You can thank folks like First Lady Michelle Obama, Madonna, and Kelly Rippa for this one. While women genetically tend to accumulate fat on the back of their arms, it takes as little as six weeks of consistent strength training to tighten your triceps and biceps and wave goodbye to batwings, according to de Mille. And don’t worry about getting man arms, as it can be really hard to pack on even a little bit of muscle; it all depends on your muscle fibers.
“If you have predominately slow-twitch muscle fibers, you're going to be a good endurance athlete, but you can pump iron until you're blue in the face and not develop noticeably defined muscles,” de Mille says. On the other hand, if you have mostly fast-twitch fibers, you can pretty much sneeze and pop a muscle. Take a look at your family to figure out what kind of fibers you likely have more of.
But even if you have the DNA of a female Arnold Schwarzenegger, it'll still be a challenge. “Women just don't have enough testosterone on board to get that bodybuilder's frame,” de Mille says. Give it time, and even if you can’t sculpt flab-free arms, chances are you will see at least a little difference.
Dress to love your shape: A flattering cap sleeve shapes the top of your arms and can help optically broaden the shoulder line to create a narrowing effect on the bottom half of the body, Raes says, making your arms look slimmer. A wider or higher neckline will also aid in this cause.