Unlike a cortisone injection which typically provides rapid pain relief within a few days, symptom improvement following PRP therapy is more slow and subtle, but the positive effects are longer lasting when compared to cortisone.  Most patients receiving PRP notice some element of improvement between 2-6 weeks after the injection. “Good days” become more common and “bad days” become less common as time passes. Patients typically report reduced pain intensity, increased endurance, and improved strength.