An exosome pellet or physiological solution comprising resuspended exosomes is provided. The exosomes are essentially free from particles having a diameter less than 20 nm or greater than 120 nm, and the exosomes comprise one or more metabolic products. The exosomes may be used to induce mitochondrial biogenesis, increase thermogenesis (browning) of subcutaneous white adipose tissue, and/or mediate other systemic effects of exercise in a mammal.