Exosome sizes decrease by about 60% in storage at 37 °C for 2 days. The size of exosomes does not change during the first two days of storage at 4 °C. However, a decrease in size is observed after 3–4 days. When exosomes are stored at −20 °C, their size remains constant over a long period. Notably, multiple cycles of deep-freezing and thawing do not affect the size of exosomes