Birth control pills & Nutrient Depletion
What the clinical evidence reports, what it may mean, and what to discuss with your pharmacist.
Birth control pills has been associated with depletion of RIBOFLAVIN, THIAMINE and VITAMIN B12. This does not mean a deficiency will occur — it means these are worth knowing about and, if you take Birth control pills long-term, worth raising with your pharmacist or healthcare provider.
Take more than one medication? Open the checker with Birth control pills pre-loaded and add the rest to see overlapping nutrient signals.
Reported nutrient depletions with Birth control pills
Each record below is shown as published in our licensed clinical database, with its evidence rating and citations. Expand a section for food sources and talking points.
RIBOFLAVIN
Insignificant DepletionORAL CONTRACEPTIVES
Oral contraceptives may interfere with the absorption of riboflavin, or its conversion to active coenzyme forms. However, studies are conflicting. Some have found reduced levels of flavin adenine dinucleotide (FAD, the active form of riboflavin), reduced urinary riboflavin excretion, or reduced erythrocyte glutathione reductase activity consistent with riboflavin deficiency, in females taking oral contraceptives. However, many of these studies involved females with marginal or deficient dietary riboflavin intake, who used high-dose oral contraceptives (50 mcg ethinyl estradiol/day). When dietary riboflavin intake is adequate, no interaction with oral contraceptives is found. Routine riboflavin supplementation isn't necessary in females taking oral contraceptives.
Riboflavin, a B vitamin your body uses to convert food into energy and keep cells working properly, may be affected slightly by birth control pills. Some research suggests the pill could interfere with how the gut absorbs riboflavin or how the body activates it, but studies have been mixed, and most of the concerns showed up in women who were already not getting enough riboflavin from food and were using older, higher-dose pills. If you eat a reasonably balanced diet, this is very unlikely to be an issue for you, though your pharmacist is always happy to talk it through if you have concerns.
What Vitamin B2 (riboflavin) does & food sources
Riboflavin helps the body produce energy and process other B vitamins.
Common food sources:
- Dairy products and eggs
- Lean meats
- Fortified grains
- Green vegetables
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
Deficiency is uncommon with a varied diet; ask your provider if you have persistent mouth-corner cracking, sore tongue, or unexplained fatigue on a long-term associated medication.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Riboflavin is water-soluble and excess is excreted (it turns urine bright yellow — harmless).
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.
Learn more about this nutrient: Riboflavin — uses, safety & interactions
References (9)
- Tyrer LB. Nutrition and the pill. J Reprod Med 1984;29:547-50..
- Newman LJ, Lopez R, Cole HS, et al. Riboflavin deficiency in women taking oral contraceptive agents. Am J Clin Nutr 1978;31:247-9.. PubMed
- Sanpitak N, Chayutimonkul L. Oral contraceptives and riboflavin nutrition. Lancet 1974;1:836-7.
- Ahmed F, Bamji MS, Iyengar L. Effect of oral contraceptive agents on vitamin nutrition status. Am J Clin Nutr 1975;28:606-15.. PubMed
- Briggs M. Oral contraceptives and vitamin nutrition (letter). Lancet 1974;1:1234-5. DOI
- Mooij PN, Thomas CM, Doesburg WH, Eskes TK. Multivitamin supplementation in oral contraceptive users. Contraception 1991;44:277-88. PubMed
- Roe DA, Bogusz S, Sheu J, et al. Factors affecting riboflavin requirements of oral contraceptive users and non-users. Am J Clin Nutr 1982;35:495-501..
- 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. Riboflavin nutriture of oral contraceptive users. Int J Vitam Nutr Res 1979;49:286-90..
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.
Thiamine is a B vitamin your body uses to convert food into energy and keep your nerves working properly. Some early research suggested that birth control pills might interfere with how well your gut absorbs thiamine, and a few studies noticed slightly lower activity of a thiamine-dependent enzyme in pill users. That said, other studies found no difference at all, and this is officially rated as an insignificant concern, meaning most people on the pill have nothing to worry about here. No routine supplement is needed, but if you ever have questions about your nutrition while on hormonal contraceptives, your pharmacist or doctor is a great starting point.
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.
Learn more about this nutrient: Thiamine — uses, safety & interactions
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.
Vitamin B12 is something your nerves and red blood cells genuinely depend on, so it makes sense to pay attention to it. Birth control pills may cause serum B12 levels to look a little lower on a blood test, most likely because they appear to reduce a transport protein that carries B12 through the bloodstream. Here is the reassuring part though: when researchers have looked more closely, the actual B12 inside tissues and cells stays normal, and levels typically return to baseline once the pill is stopped. For most people on oral contraceptives, this is not something that requires action, but if you have questions or any symptoms you are curious about, your pharmacist or doctor is a great first stop.
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.
Learn more about this nutrient: Vitamin B12 — uses, safety & interactions
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.
More about Birth control pills
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.
Birth control pills & nutrients: FAQs
Does Birth control pills deplete RIBOFLAVIN?
Should I take a supplement because I take Birth control pills?
Should I stop taking Birth control pills?
Where does this information come from?
Questions about Birth control pills and your nutrition?
Ask a licensed pharmacist — free, no appointment needed.
Sources & How We Checked
Nutrient depletion records for Birth control pills are evidence-graded and sourced from the Natural Medicines database, and are displayed as published with their citations.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference for drug-induced nutrient depletions, supplements, and interactions — the basis for this page.
- 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.