The good news is that treating hypothyroidism or hyperthyroidism will usually reverse the ED. Typically, doctors say that within six months of treatment, ED may spontaneously resolve. If the ED is not relieved after six months, then treatments should be pursued.
The results were reported in a study, which found that 79% of men with thyroid dysfunction some degree of ED (52% of the men with hypothyroidism and 27% of the men with hyperthyroidism.) Severe ED was found in almost 38.% of the men with hypothyroidism and 29.6% of the men with hyperthyroidism. In general, ED was found in a significantly larger number of patients with hyperthyroidism (71%) and hypothyroidism (85%) as compared with controls (25%). After thyroid treatment to restore levels to normal, 30% of the patients had ED, a rate similar to that of a control group without thyroid problems.
Krassas, GE et. al. “Erectile dysfunction in patients with hyper and hypothyroidism: how common and should we treat? ” Journal of Clinical Endocrinology and Metabolism (Volume 93 Issue 5, pages 1815-1819). Pubmed citation