Muscles
When you’re very young, your arms, legs, and body might look a lot like those of a girl sitting next to you in class. When puberty hits, this will change. Slowly, you’ll start gaining more muscle in your arms and legs, your shoulders, and pretty much all over. You won’t look like a body-builder overnight, and each guy will grow muscles at his own rate.

It’s important not to rush things. Don’t start lifting weights every day or trying other ways to “bulk-up” before your body is ready. Give yourself a chance to grow into your body.

A note about breasts: During puberty, some guys notice that their chest or nipples seem swollen or tender, or that they’re starting to, uh, grow in that area. This happens to a lot of people. It’s caused by all the hormones in your body and it’s TEMPORARY. Try not to panic: you are not actually growing breasts. It will most likely go away soon.

Hair
Everybody gets hairier as they go through puberty, and it’s totally natural. Sometimes, growing hair where you used to have none is one of the first signs that you’re starting puberty.

• Face facts: As you go through puberty, you might start to grow hair on your face. This usually starts with a soft, thin mustache on your upper lip. This hair will grow thicker as you get older. Your beard, which is the hair on your cheeks, chin, and neck, may also start to come in.

• The pits: As puberty starts, you’ll begin growing hair underneath your arms. It will probably be light and soft at first, but will get thicker as you get older.

• Down below: You’ll also start growing hair between your legs, above and around your penis, and on your scrotum (the sack of skin that holds your testicles). This is called pubic hair, because the area between your legs is called your pubis. Again, this hair will grow gradually, getting thicker as you get older. It usually gets curlier and darker as you grow up.

• Arms and legs: Almost everybody has hair on their arms and legs. When you’re a kid, this hair is hard to see, because it’s so soft and light. During puberty, it’ll probably grow thicker and darker.

• Other places: Towards the end of puberty, usually in the teen years, some guys may start growing hair on their chest, back, or rear end. Most of the time this has more to do with genes you inherit from your parents than it does with puberty. Some guys don’t grow hair in these places until many years later, and some don’t grow it at all.

• Color questions: The color and thickness of the body hair you grow during puberty will depend on a lot of things. If you have dark hair on your head, your body hair may also be dark, so that it’s more visible. If you have very light blonde hair on your head, you may have very light and blonde body hair, but not always. Sometimes, blonde guys grow underarm hair or pubic hair that’s brown. Your facial hair can also be a slightly different color from the hair on your head. This may make you feel a little “mismatched” but it is normal!

• The No-Hair Scare: It’s important to remember that each guy who’s going through puberty will grow face and body hair on a different schedule, and it’s not a race to see who can grow the most hair the soonest. One kid might seem very hairy in middle school, while his friend remains smooth until high school. Another kid might have plenty of underarm hair at 15, but no beard or mustache until he’s 20.

Some guys are happy when they start to grow a mustache or get body hair, because they’ll look more “manly”, but it’s okay to not be so thrilled about it. If you don’t like the look or feel of facial hair, you can talk to a parent about shaving with shaving cream and a razor, or with an electric razor. Keep in mind that once you start shaving, the hair will usually grow back a little thicker and tougher than the hair that grew first.

Next: The Down-Low on Voice Changes