When most people think of puberty, the teenage years come to mind. This period, which generally happens between ages 8 and 14, is when you develop from a kid into an adult. Your body goes through many physical changes during this time.

But after puberty, your body continues to change. This is a natural part of aging. These age-related changes are sometimes called “second puberty.”

It’s not an actual puberty, though. Second puberty is just a slang term that refers to the way your body changes in adulthood.

The term can be misleading, since you don’t actually go through another puberty after adolescence.

In this article, we’ll explain what people mean when they talk about second puberty and what it looks like throughout life.

Since second puberty isn’t a medical term, there isn’t an official definition that describes when it occurs.

But the changes in your body that the slang term refers to can take place during your 20s, 30s, and 40s.

It’s important to note that people use the word in different ways. When they say second puberty, they might mean:

  • one decade of life, like your 30s
  • the transition from one decade to another, like your late 20s and early 30s

In men, here’s what second puberty may look like.

In your 20s

During this time, you continue to physically mature as you transition out of your teenage years. This includes physical changes like:

  • Maximum bone mass. You achieve your peak bone mass, which is the most bone tissue you’ll have in life.
  • Maximum muscle mass. Your muscle also reaches its peak mass and strength.
  • Slowing prostate growth. During puberty, your prostate grows quickly. But at age 20, it starts to grow very slowly.

In your 30s

By your mid-30s, your testosterone levels gradually decrease. However, this won’t cause noticeable signs.

The physical changes you do experience are usually associated with aging in general. These may include:

  • Declining bone mass. Your bone mass slowly decreases in your mid- or late 30s.
  • Declining muscle mass. You begin to lose muscle mass.
  • Changing skin. You may develop wrinkles or age spots in your late 30s.
  • Graying hair. After your mid-30s, you’re more likely to develop gray hair.

In your 40s

The changes that occur in your 30s continue into your 40s.

At the same time, physical changes due to decreasing testosterone will become more noticeable. These changes are known as male menopause or andropause.

You can expect:

  • Fat redistribution. Fat may accumulate in your belly or chest.
  • Declining height. In your spine, the discs between your vertebrae begin to shrink. You may lose 1 to 2 inches in height.
  • Growing prostate. Your prostate goes through another growth spurt. This might make it difficult to urinate.
  • Erectile dysfunction. As testosterone decreases, it becomes more difficult to maintain an erection.

Second puberty in women involves a wide range of physical changes. Here’s what you can expect.

In your 20s

As a young woman, your body continues to grow and mature. You typically reach your peak physical ability during this time.

Physical changes include:

  • Maximum bone mass. Your body reaches its peak bone mass in your 20s.
  • Maximum muscle strength. Like males, your muscles are strongest during this time.
  • Regular periods. Your estrogen levels peak in your mid or late 20s, causing predictable periods.

In your 30s

Second puberty in your 30s refers to perimenopause, or the transition into menopause. It can start in your mid- or late 30s.

Irregular estrogen levels cause the physical changes of perimenopause. These changes include:

  • Declining bone mass. Your bone mass begins to decrease.
  • Declining muscle mass. You’ll also begin to lose muscle mass.
  • Changing skin. As your skin loses elasticity, you may develop wrinkles and sagging skin.
  • Graying hair. Some of your hair might turn gray.
  • Irregular periods. By your late 30s, your periods become less regular. Your fertility also decreases.
  • Vaginal dryness. The lining of your vagina becomes drier and thinner.
  • Hot flashes. A hot flash, or an abrupt feeling of heat, is a common sign of perimenopause.

In your 40s

In your early 40s, the physical changes from the previous decade continue.

But by your late 40s, your body will start to enter menopause. Some people call this transition a second puberty.

Menopause causes changes like:

  • More rapid bone loss. Once you reach menopause, you’ll lose bone more quickly.
  • Decreasing height. Like men, women lose height as the discs between their vertebrae get smaller.
  • Weight gain. Your body changes the way it uses energy, which makes you more prone to weight gain.
  • Irregular or no periods. As your body makes less estrogen, your periods become even more irregular. Your periods will likely stop by your early 50s.

Like puberty in adolescence, you can’t stop the changes in your body from happening.

That’s because second puberty involves the natural aging process. These changes are a normal part of getting older.

While you can’t avoid the changes that come with aging, you can get ready for them.

The key is to practice healthy habits throughout life. This will help you prepare for these changes, both physically and mentally.

Examples of healthy habits include:

  • Staying active. Exercising regularly throughout adulthood will help slow down bone and muscle loss. A routine that involves both cardio and strength training is best.
  • Eating well. Consuming a diet rich in fruits, vegetables, whole grains, and lean meats is essential for healthy aging.
  • Managing chronic diseases. If you have a chronic condition, work with a doctor to manage it. This will prevent complications as you age.
  • Attending regular health checkups. By regularly seeing a doctor, you can get appropriate guidance during each stage of life. This includes checkups with a primary care doctor and other specialists, like a gynecologist.

Second puberty isn’t a real medical term. People use it to describe how your body changes during your 20s, 30s, and 40s.

The term can be misleading, as these changes are different from puberty during adolescence.

Many age-related changes are due to declining hormone levels over time. To prepare for these natural changes, follow a healthy lifestyle and stay on top of your routine health checkups.