Brown adipose tissue (BAT) is known to contribute to daily energy expenditure via the process of adaptive thermogenesis. The primary physiological regulator of BAT is exposure to ambient cold. In addition to its effects on energy expenditure, activation of brown adipose tissue has been associated with increased glucose and triglyceride clearance as well as improved insulin sensitivity. Despite this, few studies have addressed the mechanisms by which BAT activity is regulated in humans. Numerous animal studies have demonstrated that estrogen acts within the brain to regulate both reproductive and metabolic functions, in particular estrogen increases thermogenesis via activation of the sympathetic nervous system. Furthermore, in young healthy participants we have previously demonstrated that the degree of BAT activation in response to physiological stimuli is correlated with plasma concentrations of 17β-estradiol. However, it remains unknown as to whether exogenous ovarian steroids in the form of hormonal contraceptives (combined oral contraceptives and progestin only based contraceptives) can influence BAT activity and metabolic function. It also remains unknown as to whether menthol, a cold mimetic, can be used to increase BAT activity. We have used infrared thermography to measure changes in supraclavicular temperature (index of BAT activity). This presentation will describe the effects of hormonal contraceptives in women as well as sub-chronic menthol treatment in men on BAT heat production and glucose metabolism.