Having Good thyroid hormone activity is necessary for testicular hormone production.
Low thyroid hormone activity often results in insulin resistance.
If you have hypothyroidism your body may become resistant to insulin. The Insulin resistance caused by hypothyroidism may be what has caused the reduction in Testosterone for some of us.
ezinearticles.com/?Hypothyroidis … &id=730898
Insulin resistance interferes with LH production and may also directly reduce testicular testosterone production.
Increasing Insulin Resistance Is Associated with a Decrease in Leydig Cell Testosterone Secretion in Men