Originally posted by StiltmanFTW
No, I don't think so. It doesn't work like his Belt of Strength or anything. Striking power is better with Mjolnir of course (obviously, hitting with an indestructible mallet will do more damage than with your fists), but he doesn't suffer any physical attributes nerfs while not equipping it. Thor even calls the hammer "just a tool".
I have a tool as well.