Can I take Simvastatin 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
There is no known harmful interaction between simvastatin and vitamin B12. It is generally safe to take these two together.
Why this happens
Simvastatin is a cholesterol-lowering medication (statin) processed primarily by the liver, while vitamin B12 is a water-soluble vitamin absorbed in the gut and used for nerve and blood health. They do not interfere with each other's absorption, metabolism, or effectiveness.
What you should do
You can continue taking both as prescribed. You do not need to separate the doses or change the time of day you take them. Always inform your doctor or pharmacist of all supplements you are taking.
Important precautions
Pregnancy
Do not take simvastatin if you are pregnant, planning to become pregnant, or breastfeeding, as it may harm the developing baby. Use effective contraception while taking this medicine.
Muscle problems (Myopathy/Rhabdomyolysis)
Contact your doctor immediately if you experience unexplained muscle pain, tenderness, or weakness. This risk is significantly increased if you drink large amounts of grapefruit juice or take certain other medicines.
Food and drink warnings
Alcohol
It is best to avoid or strictly limit alcohol when taking simvastatin. Both alcohol and simvastatin can affect your liver; combining them increases the risk of liver damage and may also increase the risk of muscle side effects.
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.
Grapefruit and Grapefruit Juice
You must avoid eating grapefruit or drinking grapefruit juice while taking simvastatin. Grapefruit contains compounds that increase the level of simvastatin in your blood, which significantly increases your risk of serious side effects, such as muscle damage (rhabdomyolysis).
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 Sertraline and Fluoxetine together?
Taking sertraline and fluoxetine together significantly increases the risk of a rare but serious condition called serotonin syndrome. This happens because both medicines work by increasing the level of a chemical called serotonin in your brain. If levels get too high, it can cause symptoms like shivering, diarrhoea, confusion, severe muscle tightness, fever, and even seizures. Additionally, fluoxetine can slow down how your body breaks down sertraline, leading to a build-up of the drug in your system and increasing the risk of side effects.

Drug interactions checker
Can I take Biotin and Vitamin D together?
There is no known harmful interaction between biotin (Vitamin B7) and Vitamin D. It is generally safe to take these two supplements together.
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.