Ligustrazin (also known as tetramethylpyrazine, TMP) is an active compound extracted from the Chinese medicinal herb Ligusticum chuanxiong. Its use for supporting or preventing blood clots is primarily derived from both traditional Chinese medicine (TCM) practice and emerging scientific research. In TCM, preparations containing ligustrazin have long been used to "invigorate blood circulation" and "remove blood stasis," concepts often interpreted as supporting cardiovascular health and reducing the risk of clot formation.

On the scientific front, there are several in vitro and animal studies suggesting that ligustrazin may have anti-platelet aggregation and anti-thrombotic effects. Some clinical studies (mainly from China) have reported that ligustrazin injections or oral formulations can reduce blood viscosity and platelet aggregation, potentially lowering the risk of thrombus formation. However, most of these studies are small, lack rigorous controls, or are published in local journals, limiting their generalizability and acceptance in mainstream medicine. Systematic reviews and meta-analyses have highlighted methodological flaws and called for higher-quality evidence.

Currently, ligustrazin is sometimes used as an adjunctive therapy in China for conditions such as ischemic stroke and coronary heart disease, but it is not widely recognized or approved for this use in Western medicine. Therefore, while there is some preliminary scientific evidence, it remains limited (rated 2 out of 5), and further high-quality randomized controlled trials are needed to confirm its efficacy and safety for blood clot prevention.