When is Puberty Too Early? (Ep. 173)

So I'm gonna start there.

When we think about puberty, we tend to put everything into one bucket.

Body odor, pubic hair, acne, breast development, growth spurts.

periods, a deeper voice.

But there are two different hormone systems responsible for these changes, and they turn on at different times.

The first one has a name you probably don't need to remember or know, and it's called adrenarche.

That's related to your adrenal glands, which are those little glands that sit on top of your kidneys.

At some point during childhood, usually age six to eight, the adrenal glands start producing increasing amounts of hormones called androgens.

And those hormones cause some very puberty-looking things like body odor, oily skin, acne, hair under the arms.

So my seven-year-old patient with a few pubic hairs and some acne, those mean her adrenal glands started doing what adrenal glands are supposed to do.

And here's the important part.

Adrenarche is not the same thing as true puberty.

True puberty starts somewhere totally different.

So where? It starts in the brain.

Did you think I was going to say gonads? Everybody loves that word.

There's a tiny area in the brain called the hypothalamus.

And at some point, it decides, okay, it's go time.

it starts releasing a hormone called GNRH in little pulses.

And those pulses go to the pituitary gland, which releases a few other hormones, namely luteinizing hormone and follicle-stimulating hormone, or LH and FSH.

And those hormones go through the bloodstream to the ovaries or the testicles.

Yeah, those go to the gonads.

In girls, the ovaries start producing estrogen, and in boys, the testicles start producing testosterone.

And that is the hormone system that drives what we think of as true puberty.

In girls, the first signs you're going to see are breast development, so that is more worrisome than hair or oiliness in a young child.

And in boys, we see enlargement of the testicles, which understandably is hard to notice by some parents because, oh my God, let me tell you, endocrinologists, they do measure the testicular size.