Guarana extract reduced aggregation of rabbit platelets by up to 37 percent below control values and decreased platelet thromboxane formation from arachidonic acid by 78 percent below control values .
A university study in Brazil of guaraná extract showed a platelet aggregation decrease of up to 37 % of control values and a decrease of platelet thromboxane formation from arachidonic acid of up to 78 % of control values .