Does My Medication Cause Nutrient Depletion?
Some prescription and over-the-counter medications can lower your levels of important vitamins and minerals over time. Search your medication below to see what it may deplete — with evidence ratings and what to discuss with your pharmacist.
Potential nutrient considerations for your selected medication
1 medication checked · 2 nutrients with reported associations. These are talking points for your care team — not a diagnosis.
THIAMINE
Insignificant DepletionCONTRACEPTIVE DRUGS
Some studies have reported a small reduction in activity of the thiamine-dependent enzyme erythrocyte transketolase in females taking oral contraceptives, suggesting mild thiamine deficiency. However, other studies have found no effect. Routine use of thiamine supplements with oral contraceptives isn't necessary.
What Vitamin B1 (thiamine) does & food sources
Thiamine helps convert food into energy and is essential for nerve and heart function.
Common food sources:
- Whole grains and fortified cereals
- Pork
- Beans and lentils
- Nuts and seeds
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
Ask about thiamine if you take an associated medication (for example, a long-term loop diuretic in heart failure) and have symptoms like fatigue or worsening heart failure control — this is an area your care team can weigh.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Thiamine is water-soluble and generally low-risk, but supplementing to treat a suspected problem should still be clinician-guided so the real cause is not missed.
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.
References (4)
- Thorp VJ. Effect of oral contraceptive agents on vitamin and mineral requirements. J Am Diet Assoc 1980;76:581-4.. DOI
- Briggs MH, Briggs M. Thiamine status and oral contraceptives. Contraception 1975;11:151-4. PubMed
- Lewis CM, King JC. Effect of oral contraceptive agents on thiamin, riboflavin, and pantothenic acid status in young women. Am J Clin Nutr 1980;33:832-8..
- Vir SC, Love AH. Effect of oral contraceptive agents on thiamin status. Int J Vit Nutr Res 1979;49:291-5.
VITAMIN B12
Insignificant DepletionCONTRACEPTIVE DRUGS
The data regarding the effects of oral contraceptives on vitamin B12 serum levels are conflicting. Some studies have found reduced serum levels in oral contraceptive users, but others have found no effect despite use of oral contraceptives for up to 6 months. When reduced serum levels are detected, vitamin B12 absorption, urinary excretion, tissue and erythrocyte levels, methylmalonic acid levels, and homocysteine are normal. When oral contraceptive use is stopped, normalization of vitamin B12 levels usually occurs. It's suggested that oral contraceptives reduce production of transcobalamin I, the protein which transports vitamin B12 in the blood. Thus, more of the vitamin is available for tissue uptake and serum levels may be reduced. Vitamin B12 supplements don't seem to increase serum levels of vitamin B12. Lower vitamin B12 serum levels seen with oral contraceptives probably aren't clinically significant.
What Vitamin B12 does & food sources
Vitamin B12 supports red blood cell formation, nerve function, and DNA synthesis.
Common food sources:
- Meat, poultry, and fish
- Eggs and dairy products
- Fortified cereals and nutritional yeast
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
If you take an associated medication long-term, ask your healthcare provider whether checking a vitamin B12 level (sometimes with methylmalonic acid) is appropriate — especially if you notice fatigue, numbness, tingling, or memory changes.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
B12 status is easy to check and low levels are usually straightforward to address, so testing before supplementing is often the sensible order. High-dose folic acid can mask a B12 deficiency, which is one reason B12 and folate questions are best sorted out together with your provider.
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: B12 deficiency can look like other conditions — do not self-diagnose from symptoms alone.
References (8)
- Hielt K, Brynskov J, Hippe E, et al. Oral contraceptives and the cobalamin (vitamin B12) metabolism. Acta Obstet Gynecol Scand 1985;64:59-63.
- Shojania AM. Oral contraceptives: effect on folate and vitamin B12 metabolism. Can Med Assoc J 1982;126:244-7.
- Mooij PN, Thomas CM, Doesburg WH, Eskes TK. Multivitamin supplementation in oral contraceptive users. Contraception 1991;44:277-88. PubMed
- Tyrer LB. Nutrition and the pill. J Reprod Med 1984;29:547-50..
- Prasad AS, Lei KY, Moghissi KS, et al. Effect of oral contraceptives on nutrients. III. Vitamins B6, B12 and folic acid. Am J Obstet Gynecol 1976;125:1063-9. PubMed
- Grace E, Emans SJ, Drum DE. Hematologic abnormalities in adolescents who take oral contraceptive pills. J Pediatrics 1982;101:771-4. PubMed
- Barone C, Bartoloni C, Ghirlanda G, Gentiloni N. Megaloblastic anemia due to folic acid deficiency after oral contraceptives. Haematologica 1979;64:190-5.
- Gardyn J, Mittelman M, Zlotnik J, et al. Oral contraceptives can cause falsely low vitamin B12 levels. Acta Haematol 2000;104:22-4.
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.
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.
Nutrient depletion FAQs
Can medications really deplete nutrients?
Does an entry in this checker mean I am deficient?
Should I take a supplement if my medication appears here?
What labs should I ask about?
Can supplements interact with my medications?
Where does this information come from, and how is it reviewed?
Not sure what your results mean?
Ask a licensed pharmacist — free, no appointment needed.
Sources & How We Checked
Nutrient depletion records are evidence-graded and sourced from the Natural Medicines database, and are displayed as published with their citations. The plain-English education is written and reviewed by licensed HelloPharmacist pharmacists.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference for drug-induced nutrient depletions, supplements, and interactions — the basis for this checker.
- 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.