citrate?
Breakfast / Dinner. Any time of day, with a glass of water. Larger doses loosen stools — it's also sold as a laxative.
Should Magnesium Citrate be taken with food?
It can be taken with or without food. Any time of day, with a glass of water. Larger doses loosen stools — it's also sold as a laxative.
Can you take Magnesium Citrate with Calcium?
Yes, at normal doses. At high calcium doses, spacing them out is a reasonable precaution. No action needed at typical doses. If you take ≥1,000 mg calcium from supplements, take magnesium at a different time (e.g. bedtime).
Can you take Magnesium Citrate with Zinc?
Yes — this only matters at very high zinc doses. Keep zinc within the 40 mg/day upper limit.
Can you take Magnesium Citrate with Vitamin D3?
Yes — adequate magnesium helps vitamin D work, especially at higher D doses. Make sure magnesium intake is adequate if you take vitamin D, especially at higher doses. They do not need to be taken at the same time.
Can you take Magnesium Citrate with Psyllium Husk?
Separate them by about 2 hours. Take psyllium at least 2 hours apart from magnesium.
Sources