Dx 2015 APC with iliac lymph node involvement. Had RT, on lupron for 20 months, turned to CRPC seven months ago. Now on zytiga and Prednisone (5mg) for the last seven months. Had orchiectomy two months back. With zytiga, practically no side effects. I use to read all the posts in this forum for the last six months. I learn from the posts of many that they take metformin along with their other medicines even though they are not diabetic. My MO didn't prescribe metformin for me so far. I asked my GP's opinion. He told that post-orchiectomy patients may develop insulin resistance due to the defficiency of testosteron. I am not diabetic and my blood sugar is normal now. Should I take metformin? Is there any proven studies that metformin is beneficial for patients like me. If it is beneficial what is the ideal dosage for for a non diabetic person. I expect a good advice from my fellow-members who got very wise opinions regarding all the treatment regimes.