If you take a blood thinner, several common supplements can add to its effect and increase bleeding risk. Individually most are modest. The problem is that they add up, and people rarely mention them because supplements do not feel like medicines.
Blood thinners include warfarin, clopidogrel, aspirin taken for the heart, and the newer oral anticoagulants. Anti-inflammatories such as ibuprofen add to the same risk.
Common side effects reported with this supplement or ingredient
The effect you would notice is not a new symptom but a change in degree: bruising more easily than before, cuts bleeding longer, nosebleeds or bleeding gums appearing when they did not previously, or heavier periods. Any of these developing after starting a supplement is worth reporting.
Possible interactions with medicines, chronic conditions or pregnancy
Supplements that may add to bleeding risk:
- Fish oil and omega-3, particularly at higher doses
- Turmeric and curcumin
- Ginkgo biloba
- Garlic supplements, at concentrations well above culinary use
- Vitamin E at high doses
- Ginger and ginseng preparations
Two supplements affect warfarin differently and deserve separate mention:
- Vitamin K works against warfarin rather than with it. The aim is consistency rather than avoidance, since large swings in intake destabilise the INR in either direction.
- St John’s Wort reduces warfarin’s effect, meaning less protection against clots. See St John’s Wort interactions.
Cranberry products have also been associated with changes in warfarin effect and are worth mentioning.
Who should speak to a healthcare professional before using it?
Anyone on a blood thinner, anyone with a bleeding disorder, anyone on regular anti-inflammatories, and anyone with surgery, a dental extraction or another procedure planned.
Supplements affecting bleeding are usually stopped some days before a procedure, and the timing depends on the product. Ask well in advance rather than the day before. See supplements before surgery.
Dose, product-quality and stacking risks
Supplements in South Africa are regulated as complementary medicines, and the checks applied are not the same as those for prescription medicines. Strength and content can vary between products. See how supplements are regulated in South Africa.
Stacking is the specific danger here. A joint formula containing turmeric, a heart formula containing fish oil, and a memory formula containing ginkgo may look like three unrelated products while all pulling in the same direction. Read the ingredient panels together rather than one at a time.
When to stop and get medical advice
Get emergency help for: vomiting blood or material like coffee grounds; black tarry stools; pink, red or brown urine; coughing up blood; bleeding that will not stop with pressure; a severe or unusual headache; or any significant blow to the head, even if you feel well afterwards.
Contact your clinic if bruising or bleeding has increased since starting a supplement. If you take warfarin, mention it before your next INR, since the reading may need interpreting in that light. See warfarin side effects and bruising on blood thinners.
Stop the supplement rather than the blood thinner, and ask.
Related supplement safety guides
- Supplement side effects
- Supplement and medicine interactions
- Supplements before surgery
- Unsafe supplements in South Africa
- 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.