Acidophilus and magnesium: can you take them together?

Acidophilus is a live bacterium; magnesium is a mineral. No trial we found tests the two supplements taken together, and there's no known mechanism by which magnesium would interfere with a probiotic the way an antibiotic does. Taking them as separate supplements, or looking for a product with both, is a formulation choice — not something either ingredient's own research has evaluated as a combination.

Two different categories

Acidophilus is a probiotic, dosed in colony-forming units (CFU) and studied strain by strain. Magnesium is an essential mineral, dosed in milligrams, sold in forms like glycinate, citrate, oxide and others that differ in how much elemental magnesium they deliver and how they're tolerated. They're regulated and researched as entirely separate categories. See what is acidophilus for the acidophilus side.

Is there a known interaction?

No trial or case report specific to acidophilus and magnesium appears in the research reviewed for this ingredient. That means the combination hasn't been studied, not that it's been tested and found safe. Magnesium has its own separate consideration unrelated to probiotics: a 2023 review of magnesium's upper intake level found gastrointestinal tolerability — mainly loose stools — was the main limiting effect as the dose rises, which is why supplemental magnesium carries a 350 mg/day upper limit set at that point. More on medications and magnesium in magnesium glycinate and medications: what to check.

A practical note: both can affect digestion

Magnesium at higher doses is associated with looser stools, and acidophilus is being taken specifically because it acts in the digestive tract — so if you start both around the same time and notice a digestive change, it's worth considering that magnesium's own dose-dependent effect is the better-documented explanation, rather than assuming a new interaction between the two. No research reviewed here isolates which ingredient would be responsible if you took them together.

If a product combines them

A combination product should still state the acidophilus strain and CFU count, and the magnesium form and elemental milligram amount, as separate label facts — check both the way you would if you were buying each ingredient on its own, covered in how to choose a good acidophilus supplement.

What's actually been studied for each

What acidophilus has and hasn't been shown to do, strain by strain, is covered in acidophilus benefits: what the research does and doesn't show. Magnesium's own evidence is covered separately in magnesium glycinate benefits — the two reviews don't overlap, because no trial tested them as a pair.

Questions people ask

Can I take acidophilus and magnesium together?

There's no trial testing the combination specifically, and no known mechanism by which the two would interfere with each other. Magnesium's own dose-dependent effect on stool consistency is a separate, well-established consideration worth knowing about either way.

Does magnesium affect how acidophilus works?

No trial reviewed here tested that question. Magnesium doesn't work by killing bacteria, so the specific antibiotic-probiotic concern — fewer live organisms surviving to the gut — doesn't have an established parallel for magnesium.

Related reading: magnesium glycinate dosage and acidophilus and medications: what to check.