Shifting Hormones in Teens: What Is Normal and When to See a Doctor?

Shifting hormones are responsible for the physical and emotional changes that develop during puberty and teenage years. Puberty can be both exciting and challenging for teenagers and their parents. It is important to know what changes are considered “normal” and when to seek medical advice.

Key takeaways:
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    Shifting hormones mark the end of childhood and the beginning of teenage years.
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    There are normal physical and psychological changes during this time.
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    Medical advice should be sought in case of early puberty, late puberty, excessive emotional issues, and if new physical or psychological issues develop.

The surge in hormones that starts the cascade of physical changes known as puberty begins before the teenage years and continues during adolescence. Adolescence (teen years) is the period of physical, cognitive, and social maturation between childhood and adulthood. Dramatic changes in hormone levels lead to changes in physical appearance, including physical growth and the development of secondary sexual characteristics. In addition, teenagers also encounter challenges in social and academic environments. The end of adolescence is considered to be when a person exhibits adult-like behavior, by which time puberty is also completed.

Hormones during puberty

During puberty, children go through physical changes to reach sexual maturity and become able to reproduce.

Puberty begins when the hormone called gonadotropin-releasing hormone (GnRH) is produced in an area of the brain called the hypothalamus. GnRH sends signals to the pituitary gland (an endocrine gland also located in the brain), which releases two major hormones: follicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH and LH stimulate ovaries and testes and trigger the release of sex hormones – testosterone and estrogen. All of these hormones are key players in the physical and emotional development experienced during puberty and teenage years.

Normal changes during puberty for boys

For boys, puberty starts sometimes between the age of 9 and 14, and doctors use a tool called Tanner stages to evaluate physical changes:

Stage 1 (the prepuberal phase): There are no noticeable changes.

Stage 2: Marked by physical changes, particularly the growth of testicles, the scrotum, and the hair around the genitals and underarms. The teenager also grows at a rate of approximately 2–2.5 inches per year.

Stage 3: The growth accelerates. The genitals continue to grow and “wet dreams” occur. The pubic hair becomes darker and takes the characteristic triangle shape, muscle mass increases, and the voice starts to change. Boys grow about 2 ¾ to 3 inches per year during this time.

Stage 4: The genitals and body hair continue to grow. Height increases approximately 4 inches per year. Some boys develop acne during this time.

Stage 5: End of puberty, when the physical development and growth are completed for most boys; usually by age 17.

Psychologically, the surge of testosterone may cause changes in behavior: mood changes, emotional outbursts, and increased arguments with the family.

Normal changes during puberty for girls

In girls, puberty starts earlier, between age 8 and 13. Similarly to boys, they also go through the Tanner stages:

Stage 1 (the prepuberal stage): There are no visible changes.

Stage 2: Breasts start to bud, some pubic hair grows, and girls typically grow approximately 2 ¾ inches per year.

Stage 3: The breasts continue to bud and more hair grows in the pubic area and underarms. Girls grow approximately 3 inches per year. Some girls develop acne during this stage and the next stage.

Stage 4: Breasts and pubic hair continue to grow, and the first menarche (menstrual period) occurs around age 12. They grow approximately 2 ¾ inches per year. Before the first period, the girls also have an increase in hip size and often experience clear or white vaginal secretions.

Stage 5: Growth and development ends for most girls, around age 16.

Changes in estrogen and progesterone levels that occur cyclically can cause emotional changes. Like boys, girls may also become more moody or have emotional outbursts.

When to seek medical attention

While not every child will go through puberty at the same time, medical advice should be sought in the following situations:

Early puberty. For girls, puberty before the 8th birthday can be due to several factors, including exposure to estrogen (for example, estrogen cream), early hormonal release from the pituitary gland, or possibly a tumor arising from the adrenal gland. For boys, early puberty is considered before age 9 and may be due to certain neurological issues or problems with the pituitary gland or thyroid gland. Signs of early puberty include physical changes that occur too quickly or not in the usual order, such as having menses before the breasts are developed in girls.

Late puberty. This should be evaluated to rule out hormonal imbalances. In teenage girls, eating disorders could also be a cause. In some cases, teenagers are simply late bloomers. Starting puberty later than normal or not progressing according to Tanner's stages suggests delayed puberty.

If the mood swings and emotional outbursts are not self-limited. If the teen’s moodiness escalates, if they become violent, or experience anxiety, depression, or other psychological issues, medical or psychological advice, and counseling can help improve the mood and ease the symptoms. Significant changes in the sleep pattern, performance at school, or alcohol or drug abuse are also red flags that a teenager needs additional support.

If new symptoms – related or unrelated to puberty – develop during this time. For example, muscle and joint pain may develop in growing children. New onset of headaches, pain in the pelvic area, or significant changes in weight should all be assessed by a doctor.