Can I take Reishi and Royal sun together?
Drug interaction guide
Originally published 25 Jan 2026
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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.
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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
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