I would like to recommend that you watch this talk given last month at the A4m (American Academy of Anti-Aging Medicine).
In it, Dr. Duncan Ross, founder of Kimera Labs, explains how he discovered the power of exosomes. He also explains what makes young exosomes so different from older ones.
Quality control issues are addressed and the standards for safe production of exosomes are explained.
Finally, current good standing of his lab and their path towards FDA approval is explained.