Drug-induced nutrient depletion

Ethynodiol Diacetate, Mestranol & Nutrient Depletion

Also searched as Ovulen. What the clinical evidence reports, what it may mean, and what to discuss with your pharmacist.

2Nutrient associations
Insignificant DepletionHighest rating
The bottom line

Ethynodiol Diacetate, Mestranol has been associated with depletion of THIAMINE and VITAMIN B12. This does not mean a deficiency will occur — it means these are worth knowing about and, if you take Ethynodiol Diacetate, Mestranol long-term, worth raising with your pharmacist or healthcare provider.

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The evidence

Reported nutrient depletions with Ethynodiol Diacetate, Mestranol

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.

THIAMINE

Insignificant Depletion

CONTRACEPTIVE DRUGS

Theoretically, contraceptive drugs might reduce thiamine absorption; however, this is not likely to be clinically significant.
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.
Taking Ethynodiol Diacetate, Mestranol? A supplement is not needed for most patients.
Dr. Brian Staiger, Pharm.D explains

Thiamine is a B vitamin your body uses to turn food into energy and keep your nerves working properly. This oral contraceptive may theoretically interfere with how the gut absorbs thiamine, and a handful of studies have picked up a small drop in the activity of a thiamine-dependent enzyme in women taking the pill, though other studies found no change at all. Given the conflicting and limited evidence, this is considered an insignificant depletion for most people, meaning routine supplementation is not expected to be necessary. That said, if you have any concerns, a quick conversation with your pharmacist or doctor can put your mind at ease.

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)
  1. Thorp VJ. Effect of oral contraceptive agents on vitamin and mineral requirements. J Am Diet Assoc 1980;76:581-4.. DOI
  2. Briggs MH, Briggs M. Thiamine status and oral contraceptives. Contraception 1975;11:151-4. PubMed
  3. 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..
  4. Vir SC, Love AH. Effect of oral contraceptive agents on thiamin status. Int J Vit Nutr Res 1979;49:291-5.

VITAMIN B12

Insignificant Depletion

CONTRACEPTIVE DRUGS

Oral contraceptives might reduce levels of vitamin B12; however, research is conflicting.

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.
Taking Ethynodiol Diacetate, Mestranol? A supplement is not needed for most patients.
Dr. Brian Staiger, Pharm.D explains

Vitamin B12 is something your nerves and red blood cells genuinely depend on, so it is worth understanding what the research actually shows here. This oral contraceptive combination may affect a protein called transcobalamin I, which carries B12 through the bloodstream, and some studies have picked up slightly lower B12 blood levels in pill users as a result. That said, the evidence is mixed, and when lower levels do appear, the body seems to be using B12 normally at the tissue level, levels return to normal after stopping the pill, and taking extra B12 does not seem to raise those numbers anyway. For most people on this medication, no action is needed, but if you have questions about your own B12 status, a quick chat with your pharmacist or doctor can put your mind at ease.

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)
  1. Hielt K, Brynskov J, Hippe E, et al. Oral contraceptives and the cobalamin (vitamin B12) metabolism. Acta Obstet Gynecol Scand 1985;64:59-63.
  2. Shojania AM. Oral contraceptives: effect on folate and vitamin B12 metabolism. Can Med Assoc J 1982;126:244-7.
  3. Mooij PN, Thomas CM, Doesburg WH, Eskes TK. Multivitamin supplementation in oral contraceptive users. Contraception 1991;44:277-88. PubMed
  4. Tyrer LB. Nutrition and the pill. J Reprod Med 1984;29:547-50..
  5. 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
  6. Grace E, Emans SJ, Drum DE. Hematologic abnormalities in adolescents who take oral contraceptive pills. J Pediatrics 1982;101:771-4. PubMed
  7. Barone C, Bartoloni C, Ghirlanda G, Gentiloni N. Megaloblastic anemia due to folic acid deficiency after oral contraceptives. Haematologica 1979;64:190-5.
  8. Gardyn J, Mittelman M, Zlotnik J, et al. Oral contraceptives can cause falsely low vitamin B12 levels. Acta Haematol 2000;104:22-4.
Important

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.
Understand the basics

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.

Common questions

Ethynodiol Diacetate, Mestranol & nutrients: FAQs

Does Ethynodiol Diacetate, Mestranol deplete THIAMINE?
Ethynodiol Diacetate, Mestranol has been associated with lower THIAMINE levels in the clinical literature — see the evidence rating and details above. An association is not a guarantee: dose, duration, diet, and your own health all matter. If you take Ethynodiol Diacetate, Mestranol long-term, ask your healthcare provider whether checking your THIAMINE status is appropriate.
Should I take a supplement because I take Ethynodiol Diacetate, Mestranol?
Not automatically. The right first step is usually a conversation with your pharmacist or provider — they can weigh your dose and duration, decide whether testing makes sense, and recommend food-first strategies or a supplement if genuinely needed. Some supplements can interact with medications, so do not add one without checking.
Should I stop taking Ethynodiol Diacetate, Mestranol?
No — never stop a prescribed medication because of a nutrient association. Ethynodiol Diacetate, Mestranol is prescribed for good reasons, and nutrient considerations are usually manageable with monitoring or diet. Any change to your medication belongs in a conversation with your prescriber.
Where does this information come from?
The depletion records come from the Natural Medicines (Therapeutic Research Center) database — an evidence-graded clinical reference — and are displayed as published, with their citations. The plain-English context is written and reviewed by licensed HelloPharmacist pharmacists.

Questions about Ethynodiol Diacetate, Mestranol and your nutrition?

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Sources

Sources & How We Checked

Nutrient depletion records for Ethynodiol Diacetate, Mestranol are evidence-graded and sourced from the Natural Medicines database, and are displayed as published with their citations.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.