Human platelet lysate produced from leukoreduction filter contents enables sufficient MSC growth

• Leukoreduction filters, typically discarded after blood manufacturing, can yield sufficient platelets and plasma to produce human platelet lysate (f-hPL) for MSC expansion. • f-hPL at 10% supplementation significantly enhances MSC proliferation compared to commercial hPL (20% higher) and FBS (300% higher), while maintaining MSC quality. • The optimal protein concentration for f-hPL lysate is >27 mg/mL, and a single filter can provide ~3.5×10^10 platelets with 37.1% collection efficiency. • This approach offers a sustainable, cost-effective, and ethical alternative to FBS and commercial hPL for clinical-scale stem cell therapy.