Can I take Omeprazole and Vitamin B12 together?
Drug interaction guide
Originally published 25 Jan 2026
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Taking omeprazole for a long time can make it harder for your body to absorb vitamin B12 from the food you eat. Over several years, this could lead to a vitamin B12 deficiency.
Why this happens
Vitamin B12 is naturally bound to proteins in food. To release the vitamin so your body can use it, you need stomach acid. Omeprazole works by reducing the amount of acid your stomach produces. With less acid available, the B12 stays 'locked' in the food and passes through your system without being fully absorbed.
What you should do
If you take omeprazole for more than 2 to 3 years, ask your doctor to check your vitamin B12 levels with a blood test. You should also watch for signs of low B12, such as feeling very tired, having a sore tongue, or feeling 'pins and needles'. If you need a supplement, high-dose oral tablets or B12 injections usually work well because they don't rely as much on stomach acid for absorption.
Important precautions
Vitamin B12 deficiency
Long-term use of omeprazole can prevent your body from absorbing Vitamin B12 properly, which may lead to nerve damage or anaemia.
Severe diarrhoea
Contact your doctor immediately if you develop severe or persistent watery diarrhoea, as omeprazole can increase the risk of a serious bowel infection called Clostridium difficile.
Lupus (SLE)
Seek medical advice if you develop a skin rash, especially in areas exposed to the sun, as omeprazole can trigger or worsen a rare autoimmune condition called Subacute Cutaneous Lupus Erythematosus.
Food and drink warnings
Alcohol
It is best to avoid or strictly limit alcohol while taking omeprazole. Alcohol can increase the amount of acid your stomach produces, which may worsen your symptoms or make the medicine less effective. Additionally, both alcohol and omeprazole can irritate the stomach lining.
It is best to avoid or strictly limit alcohol while taking Vitamin B12. Heavy alcohol consumption can interfere with the body's ability to absorb Vitamin B12 from the gut and can reduce the amount of the vitamin stored in the liver.
General Food Timing
Omeprazole works best if you take it 30 to 60 minutes before a meal, preferably breakfast. Taking it with food can slow down how quickly the medicine starts to work.
Using other medicines
Taking multiple medicines? Our Medicines Interaction Checker helps you check whether your prescriptions, over-the-counter medicines, and supplements are safe to take together. Simply search for your medicines to see potential interactions and what to do about them.
Disclaimer
This information is for general educational purposes only and should not be relied upon as a substitute for professional medical advice. Always consult your GP, pharmacist, or another qualified healthcare professional before making decisions about your medications. Individual circumstances may vary, and only a healthcare professional who knows your medical history can provide personalised guidance.
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Article history
The information on this page is written and peer reviewed by qualified clinicians.
Article also available in English, German, Spanish, French, Italian, Portuguese, Hindi, Hebrew, Arabic, and Swedish.
25 Jan 2026 | Originally published
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