Short answer

We found no direct interaction between Magnesium and Vitamin B12 in the sources below, but they share a caution.

Both have a note about acid-reducing medicines.

Magnesium

What it is: An essential mineral the body uses for muscle and nerve function, blood sugar and blood pressure control, and making protein, bone and DNA.

What the research says: Supplements may lower blood pressure slightly. People who get more magnesium from food tend to have a lower risk of type 2 diabetes, and it matters for bone health.

Cautions

• Adults shouldn't take more than 350 mg a day from supplements unless a clinician advises it.
• Too much from supplements can cause diarrhea, nausea and stomach cramps.

Medicines to check

• Osteoporosis medicines (bisphosphonates) and some antibiotics: take them apart from magnesium
• Diuretics
• Long-term acid-reflux or ulcer medicines can lower magnesium levels

In Holitro: Magnesium Glycinate (133 mg per capsule)

Source: NIH Office of Dietary Supplements: Magnesium: Fact Sheet for Consumers (updated March 2021)

Vitamin B12

What it is: A vitamin that keeps blood and nerve cells healthy and helps make DNA.

What the research says: B12 prevents a type of anemia that makes people tired and weak. People who take metformin or long-term acid reducers may absorb less of it.

Cautions

• It hasn't been shown to cause harm, even at high doses.

Medicines to check

• Metformin and acid-reducing medicines can lower B12 levels (the medicine affects the vitamin, not the other way round)

In Holitro: Vitamin B12 (1000 mcg per capsule)

Source: NIH Office of Dietary Supplements: Vitamin B12: Fact Sheet for Consumers (updated December 2023)

Check with your doctor or pharmacist, especially if you take medication.

Check your stack — free

Educational information only, not medical advice. This reflects general ingredient overlap, not a personalized safety review. Always check with your doctor or pharmacist before combining supplements, especially if you take medication, are pregnant or nursing, or manage a health condition. These statements have not been evaluated by the FDA.