Two years or so after your breasts start to develop, you'll probably get your first period. Periods usually last between two and eight days and come every 21 to 35 days. A 28-day cycle is common, but often it takes a while before your periods are regular.
Each month, the lining of your uterus thickens with blood to help a fertilized egg grow. When you don't become pregnant, that lining sheds, and blood comes out of your vagina. Only a couple of tablespoons of blood are released during your period, but it can seem like a lot more.
You may notice white, sticky stuff in your underpants. That's the fluid that keeps your vagina moist and clean. Vaginal discharge may become thicker and stickier at some points during your menstrual cycle. It has a slight odor but most people can't smell it. Bathing regularly with soap can help reduce the odor if it bothers you.
If your vaginal discharge becomes itchy or irritated, has a strong odor, or is dark yellow or greenish, you may have a vaginal infection. See your doctor.
Puberty brings hair to your body in new places: under your arms, in your genital area, and maybe even on your upper lip. The hair on your arms and legs may also get darker or thicker.
Pubic hair usually starts with a few straight strands and becomes curlier and darker as it grows. Eventually it grows into a thick triangle over the pubic bone and spreads a little to your inner thighs. This growth may start at the beginning of puberty or any time during it.
If you grow hair on your chest or chin, though, see your doctor. You may have a hormone imbalance that needs to be corrected.
Sweating Through Puberty
Your body starts sweating more during puberty. When sweat combines with bacteria -- under your arms, for instance -- it causes body odor. To control odor, bathe or shower every day with a deodorant soap and use an antiperspirant. "The higher the aluminum chloride content, the more antiperspirant activity it will have," says obstetrician-gynecologist Holmes. (If you develop a rash under your arms, you may be allergic to aluminum and should use an antiperspirant that doesn’t contain it.) Also, clothes made of fabrics that wick moisture will dry faster and don't show armpit stains as much.
Your feet may get sweaty too. Wear cotton socks to absorb moisture, and rotate your shoes, so they have time to dry out. Avoid shoes made of plastic, rubber, or other manmade materials. If you have sweaty palms, skip hand lotion. Use a hand sanitizer to keep your hands drier.
Acne -- whiteheads, blackheads, and pimples -- is caused by surging hormones. If you have it, try cleansing with a gentle non-soap cleanser and use over-the-counter acne products with benzoyl peroxide or salicylic acid. It also helps to use sunscreens, moisturizers, and makeup that are labeled “oil free” or “non-comedogenic.” If these things don’t get your acne under control, a dermatologist can use other treatments that will help.