12–16 It can indeed protect skeletal muscle from atrophy caused by glucocorticoid treatment, obesity or aging,12,15,17 and is also beneficial when renal function is severely impaired14. Interestingly, an epidemiological study in postmenopausal women with osteoporosis showed that these patients had significantly lower levels of FGF19 compared to healthy women.18 Here, FGF19 is linked to osteoporosis.