Does taking synthroid (thyroxine) daily fior hypothyroidism increase your risk for cancer? in males?

No. Synthroid (thyroxine): Simply replaces absent or inadequate thyroid hormone. It prevents you from being hypothyroid, or perhaps being overstimulated by tsh, the pituitary hormone that drive thyroid growth. There is no risk of it causing a cancer. Some would put you on it if yo had thyroid cancer, to prevent the TSH from stimulating its growth.