Can I take Vitamin B12 and Vitamin C 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 high doses of Vitamin C at the same time as Vitamin B12 can reduce the amount of Vitamin B12 your body absorbs and uses. This could potentially lead to a Vitamin B12 deficiency over time if you take them together regularly.
Why this happens
Vitamin C is an antioxidant that can chemically break down Vitamin B12 in the digestive tract, making the B12 inactive and harder for the body to absorb.
What you should do
To avoid this interaction, take Vitamin C at least 2 hours after taking your Vitamin B12 supplement. This allows enough time for the Vitamin B12 to be absorbed properly.
Important precautions
Kidney stones
High doses of vitamin C can increase the amount of oxalate in your urine, which significantly raises the risk of developing kidney stones, especially if you have had them before.
G6PD deficiency
Very high doses of vitamin C can cause oxidative stress and lead to the breakdown of red blood cells (haemolysis) in individuals with G6PD deficiency.
Food and drink warnings
Alcohol
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.
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 Maitake and Turkey tail together?
There are no known harmful interactions between maitake and turkey tail mushrooms. Both are medicinal fungi that are often taken together to support the immune system. However, because both can stimulate the immune system, there is a theoretical possibility of an additive effect.

Drug interactions checker
Can I take Guanfacine and Tizanidine together?
Taking these two medicines together can cause your blood pressure to drop too low and make you feel very sleepy or dizzy. You may feel faint, lightheaded, or even pass out, especially when standing up quickly. It can also significantly slow your heart rate.
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.