Why Hashimoto’s Makes You So Tired (And How to Get Your Energy Back)

Why Hashimoto’s fatigue is so common

If you feel exhausted no matter how much sleep you get, struggle to stay focused, or experience energy crashes throughout the day, you’re not alone. Hashimoto’s thyroiditis, an autoimmune condition that attacks the thyroid, is one of the most overlooked causes of chronic fatigue. Many people with Hashimoto’s are told their thyroid levels are “normal,” yet they still feel drained, foggy, and unable to function at their best.

Hashimoto’s fatigue isn’t just about low thyroid hormones. It’s a complex issue involving metabolism, inflammation, mitochondrial function, and adrenal health. According to research, many individuals with Hashimoto’s experience fatigue that is not resolved with thyroid medication alone. Understanding the root causes of this exhaustion is the first step toward regaining your energy and improving your overall well-being.

How Hashimoto’s impacts energy levels

One of the main reasons Hashimoto’s leads to extreme fatigue is its effect on metabolism. Since the thyroid acts as the body’s metabolic regulator, when it underperforms, everything slows down—including calorie burning and energy production. Research shows that low thyroid function reduces basal metabolic rate, making people feel sluggish and tired even after a full night’s rest.

Mitochondria, the energy powerhouses of your cells, also take a hit when thyroid function is compromised. The body relies on thyroid hormones to stimulate mitochondrial activity and produce ATP, the fuel that powers every cell. Without enough ATP, the body struggles to generate energy, resulting in persistent fatigue and muscle weakness. 

Another major culprit is chronic inflammation. Since Hashimoto’s is an autoimmune disorder, the immune system is constantly active, producing inflammatory cytokines that can lead to widespread fatigue and brain fog. This inflammatory response affects brain function, making it harder to concentrate and process information. Studies suggest that increased inflammation can also disrupt sleep cycles, further contributing to exhaustion.

Stress and adrenal function also play a crucial role. Many people with Hashimoto’s experience cortisol imbalances, which can lead to energy crashes, sleep disturbances, and an inability to handle stress effectively. Chronic stress depletes thyroid function and creates a vicious cycle of fatigue. Research has shown that individuals with Hashimoto’s often have dysregulated cortisol patterns, leading to symptoms of both adrenal fatigue and thyroid dysfunction.

Why thyroid medication alone may not fix your fatigue

For many people with Hashimoto’s, thyroid medication doesn’t completely restore their energy levels. One reason is that the standard treatment, levothyroxine (T4), is an inactive form of thyroid hormone. The body must convert T4 into T3, the active thyroid hormone responsible for energy metabolism. However, not everyone converts T4 efficiently, leaving them with low active thyroid levels even if their TSH appears normal.

Another issue is high levels of reverse T3 (RT3), which blocks the body’s ability to use thyroid hormones effectively. When the body produces too much RT3—often in response to stress, inflammation, or low-calorie diets—it can lead to persistent fatigue and metabolic slowdowns. Research suggests that individuals with elevated RT3 often experience symptoms of hypothyroidism despite having “normal” thyroid labs.

Nutrient deficiencies also play a role. Thyroid function relies on specific nutrients, including selenium, iron, magnesium, B12, and vitamin D, to support hormone production and conversion. Without these essential vitamins and minerals, thyroid medication may not work as effectively, and fatigue can persist. Studies in Nutrients confirm that deficiencies in these key nutrients are common in individuals with Hashimoto’s and contribute to ongoing fatigue.

Practical steps to regain energy with Hashimoto’s

Optimise thyroid hormone levels

Getting your thyroid hormone levels properly balanced is crucial. Work with a knowledgeable doctor to check Free T3, Free T4, Reverse T3, and TSH to determine if your current treatment plan is truly supporting your energy levels. Some people feel significantly better when they switch from T4-only medications like levothyroxine to combination therapy that includes T3-based medication (such as liothyronine or natural desiccated thyroid).

Balance blood sugar for steady energy

Many people with Hashimoto’s struggle with insulin resistance, which leads to energy crashes and cravings for sugar and carbs. Stabilising blood sugar by eating protein, healthy fats, and fibre at every meal can help prevent energy dips.

Reduce inflammation & support gut health

Since inflammation plays a huge role in Hashimoto’s fatigue, focusing on anti-inflammatory foods can help restore energy. Reducing processed foods and refined sugar can lower inflammation and improve overall thyroid function.

Gut health is also closely linked to Hashimoto’s. Supporting your gut microbiome with fermented foods, bone broth, and prebiotic-rich foods can improve digestion and enhance nutrient absorption. Some people find that eliminating gluten, dairy, soy, and nightshades reduces their symptoms, as these foods can trigger immune reactions in people with Hashimoto’s. Studies suggest that a gluten-free diet may improve symptoms in individuals with autoimmune thyroid disease.

Manage stress & improve sleep

Chronic stress depletes thyroid function and can make fatigue even worse. Mindfulness practices, yoga, deep breathing, and regular walks have been shown to lower cortisol levels and support adrenal health. Research in Psychoneuroendocrinology suggests that stress-reducing activities can significantly improve fatigue and well-being in people with thyroid conditions.

Getting 7-9 hours of quality sleep is another crucial factor. Poor sleep increases inflammation and disrupts thyroid hormone production. Avoiding blue light before bed, maintaining a consistent sleep schedule, and creating a relaxing nighttime routine can all improve sleep quality and restore energy levels.

Key nutrients to boost energy with Hashimoto’s

Several nutrients are essential for energy production and thyroid function:

• Iron & ferritin – Needed for proper thyroid hormone function and oxygen transport.
• Magnesium – Supports ATP production, the body’s main energy source.
• Vitamin B12 – Essential for red blood cell production and energy metabolism.
• Selenium & zinc – Help convert T4 into active T3.
• Vitamin D – Supports immune function and helps reduce fatigue.

Ensuring adequate intake of these nutrients through diet or supplementation can significantly improve energy levels.