I have spent most of this evening doing research on this subject. Over the past few weeks this has been on my mind allot, it would seem allot of cases could be explained by this (everything from primary hypogonadism, propscar/propecia usuage, anabolic steriod abuse, etc). Low libido/sexual desire, ED, PE and delayed ejaculation are all linked with low thyoird hormones. When one get's low thyroid hormones the offset of this is over-stressed adrenals, sometimes resulting in adrenal fatigue. I thought back to when i was a very young child (maybe 5+) and recall getting super hard erections that could cut through glass! At the age you haven't really developed at all, your testicles are still small and you aren't pumping out T like nobodys business. However you are still getting hard wood, so surely T/E2 isn't all to blame here? The more i thought about the more it made sense. Estridol and Thyroid hormone fight for the same receptor sites/cells, so why do you men with high E2 get ED and other problems? Why are products like derma working so well for some guy's here? The answer could be as simple as freeing up E2 (by lowering it) which is resulting in thyroid hormoene getting a chance todo it's job properly. Esso for example described getting "larger balls" and better "hang" from his penis, which would make sense since thyroid improves circulation. Both of which help with erections. Some websites worth visiting: http://www.boomersmakingadifference.com/2007/02/thyroid_problem.html http://sciencedaily.healthology.com/thyroid-health/article3876.htm I thought it would be worth posting this quote: "Once the men with hyperthyroidism were treated, almost all saw their symptoms of erectile dysfunction disappear."