Can I take Omeprazole and Vitamin B12 together?
Drug interaction guide
Originally published 25 Jan 2026
Meets Patient’s editorial guidelines
- DownloadDownload
- Share
- Language
- Discussion
- Audio Version
- Add to preferred sources on Google
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.
Patient picks for Drug interactions

Drug interactions checker
Can I take Mounjaro and Paracetamol together?
Mounjaro may slow down how quickly your body absorbs paracetamol. This means it might take longer for the paracetamol to start working to relieve pain or reduce a fever. However, the total amount of medicine that gets into your system should remain the same.

Drug interactions checker
Can I take Warfarin and Aspirin together?
Taking warfarin and aspirin together significantly increases your risk of serious bleeding. This includes internal bleeding, such as in the stomach or brain, as well as bleeding that is hard to stop from minor cuts or injuries.
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
Join the conversation
Share your thoughts or experiences with others in our patient communities.

Ask, share, connect.
Browse discussions, ask questions, and share experiences across hundreds of health topics.

Feeling unwell?
Assess your symptoms online for free
Sign up to the Patient newsletter
Your weekly dose of clear, trustworthy health advice - written to help you feel informed, confident and in control.
By subscribing you accept our Privacy Policy. You can unsubscribe at any time. We never sell your data.
More in drug interactions checker
- Can I take Amlodipine and Amitriptyline together?
- Can I take Amoxicillin and Clarithromycin together?
- Can I take Anastrozole and Simvastatin together?
- Can I take Apixaban and Metformin together?
- Can I take Aspirin and Evolocumab together?
- Can I take Aspirin and Paracetamol together?
- Can I take Biotin and Isosorbide mononitrate together?
- Can I take CBD oil and Clozapine together?
- Can I take Clopidogrel and Fenofibrate together?
- Can I take Co-codamol and Naproxen together?
- Can I take Evana heavy period relief and Mefenamic acid together?
- Can I take Fexofenadine and Losartan together?
- Can I take Fexofenadine and Sertraline together?
- Can I take Lion's mane and Royal sun together?
- Can I take Lisinopril and Ibuprofen together?
- Can I take Maitake and Turkey tail together?
- Can I take St John's wort and Vitamin D together?
- Can I take Vitamin B complex and Vitamin D together?
- Can I take Warfarin and Aspirin together?