I started testosterone therapy 20 months after my surgery. Looking back, I was probably hypogonadal for several years prior to surgery. I thought all the fatigue was caused by my low B12 and my PCP never tested my T level. Shame on him! I injected daily with only 0.07 mg. Small diabetic needle delivers just under the skin. This avoids the extreme highs and lows of bi-weekly or monthly injections. My Uro suggested this smaller, daily dosage as he uses it for himself. Worked great. T went from 186 to 750 pretty quickly. Side effects were too extreme for me. Daily Androgel keeps my T around 550. Much more comfortable for me.