Hashimoto’s doesn’t typically cause high cortisol in most people. The evidence is genuinely mixed. Some studies show cortisol going up, others show it going down, and the direction depends on your immune profile, your stress load, and how active the disease is.
What’s far more clinically important is the opposite problem: low cortisol, especially if you have Hashimoto’s alongside undiagnosed adrenal failure. Starting thyroid hormone replacement without checking for adrenal insufficiency first can trigger a crisis within days. That’s the real story here.
Is High Cortisol Common With Hashimoto’s?
Not really. One study of 40 women with Hashimoto’s found morning cortisol levels were significantly higher than in healthy controls, with every 1 ng/mL rise in cortisol linked to a 19% higher odds of having the condition.
But a separate study of 37 Hashimoto’s patients found the opposite. Their cortisol levels were meaningfully lower than controls (13.5 vs 16.0 µg/dL), alongside elevated prolactin and widespread autoantibody activity.
These two studies point in opposite directions. That’s not a flaw in the research, it reflects something real. Cortisol levels in Hashimoto’s are not fixed. They shift depending on how active the autoimmune process is, how stressed you are, and whether other conditions are running alongside it.
In my experience working with people managing thyroid conditions, the cortisol question comes up constantly. Most people asking “do I have high cortisol?” are actually describing symptoms of low cortisol: crushing fatigue, dizziness when standing, salt cravings, and a feeling that nothing is recovering. That matters clinically, and it matters practically.
What Hormone Is Elevated in Hashimoto’s?
The most consistently elevated hormones in Hashimoto’s are thyroid-stimulating hormone (TSH) and thyroid peroxidase antibodies (TPO-Ab). As the immune system attacks thyroid tissue, the pituitary gland pumps out more TSH trying to drive a gland that can no longer keep up. That’s why TSH is the primary screening marker.
Prolactin is also commonly elevated, as shown in. High prolactin can cause fatigue, menstrual irregularities, and reduced libido, symptoms that often get blamed on the thyroid when the prolactin connection is missed.
Cortisol is not reliably elevated in Hashimoto’s as a direct result of the disease. Where cortisol does rise, it’s more likely driven by chronic psychological or physiological stress activating the HPA axis, the system that runs from your hypothalamus through your pituitary to your adrenal glands, rather than the autoimmune process itself.
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How Stress and the Immune System Talk to Each Other
When you’re chronically stressed, your HPA axis stays activated. That means sustained cortisol output and elevated catecholamines like adrenaline. Over time, this shifts your immune system away from Th1 responses, the kind that drive cellular immunity, toward Th2 responses, which drive antibody production.
This matters for thyroid autoimmunity because Hashimoto’s is largely Th1-driven, while Graves’ disease (the overactive thyroid autoimmune condition) is more Th2-driven. Chronic stress may influence which of these conditions develops or how aggressively it progresses.
There’s another layer here. Corticotropin-releasing hormone (CRH), the signal your hypothalamus sends to kick off cortisol production, also acts directly at immune sites in the body and has pro-inflammatory effects. So the stress-cortisol-inflammation loop isn’t simple. Raising cortisol doesn’t cleanly reduce inflammation in autoimmune thyroid disease the way a corticosteroid drug might.
One of my clients spent two years assuming her fatigue was purely thyroid-related. Her TSH was optimised, her T4 and T3 were in range, but she still felt terrible. When we pushed to investigate her adrenal function, her cortisol response was blunted. No one had looked. She wasn’t in crisis, but she was running on empty because the stress load from years of undertreated autoimmune disease had worn down her adrenal reserve.
Do Thyroid Issues Cause High Cortisol?
Thyroid dysfunction and cortisol are tightly linked, but the relationship runs both ways. Hypothyroidism, which is the end-state of untreated Hashimoto’s, can slow cortisol clearance from the body, meaning cortisol stays in circulation longer. That can look like high cortisol on a test even when production is normal. It doesn’t mean your adrenal glands are overproducing.
The more clinically significant direction is this: starting thyroid hormone replacement speeds up your metabolism. That increases how fast cortisol is cleared from your body. If your adrenal glands are healthy, they simply make more. If they’re not, if autoimmune damage has already reduced their output, that increased demand can push you into adrenal insufficiency fast.
This is where the danger lives. Not in Hashimoto’s raising cortisol, but in Hashimoto’s treatment exposing a cortisol problem that was already there.
The Real Risk: Hashimoto’s and Addison’s Disease Together
Autoimmune diseases tend to cluster. If your immune system is already attacking your thyroid, the risk that it’s also targeting other glands, including your adrenal glands, is higher than average. When Hashimoto’s and Addison’s disease (primary adrenal insufficiency) occur together, it’s called autoimmune polyglandular syndrome type 2, or Schmidt’s syndrome.
The numbers aren’t enormous, but the consequences of missing it are serious. Multiple documented case reports describe patients with known Hashimoto’s who went into adrenal crisis shortly after starting levothyroxine.
In one case, a 13-year-old with Hashimoto’s developed pallor, dehydration, rapid heart rate, electrolyte imbalance, and extremely low cortisol after beginning thyroid treatment. Another case presented with spontaneous hypoglycemia, the drop in blood sugar caused by cortisol deficiency unmasked when thyroid metabolism accelerated.
I remember one of my clients describing how she felt “completely destroyed” about three weeks into starting levothyroxine. Her doctor assumed it was a dosing issue and reduced her prescription. The real problem was that her adrenal glands couldn’t keep up with the metabolic demand the medication created. She eventually got the right testing and was managed appropriately, but it took months of unnecessary suffering to get there.
The mechanism is straightforward: levothyroxine raises basal metabolic rate, which raises cortisol demand. When adrenal reserves are already compromised by autoimmune destruction, that demand can’t be met, and crisis follows.
Warning Signs You Shouldn’t Ignore Before Starting Thyroid Treatment
If you have Hashimoto’s and any of the following, ask your doctor to check morning cortisol and ACTH before starting or increasing levothyroxine:
- Fatigue that doesn’t improve with sleep
- Dizziness or lightheadedness when you stand up
- Salt cravings
- Darkening of the skin, especially in skin creases, gums, or scars
- Unexplained weight loss
- Low sodium or high potassium on blood tests
- Other autoimmune conditions like type 1 diabetes, vitiligo, or pernicious anaemia
These are the flags that point toward adrenal insufficiency running alongside the thyroid disease. Missing them before treatment carries real risk.
Can I Take Ashwagandha If I Have Hashimoto’s?
Ashwagandha is a commonly used adaptogen that people take to lower cortisol and manage stress. It does have evidence behind it for reducing cortisol in chronically stressed adults. The concern with Hashimoto’s specifically is that ashwagandha has immune-stimulating properties. Since Hashimoto’s is driven by immune overactivation, there’s a theoretical risk that stimulating the immune system further could worsen antibody levels or accelerate thyroid damage.
The clinical data on ashwagandha in Hashimoto’s is limited. There’s one small study suggesting it may improve thyroid hormone levels in subclinical hypothyroidism, but it didn’t specifically track autoantibodies over time in Hashimoto’s patients. What I found when looking at this practically is that some people with Hashimoto’s tolerate it fine, while others notice a flare in symptoms.
If you want to try ashwagandha, get your TPO antibodies tested before you start, run it for eight to twelve weeks, and test again. That gives you actual data on whether it’s helping or pushing your immune activity in the wrong direction. Don’t take it without that baseline, and tell your prescribing doctor before adding it to your routine.
What Most Articles Get Wrong About Cortisol and Hashimoto’s
Most content on this topic either overclaims a direct link between Hashimoto’s and high cortisol, or dismisses the cortisol question entirely. Here’s what actually gets missed:
First: The cortisol-Hashimoto’s relationship isn’t one-directional. Chronic stress may contribute to triggering or worsening thyroid autoimmunity through HPA-immune crosstalk, but Hashimoto’s doesn’t predictably raise cortisol in return. Assuming you have high cortisol because you have Hashimoto’s leads people toward supplements and protocols that address the wrong problem.
Second: Slow cortisol clearance in hypothyroidism can make cortisol levels appear elevated on tests when production is actually normal. This gets misread as “adrenal fatigue” or HPA overactivation, when what’s actually needed is better thyroid treatment.
Third: The most dangerous cortisol scenario in Hashimoto’s isn’t high cortisol, it’s undiagnosed adrenal insufficiency being exposed by thyroid treatment. This is underscreened, underdiagnosed, and the consequences of missing it are severe.
FAQ
Does Hashimoto’s directly raise cortisol?
Not reliably. Studies show cortisol going up in some Hashimoto’s patients and down in others. It’s not a consistent or predictable effect of the disease itself.
Can Hashimoto’s cause adrenal problems?
Yes, indirectly. People with one autoimmune condition are at higher risk of developing others. Autoimmune adrenal failure (Addison’s disease) can coexist with Hashimoto’s, and starting thyroid treatment without checking adrenal function first can be dangerous.
Should I get my cortisol tested if I have Hashimoto’s?
Get it tested if you have symptoms that suggest adrenal insufficiency: persistent fatigue, dizziness on standing, salt cravings, skin darkening, or abnormal electrolytes. Also test before starting levothyroxine if you have any of those signs or other autoimmune conditions.
Can stress make Hashimoto’s worse?
Yes. Chronic stress activates the HPA axis and shifts immune activity in ways that can influence thyroid autoimmunity. Managing stress isn’t just wellness advice, it has a real biological basis in this condition.
Is ashwagandha safe with Hashimoto’s?
The evidence is limited. It may lower cortisol effectively, but its immune-stimulating properties are a concern with autoimmune thyroid disease. Test your antibodies before and after to monitor the effect.
What to Do Now
If you have Hashimoto’s and are about to start thyroid hormone replacement, ask your doctor for a morning cortisol and ACTH stimulation test first, especially if you have unexplained fatigue, dizziness, salt cravings, skin changes, or other autoimmune conditions. That one test could prevent a serious crisis.
If your thyroid is well-managed and you feel stable, high cortisol from Hashimoto’s alone isn’t your primary concern. Focus on consistent sleep, structured movement, and real stress reduction. Those tools directly influence the HPA-immune axis that connects your stress response to your thyroid health.
Sources
- Agha-Hosseini F, Shirzad N, Moosavi MS (2016) “The association of elevated plasma cortisol and Hashimoto’s Thyroiditis, a neglected part of immune response” Acta clinica Belgica. PMID: 27075805
- Legakis I, Petroyianni V, Saramantis A, Tolis G (2001) “Elevated prolactin to cortisol ratio and polyclonal autoimmune activation in Hashimoto’s thyroiditis” Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme. PMID: 11607877
- Tsinopoulou VR, Kolanis S, Katsarou D, Kotanidou EP, Galli-Tsinopoulou A (2025) “Thyroxine Reveals Addison’s Disease: A Case Report” Cureus. PMID: 40688962
- Zacharia GS, Jacob A, Bose BM (2024) “Schmidt’s Syndrome: An Uncommon Cause of Spontaneous Hypoglycemia” Avicenna journal of medicine. PMID: 38957156
- Schafroth C, Oestmann A (2022) “[Just Anorexia?]” Praxis. PMID: 36102024
- Stahn B, Scheit L (2019) “[The Schmidt’s Syndrome]” Deutsche medizinische Wochenschrift (1946). PMID: 31791082
- Tsatsoulis A (2006) “The role of stress in the clinical expression of thyroid autoimmunity” Annals of the New York Academy of Sciences. PMID: 17192582
- Webster EL, Torpy DJ, Elenkov IJ, Chrousos GP (1998) “Corticotropin-releasing hormone and inflammation” Annals of the New York Academy of Sciences. PMID: 9629233
