How Mold Messes with Your Thyroid (and Might Be Behind Your Hashimoto’s)

Mold and mycotoxins can quietly wreak havoc on thyroid function, sometimes before ever raising your antibodies. When I was trying to figure out what was wrong with me, I first zeroed in on my thyroid and hoped that increasing my thyroid meds would make me feel human again. Well, that backfired spectacularly and made me feel even worse. After a lot of digging (if you've seen my TikTok, you know what I'm talking about), I finally came to the conclusion that mold was at the center of all my symptoms (and likely triggered autoimmunity). This is why I have a whole section in my Back to Balance course about how toxins (like mycotoxins from mold) can be a key player in Hashimoto's and thyroid dysfunction.

So how does mold cause such chaos in your thyroid?

Mold disrupts your hormone signaling

• Mycotoxins are neurotoxic (they mess with your brain) plus endocrine disrupting (they mess with your hormones).

• They create a ton of inflammation, which affects your hypothalamus and pituitary - those are the parts of the brain that coordinate TSH release (the signal to your thyroid to make thyroid hormones).

• So even if your thyroid gland is trying to do its job, the signals are messed up.

• You might see “normal” TSH but still feel like trash because downstream hormones aren’t converting well or they aren't being used efficiently.

Clinical clue: You feel hypothyroid, but labs don’t fully match, or numbers fluctuate wildly.

Mold destroys gut function

• Mold can trigger gut dysbiosis, candida overgrowth, & leaky gut.

• Most of your T4 to T3 conversion happens in the liver & gut, so gut dysfunction means there are lower amounts of the active thyroid hormone for your cells to use.

• The damage to the gut means nutrient absorption tanks. You lose iron, selenium, zinc, and iodine, which are all key players in thyroid health.

• Gut damage can lead to immune dysregulation, which can trigger Hashimoto’s.

• Inflammation in the gut plus the decreased nutrient absorption can mean low levels of DAO, the enzyme that breaks down histamine. That triggers a vicious circle of inflammation without resolution and a whole host of symptoms that we may think are thyroid related but turn out to be caused by histamine.

Clinical clue: Thyroid symptoms + gut stuff (bloating, IBS, food sensitivities) = red flag for mold.

Mold slows liver detox & hormone conversion

• Your liver converts T4 → T3. It also clears excess hormones, including estrogen.

• Mold toxins overload Phase I and Phase II detox pathways in the liver, clog bile flow, and trigger oxidative stress.

• Impaired bile flow also means poor clearance of used-up hormones, which can cause estrogen dominance, making thyroid symptoms worse.

Clinical clue: Low T3, sluggish detox markers (e.g. high ALT/AST, low bilirubin), or poor response to thyroid meds.

Mold depletes key nutrients

• Mold exposure increases demand for antioxidants and minerals used in detox (especially zinc, selenium, magnesium, B vitamins, which are incredibly important for thyroid health).

• You also lose stomach acid, which makes nutrient absorption worse.

• Over time, you can’t make or convert thyroid hormones properly, even if you’re taking medication.

Clinical clue: You’re supplementing but not seeing results, or you feel worse when taking methylated B’s or iron.

Mold jacks up your stress response

• Mold dysregulates your HPA axis, leading to cortisol spikes & crashes, insomnia, and nervous system dysfunction.

• Chronic stress suppresses TSH, impairs T4→T3 conversion, and increases reverse T3 (the inactive “brake” hormone that blocks your actual thyroid hormones from working).

• Also disrupts sleep and blood sugar, which affect thyroid function too.

Clinical clue: Wired and tired. Palpitations. Crashes after eating. Trouble falling or staying asleep.

How to test for mold

• If you know or suspect that you are affected by mold, the easiest first step is to do the VCS test. Details in this post will walk you through it.

• Doing a urine mycotoxin test or organic acids test can help you see if you're body has mycotoxins to deal with.

• Checking your adrenal function and sex hormones to see how they're doing is also a good idea, as well as a GI Map if gut issues are involved.

If you'd like information about running any of the tests mentioned, reach out here and I can help you get them ordered and give you a gameplan based on your results.

What to do:

Step one is connecting the dots. If mold exposure is part of your story (or even a suspicion), your thyroid won’t fully stabilize until you address the root.

That’s why I include mold and toxin support inside my Back to Balance program. It covers recognizing and healing from the top 6 root causes of Hashimoto's. Figuring out your unique combo of root causes (because there are usually more than one wreaking havoc at any given time) is key to calming your autoimmunity.

I'm currently moving Back to Balance to a new platform to make the whole experience so much smoother. Keep an eye out for the relaunch! You may want to join my mailing list here if you're interested in helping me test out the new platform at a crazy good price (you'll also get a free mocktail guide just for joining the list).

If you like what you’re learning here, you’ll love the conversations happening inside my free Facebook group, Find Your Balance. Come join us!

Disclaimer: I do not diagnose, treat, prevent, or cure any disease or condition. Nothing I share with my clients is intended to substitute for the advice, treatment or diagnosis of a qualified licensed physician. I may not make any medical diagnoses or claim, nor substitute for your personal physician’s care. It is my role to partner with you to provide ongoing support and accountability in an opt-in model of self-care and any changes should be done under the supervision of a licensed physician.