From Hormones to Liver Health: Understanding Hypothyroidism’s Role in Fatty Liver Disease

When we think about thyroid health and liver health, most of us imagine two separate systems. The thyroid gland makes hormones that regulate metabolism, while the liver filters toxins and processes food. But research shows these two organs are deeply connected — especially when it comes to non-alcoholic fatty liver disease (NAFLD), a condition where fat builds up in the liver independent of alcohol use.

NAFLD is one of the most common liver conditions worldwide, and it often appears in people with hypothyroidism (an underactive thyroid). Understanding this link can help you take better care of your metabolism, hormone balance, and overall wellness.

How the Thyroid Affects the Liver

The thyroid gland regulates metabolism, energy balance, and fat processing. When thyroid hormones are low, metabolism slows. This makes it harder for the body to break down fats, often leading to:

• Increased cholesterol
• Insulin resistance
• Fat accumulation in the liver

Hypothyroidism and NAFLD Risk

People with hypothyroidism (an underactive thyroid) are at a higher risk of NAFLD. Studies suggest that low thyroid hormone levels can impair the liver’s ability to burn fat, triggering inflammation and scarring (fibrosis) if left unchecked. Even mild, “subclinical” hypothyroidism has been linked to a greater chance of fatty liver. If your thyroid hormone replacement medications are not giving you optimal labs, you are at risk for NAFLD.

Shared Risk Factors

Both thyroid disease and NAFLD often overlap with:

• Obesity
• Type 2 diabetes
• Metabolic syndrome
• Hormonal imbalances

This makes it difficult to separate the two—but also means improving thyroid function may ease liver strain.

Supporting Both Organs

If you have thyroid disease, protecting your liver is key. Steps include:

• Regular thyroid and liver function tests
• Eating a nutrient-rich, balanced diet
• Maintaining a healthy weight
• Managing blood sugar and cholesterol
• Avoiding unnecessary medications and alcohol
  
  

The Takeaway

Thyroid disease and non-alcoholic fatty liver disease are more than just coexisting conditions—they are metabolically intertwined. Addressing one often benefits the other. If you have thyroid issues, it’s worth talking to your doctor about your liver health, insulin and Hba1c levels, and making sure your thyroid hormones are optimal.

References

1. He W, An X, Li L, Shao X, Li Q, Yao Q. Relationship between hypothyroidism and non-alcoholic fatty liver disease: a systematic review and meta-analysis. Front Endocrinol (Lausanne). 2017;8:335. doi:10.3389/fendo.2017.00335
2. Kim D, Kim W, Joo SK, Bae JM, Kim JH, Ahmed A. Subclinical hypothyroidism and low-normal thyroid function are associated with nonalcoholic steatohepatitis and fibrosis. Clin Gastroenterol Hepatol. 2018;16(1):123-131.e1. doi:10.1016/j.cgh.2017.08.002
3. Xu C, Xu L, Yu C, Miao M, Li Y. Association between thyroid function and nonalcoholic fatty liver disease in euthyroid and subclinical hypothyroid subjects. Endocrine. 2011;39(2):60-65. doi:10.1007/s12020-010-9402-9
4. Chung GE, Kim D, Kim W, et al. Non-alcoholic fatty liver disease across the spectrum of hypothyroidism. J Hepatol. 2012;57(1):150-156. doi:10.1016/j.jhep.2012.02.027
5. Bano A, Chaker L, Plompen EPC, et al. Thyroid function and the risk of nonalcoholic fatty liver disease: the Rotterdam Study. J Clin Endocrinol Metab. 2016;101(8):3204-3211. doi:10.1210/jc.2016-1300
6. Harrison SA, Bashir MR, Guy CD, et al. Resmetirom (MGL-3196) for the treatment of non-alcoholic steatohepatitis: a multicentre, randomized, double-blind, placebo-controlled, phase 2 trial. Lancet. 2019;394(10213):2012-2024. doi:10.1016/S0140-6736(19)32517-6