Androgen therapy is the mainstay of treatment in female to male (FtM) transgender persons to increase testosterone levels, suppress oestrogens and treat gender dysphoria. Testosterone is widely used for male hypogonadism, but is comparatively under-investigated in FtM transgender persons. The aim of our study was to identify treatment and safety outcomes associated with testosterone use in transgender medicine. Androgens in FtM transgender persons are effective to lower voice frequency, increase facial hair-growth, and increase hematocrit and hemoglobin levels to adult male reference ranges. A 1.2-fold-3.7-fold higher rate of myocardial infarction has been reported retrospectively, compared to cisgender women. Blood pressure, glycaemic control and body mass index remained unchanged in FtM transgender persons. Androgens in FtM transgender persons have important cardio-metabolic implications. Randomised control trials, longer follow-up periods and studies involving older persons may further improve the management of FtM transgender persons.