Hello Thank you for getting in touch with us. As I see, you took Isotroin for sometime to manage your acne problem. Although it can be a cause of erectile dysfunction, it usually leads to erectile dysfunction under all conditions. In your case, you are able to get a proper erection under some circumstances while you are not able to get an erection under some other circumstances. This means that most probably, there is no pathological cause behind erectile dysfunction. Another sign which rules out a pathological cause is normal early morning erections. Therefore, we would recommend you to get in touch with your Doctor and clear out all your doubts which you feel might be interfering in your sex life. Hope this helps Regards Dr. Gagandeep Dhillon