While low testosterone can cause erectile issues, please check that there is no prostate cancer by having a blood test done (PSA). Treatment for prostate cancer includes an injection which blocks testosterone, along with receiving radiation, unless surgery is recommended. Thankfully, prostate cancer is usually caught with the blood test, so early treatment is available. However, one "cured", it may take a while for the testosterone to increase. A testosterone supplement to help with ED may not be an option, as the testosterone can increase prostate cancer to re-occur. Something to consider. Good luck.