What Is the HPA Axis and Why It Could Be the Hidden Link Behind Your Hormone Imbalance

If you're a woman over 40 and feeling off, you’re not alone.

Maybe you’ve said things like:
“I used to have more energy.”
“My sleep is a mess.”
“I feel wired but tired all the time.”
“I’m gaining weight even though I haven’t changed how I eat.”
“My moods feel unpredictable and not like me.”

You may have been told this is just “part of getting older.” But there's a deeper system at play here, and it’s one most women have never heard of: the HPA Axis.

The HPA Axis stands for the Hypothalamic-Pituitary-Adrenal axis. It’s a complex communication system between your brain (specifically your hypothalamus and pituitary gland) and your adrenal glands.

Think of it as your body’s central stress response system, regulating how your body responds to everything from mental stress to blood sugar fluctuations to inflammation. It also plays a major role in energy, sleep, blood pressure, blood sugar, digestion, and you guessed it—hormone balance.

As we enter midlife, our sex hormones (like estrogen and progesterone) begin to fluctuate and eventually decline. But here’s what most women don’t realize: when ovarian hormone production slows down, the adrenal glands pick up some of the slack especially when it comes to making estrogen precursors and managing cortisol.

But if your adrenals are already stressed or dysregulated, aka your HPA Axis is out of balance, your body is going to struggle. You may notice symptoms like: