Can I take Magnesium and St john's wort together?
Drug interaction guide
Originally published 25 Jan 2026
Meets Patient’s editorial guidelines
- DownloadDownload
- Share
- Language
- Discussion
There are no known significant interactions between magnesium supplements and St John's Wort. It is generally considered safe to take these two together.
In this article:
Continue reading below
Why this happens
Magnesium and St John's Wort are processed by the body through different pathways. Magnesium is a mineral primarily regulated by the kidneys, while St John's Wort affects liver enzymes (specifically CYP3A4). They do not interfere with each other's absorption or effectiveness.
What you should do
You can take these together. However, always inform your doctor or pharmacist about all supplements you are taking, as St John's Wort interacts with many prescription medicines (such as antidepressants, blood thinners, and the contraceptive pill).
Continue reading below
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

Treatment and medication
Can I take Levothyroxine and Coffee together?
Drinking coffee at the same time as taking levothyroxine can significantly reduce the amount of medicine your body absorbs. This means your thyroid hormone levels may stay too low, and your symptoms (like tiredness or feeling cold) might not improve as they should.

Treatment and medication
Can I take Paracetamol and Ibuprofen together?
There is no harmful interaction between paracetamol and ibuprofen. In fact, they are often taken together because they work in different ways to provide better pain relief than either medicine alone.
Continue reading below
Article history
The information on this page is written and peer reviewed by qualified clinicians.
25 Jan 2026 | Originally published

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.