Does Ashwagandha increase the risk of blood clots?

Ashwagandha and Blood Clot Risk

Based on current evidence, ashwagandha (Withania somnifera) does not appear to increase the risk of blood clots and may actually have mild anticoagulant properties, though this effect is not clinically significant enough to warrant concern in most patients.

Evidence on Ashwagandha's Effects on Coagulation

Safety Profile

• A randomized, placebo-controlled study in healthy volunteers showed no significant changes in hematological parameters after 8 weeks of ashwagandha supplementation (300 mg twice daily) 1
• No adverse events related to coagulation or bleeding were reported in this comprehensive safety assessment

Potential Anticoagulant Effects

• Some research suggests ashwagandha may actually possess mild anticoagulant properties rather than prothrombotic effects 2
• A study in rats demonstrated that ashwagandha treatment resulted in a significant increase in coagulation time, which returned to normal 7 days after stopping treatment 2

Clinical Considerations for Special Populations

Patients on Anticoagulant or Antiplatelet Therapy

• While direct evidence is limited, patients on anticoagulant medications should exercise caution with any herbal supplement
• According to the Natural Medicines Comprehensive Database, approximately 180 dietary supplements have potential interactions with warfarin, though ashwagandha is not specifically highlighted as a major concern 3
• The American College of Cardiology Foundation guidelines note that many herbal supplements can interact with antiplatelet agents like aspirin and clopidogrel 4

Patients with Increased Bleeding Risk

• For patients with pre-existing bleeding disorders or thrombocytopenia, monitoring may be warranted if ashwagandha is used, following similar precautions as with other herbal supplements 4
• Patients undergoing surgical procedures should disclose all supplement use, including ashwagandha, as a precautionary measure

Monitoring Recommendations

For patients taking ashwagandha who have:

1. Pre-existing coagulation disorders
2. Concurrent use of anticoagulants or antiplatelet agents
3. Upcoming surgical procedures

Consider:

• Establishing baseline coagulation parameters before starting therapy
• Periodic monitoring of relevant coagulation parameters
• Discontinuing ashwagandha 1-2 weeks before major surgical procedures as a precaution (similar to recommendations for many herbal supplements)

Conclusion

While ashwagandha appears to have a good safety profile regarding coagulation, the general precautions that apply to herbal supplements in patients on anticoagulant therapy should be observed. The evidence suggests ashwagandha may have mild anticoagulant rather than prothrombotic effects, but these are not clinically significant enough to warrant specific concerns about increased blood clot risk in most patients.