Does garlic affect blood coagulation and act as an anticoagulant (anti-coagulant)?

From the Guidelines

Garlic supplements should be used with caution in individuals taking prescription blood thinners due to their potential to increase bleeding risk. When considering the use of garlic for its health benefits, it is essential to weigh the potential risks and benefits, particularly in the context of bleeding and blood thinning. The evidence suggests that garlic contains compounds like allicin that can inhibit platelet aggregation and may enhance the effects of prescription anticoagulants 1.

Key Considerations

• Regular culinary use of garlic in cooking is generally safe for most people, even those on blood thinners.
• Concentrated garlic supplements (typically 600-1200mg daily) might increase bleeding risk when combined with anticoagulant or antiplatelet medications.
• If you're on blood thinners, consult your healthcare provider before starting garlic supplements.
• The blood-thinning effect of garlic occurs because it contains compounds that can inhibit platelet aggregation and may enhance the effects of prescription anticoagulants.
• If you notice any unusual bruising, nosebleeds, or prolonged bleeding while using garlic supplements with blood thinners, seek medical attention immediately.

Alternatives for Health Benefits

• For those wanting garlic's health benefits without potential interactions, focus on incorporating moderate amounts of fresh or cooked garlic into your regular diet rather than taking concentrated supplements.
• This approach can help minimize the risk of bleeding complications while still allowing individuals to reap the potential health benefits of garlic consumption. Some studies have shown that other substances, such as ginger and ginseng, may also have antiplatelet effects and interact with blood thinners 1. However, the most recent and highest quality study on garlic and blood thinning suggests that caution is advised when using garlic supplements with anticoagulant or antiplatelet medications 1.

From the Research

Garlic and Blood Thinning

• Garlic has been known to have antiplatelet properties, which can affect blood thinning [(2,3)].
• Studies have shown that aged garlic extract (AGE) may be safe for patients on warfarin therapy, with no evidence of increased hemorrhage 2.
• However, patients taking anticoagulants should be cautious when consuming garlic, as it may prolong bleeding time 3.
• Research suggests that garlic consumption, either as a supplement or in cooking, is unlikely to cause significant interactions with warfarin 4.

Interaction with Anticoagulants

• Garlic may interact with anticoagulants, such as warfarin, and affect blood clotting [(3,5)].
• The combination of garlic with other antiplatelet agents, such as aspirin and clopidogrel, may increase the risk of bleeding [(6,5)].
• Studies have identified several dietary supplements, including garlic, that may interact with standard anticoagulants and antiplatelet drugs 5.

Bleeding Risk

• The risk of bleeding associated with garlic consumption and anticoagulant therapy is still unclear [(2,4)].
• However, research suggests that the combination of anticoagulants and antiplatelet agents, such as aspirin, clopidogrel, and warfarin, may increase the risk of major and minor bleeding 6.