Several common supplements affect bleeding, blood pressure, blood sugar or sedation, all of which matter during surgery and anaesthesia. Most surgical teams ask you to stop certain supplements in advance.
Tell your surgeon, anaesthetist and pre-assessment nurse everything you take, including supplements and herbal products. This is the part most often left out, usually because supplements do not feel like medicines worth mentioning.
Common side effects reported with this supplement or ingredient
The concern is not side effects in the usual sense but effects that complicate an operation: more bleeding than expected, blood pressure that behaves unpredictably under anaesthetic, blood sugar that drops, or sedation that adds to anaesthetic drugs.
Possible interactions with medicines, chronic conditions or pregnancy
Supplements that affect bleeding: fish oil and omega-3, turmeric and curcumin, ginkgo, garlic supplements, vitamin E, ginger and ginseng. These matter more if you also take a blood thinner or anti-inflammatory. See supplements and blood thinners.
Supplements affecting blood sugar, which can complicate fasting before an operation.
Sedating supplements, including those for sleep and anxiety such as kava and valerian-type products, which add to anaesthetic and sedative drugs. See kava side effects.
St John’s Wort, which affects how a wide range of medicines are processed, including some used around surgery. See St John’s Wort interactions.
Stimulant products, including high-caffeine pre-workouts and fat burners, which affect heart rate and blood pressure.
Who should speak to a healthcare professional before using it?
Anyone with an operation, dental extraction, endoscopy or other procedure planned. Raise it at the pre-assessment appointment rather than the day before, since the advice usually involves stopping something a week or more in advance.
How far in advance depends on the supplement and the procedure, so ask rather than following a general rule. Some are stopped around a week or two before; others matter less.
Dose, product-quality and stacking risks
Take the actual products to your pre-assessment appointment, or photograph the ingredient panels. Combination formulas frequently contain several relevant ingredients, and the product name rarely reveals them.
Do not apply this reasoning to prescribed medicines. Some are stopped before surgery and some must be continued, and stopping the wrong one causes more harm than any supplement would. That decision belongs to your surgical team. See should I stop my chronic medication.
When to stop and get medical advice
Tell your team, do not simply cancel or stay silent, if you forgot to stop something, took a dose closer to the operation than advised, or take something you did not previously mention. Anaesthetists would far rather know late than not at all, and it may change nothing.
Afterwards, ask when it is appropriate to restart, particularly for anything affecting bleeding while a wound is healing.
Related supplement safety guides
- Supplement side effects
- Supplement and medicine interactions
- How to check supplement labels
- When to see a doctor about a supplement
- Report a supplement side effect
Medical Disclaimer: This content is for informational and educational purposes only and does not constitute medical diagnosis, prescription, or professional advice. Always read the patient information leaflet and consult a qualified doctor or pharmacist regarding any medicine or health concern.