finasteride increases testosterone and estrogen by 15%. On my first two months of finasteride 1mg ED I gained 7.5lbs in 8 weeks. My body fat percentage went from 6.5% to 8%. Since it boosts your testosterone by 15% it should help with muscle gain. Say someone had a 1000ng/dl Testosterone level before propecia, after they would have a 1150ng/dl testosterone level after propecia. A 100ng/dl level increase in testosterone would automatically add 1.1lbs of lean body mass to an individual's frame. Propecia helps with muscle gain and gym performance, in the case that you would take dutasteride then you would experience a 20% increase in testosterone and estrogen instead of 15% with finasteride. Cheers!So i think that ive finally grown some balls to try finasteride.However,ever since I had a surgery 2 years ago I am skinny and I dont really do anything.I am about to go to gym but I am concerned that I wont be able to gain as much as I would without taking propecia.Has anyone here gained serious muscle mass while on finasteride?