The Hidden Link Between Stress, Cortisol, and Your Thyroid
You’re tired — but wired. You crash in the afternoon but can’t fall asleep at night. You wake up groggy no matter how long you sleep.
Sound familiar? For many women, stress isn’t just an emotional burden — it’s a biological disruptor. And one of the first systems it hijacks? Your thyroid.
Let’s unpack how stress and cortisol imbalance could be keeping you stuck — and what you can do about it.
Cortisol: Your Survival Hormone
Cortisol is your body’s main stress hormone. It’s meant to help you survive short bursts of danger — not long-term overwhelm.
But when you're constantly "on" (hello, demanding job, caregiving, chronic illness, or all of the above), your cortisol rhythm shifts… and everything else gets thrown off.
When cortisol stays high (or crashes from burnout), it can:
Disrupt thyroid hormone conversion (T4 to T3)
Suppress TSH (your brain’s signal to the thyroid)
Increase reverse T3 (an inactive, blocking hormone)
Drive up inflammation and autoimmunity flare-ups
Yes — chronic stress can actually slow your metabolism, increase fatigue, and aggravate Hashimoto’s symptoms.
Your Thyroid and Adrenals Talk to Each Other
Your thyroid and adrenal glands work in a delicate partnership.
If one is overworked, the other often suffers.
🚫 Conventional medicine tends to treat these separately (or overlook adrenal health entirely).
✅ Functional nutrition looks at how these systems are connected — especially for women experiencing burnout, anxiety, or that “always tired but can’t rest” feeling.
How I Spot Cortisol Imbalance in My Clients
At Mariposa FNC, I listen for the signs cortisol is dysregulated:
Energy crashes mid-day
Trouble falling or staying asleep
Increased belly weight despite clean eating
Mood swings, irritability, or anxiety
Reliance on caffeine to "get through the day"
When needed, I use the DUTCH hormone test to look at your full cortisol pattern — not just a single number. This helps uncover when your stress response is most out of sync and how it's impacting thyroid, estrogen, and progesterone levels, too.
My Story: Stress Was the Trigger No One Caught
I'm lying on the floor next to my dad's bed in hospice. You can see the stress, grief, and heartbreak in my eyes, on my skin, and even in my hair.
Before I was diagnosed with Hashimoto’s, I was constantly in go-mode.
I was working full-time in healthcare, had just moved back to the U.S. after living overseas for nearly a decade, and was adjusting to an entirely new life. On top of that, my dad had just been diagnosed with lung cancer.
It was a lot.
I told myself I was just tired. That I needed to push through.
But the fatigue was relentless. My hair was thinning. I was gaining weight no matter what I ate. My body was clearly asking for help — but no one asked me about stress. No one looked at cortisol.
It wasn’t until I began learning about the functional nutrition connection between stress, cortisol, and thyroid function that things finally made sense. Once I started supporting my adrenals and nervous system, I finally felt like I could exhale — and begin to heal.
What You Can Do to Support Your Thyroid + Adrenals
Here’s where to start if you think stress is sabotaging your thyroid:
Get honest about your stress load — emotional, physical, environmental
Build in nervous system support daily (walks, breathwork, journaling, magnesium, rest)
Limit caffeine and sugar — they spike cortisol even more
Eat protein with every meal to stabilize blood sugar and support adrenal health
Work with someone who can run functional hormone testing (I offer DUTCH testing when appropriate)
You don’t need to live in survival mode.
Your thyroid can’t heal until your body feels safe.
And that starts with listening to your stress signals — and giving your body what it’s truly asking for.