If you're a young woman just starting weight training, slowly lifting heavier weights over time will make your triceps (the back of your arms) grow about twice as much as just doing the same workout over and over.

Even if you lift the same weight every time without making it heavier, your arms can still get noticeably bigger in just two months — at least when you're just starting out and you're a young woman.

Even if you don’t lift heavier weights over time, just doing regular arm workouts for 8 weeks can make your triceps muscles noticeably bigger—way more than just sitting around.

When guys who work out a little bit lift heavy weights (85% of their max), their triceps muscles grow faster and more reliably than when they lift light weights (30% of their max)—so how heavy you lift might change when your muscles start getting bigger.

If you're someone who regularly lifts weights, doing more triceps exercises each week might help your triceps muscles get a little bigger—but only a little, and not as much as it helps your biceps.

This claim says that lifting lighter weights until you're tired, done regularly for six weeks, can build muscle just as well as lifting heavier weights. It specifically found growth in arm and chest muscles, showing you don't always need heavy weights to get stronger.