The present disclosure relates to the generation of an activated platelet product in which one or more of the presence or absence of clots, the timing of clot formation (if present), and/or the mechanical strength of clots (if present) is controlled by the presence or concentration of calcium ions during the activation process. In certain embodiments, the calcium ion concentration is controlled inthe presence of pulsed electric fields or a chemical activator (e.g., thrombin) as part of the activation process.