Can I take Reishi and Royal sun 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
Both Reishi and Royal Sun (Agaricus blazei) mushrooms can thin the blood and lower blood sugar levels. Taking them together may increase the risk of bruising, bleeding, or your blood sugar dropping too low (hypoglycaemia).
Why this happens
These mushrooms have 'additive' effects. This means they work in similar ways to slow down blood clotting and improve how the body handles sugar. When combined, these effects can become much stronger than intended.
What you should do
It is usually fine to take these together, but you should monitor yourself for signs of low blood sugar (such as feeling shaky, sweaty, or dizzy) and watch for unusual bruising or bleeding. If you are scheduled for surgery or are taking prescribed blood thinners or diabetes medication, speak to your doctor before combining these supplements.
Important precautions
Bleeding disorders or surgery
These supplements may slow blood clotting and increase the risk of bleeding. You must stop taking these at least 2 weeks before any scheduled surgery. Use with caution if you are taking blood-thinning medications like warfarin or aspirin.
Diabetes
These supplements can lower blood sugar levels. If you are taking insulin or other diabetes medications, monitor your blood sugar closely as your dose may need adjustment to prevent hypoglycaemia (dangerously low blood sugar).
Auto-immune conditions (e.g., multiple sclerosis, lupus, rheumatoid arthritis)
These supplements can increase immune system activity, which may worsen the symptoms of autoimmune diseases. Avoid use if you have these conditions.
Low blood pressure (Hypotension)
Reishi may lower blood pressure. If you already have low blood pressure or take medication to control high blood pressure, they could cause your blood pressure to drop too low.
Food and drink warnings
Alcohol
It is best to avoid or strictly limit alcohol when taking medicinal mushrooms. Both alcohol and certain compounds in these mushrooms are processed by the liver; combining them may increase the strain on your liver or alter how the supplements are metabolised.
Caffeine
Reishi is often used for its calming effects, while caffeine is a stimulant. Consuming high amounts of caffeine may counteract the intended relaxing effects of the supplement.
General Food Intake
These medicinal mushrooms contain complex polysaccharides (beta-glucans). For the best absorption, it is often recommended to take them on an empty stomach, at least 30 minutes before a meal, or with a small amount of Vitamin C (such as a small glass of orange juice) which may help the body absorb the active compounds.
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 Ashwagandha and Vitamin B12 together?
There are no known clinical interactions between ashwagandha and vitamin B12. It is generally considered safe to take these two supplements together.

Drug interactions checker
Can I take Doxadura and Ginseng together?
Taking ginseng with doxazosin (Doxadura) may cause your blood pressure to drop lower than intended. This can lead to symptoms like dizziness, lightheadedness, or feeling faint, especially when standing up quickly.
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 Apixaban together?
- Can I take Anastrozole and Omeprazole together?
- Can I take Ashwagandha and Oestrogel pump-pack together?
- Can I take Ashwagandha and Vitamin B complex together?
- Can I take Bisoprolol and Fibre supplements together?
- Can I take Candesartan and Collagen together?
- Can I take Cannabis and Clarithromycin together?
- Can I take Colecalciferol and Levothyroxine together?
- Can I take Cordyceps and Reishi together?
- Can I take Devil's claw and Turmeric with black pepper together?
- Can I take Furosemide and Joint assurance together?
- Can I take Nustendi and Ramipril together?
- Can I take Pregabalin and Wellbutrin together?
- Can I take Ramipril and Vitamin D together?
- Can I take Rivaroxaban and Tamsulosin together?
- Can I take Sildenafil and Bisoprolol together?
- Can I take St John's wort and Vitamin B2 together?
- Can I take Vitamin D and Wellbutrin together?