SHR # 2525 :: The Effects of Testosterone on the Physiological Response to Social and Somatic Stressors PLUS Listener Question About Vitamin D - Adam Lamb - Previous studies have shown that high testosterone levels in men decreased stress reactivity. At the same time some studies showed higher testosterone levels increased stress response. In this study they set out to apply a stress in two conditions. One with the subject alone in a room and one with an observer. The results were very interesting. PLUS Listener Christopher Price asked - what is the safest amount of D3 one can take orally, daily? Can D3 be taken intravenously, and if so, since you bypass the digestive track, does that lessen the chances of harming the kidneys?