Medicines and nutrients interact over time
Beyond the timing issues with minerals, some medications gradually lower the body's level of specific nutrients with long-term use. These are well-documented examples, not reasons to fear necessary medicines [1][2].
Well-documented depletions
- Metformin → vitamin B12. Long-term metformin is associated with lower B12; periodic checking is common [1].
- Acid reducers (PPIs) → vitamin B12 and magnesium. PPIs can reduce B12 absorption and, over a year or more, cause low magnesium [1][2] — see [supplements and acid reducers](/learn/supplements-and-acid-reducers-ppis).
- Loop and thiazide diuretics → potassium, magnesium, thiamin. These increase urinary losses; NIH notes diuretics can increase magnesium loss, and thiamin and potassium can drop too [2].
- Other examples include certain seizure medicines and bone health, and some chemotherapy and folate — worth discussing individually with a clinician.
Why this matters
Depletion develops slowly, so it's easy to miss without monitoring. Low B12 can cause nerve and blood problems; low magnesium and potassium can affect the heart and muscles. Catching these is the point of awareness.
Practical guidance
- Don't stop a prescribed medicine to avoid depletion — that trade-off rarely makes sense.
- Ask about monitoring if you take metformin, a long-term PPI, or a diuretic (for example, periodic B12, magnesium, or potassium checks).
- Replace under guidance when a level is low, at an appropriate dose, rather than guessing.
- Keep a current supplement and medication list for every provider — see [when to talk to a doctor](/learn/when-to-talk-to-a-doctor-about-supplements) [3].