But I'm not more aggressive—a behavior change often tied to testosterone. That's not surprising to Robert Sapolsky, ., a neuroendocrinologist at Stanford University and a leading researcher on stress and behavior. "It's really not the case that testosterone 'causes' aggressive behavior," he says. "Instead, it makes the brain more sensitive to social cues that trigger aggression. And in support of that, a guy's testosterone level isn't a very good predictor of how likely he is to be aggressive."
While the adrenal glands still help out with testosterone and progesterone production in later years, the amount supplied is extremely small. The biggest issue that we see is an end to normal estrogen levels when the body converts excess testosterone into estradiol. This causes an imbalance that leads to a condition called estrogen dominance – where estrogen is now unopposed by progesterone and testosterone because their levels have declined. Estrogen dominance leads to weight gain, which further increases testosterone to estrogen conversion.