Arm workout for slimmer arms in 6 weeks, going to give it a try! Leave a Comment / Beauty Tips, Women's Fashion / By admin Sexy Arms in 6 Weeks If you’re just starting out, aim for two sets of 8 to 12 reps of the heaviest weight you can handle for each exercise. Looking for more of a challenge? Shoot for two sets of 15 to 25 reps per exercise.