Hypothyroidism: Causes, Symptoms, and Treatment Options

When your hypothyroidism, a condition where the thyroid gland doesn’t make enough thyroid hormone to keep your metabolism running properly. Also known as underactive thyroid, it slows down just about everything in your body—from how fast you burn calories to how well you think and feel. It’s not rare. Millions of people live with it, often without knowing why they’re always tired, gaining weight, or feeling cold when others aren’t.

Most cases come from autoimmune thyroid disease, where the immune system mistakenly attacks the thyroid gland, damaging its ability to produce hormones. This is called Hashimoto’s thyroiditis, and it’s the #1 cause in the U.S. Other triggers include radiation treatment, thyroid surgery, certain medications, or even iodine deficiency—though that’s rare in places with iodized salt. Your thyroid hormone, mainly T4 and T3, controls energy, body temperature, heart rate, and brain function. When levels drop, you don’t just feel sluggish—you might get dry skin, hair loss, constipation, depression, or heavy periods.

Testing for hypothyroidism is simple: a blood test checks TSH (thyroid-stimulating hormone) and free T4. High TSH with low T4? That’s a clear signal. But some people have normal lab numbers and still feel awful. That’s why symptoms matter just as much as numbers. The standard treatment is levothyroxine, a synthetic version of T4 that replaces what your thyroid isn’t making. It’s cheap, effective, and taken once a day on an empty stomach. Most people start feeling better in weeks, but finding the right dose can take time. Some switch to combination therapies or natural desiccated thyroid, but those aren’t backed by strong evidence for everyone.

What you won’t find in most guides is how diet, stress, and sleep play into managing this condition. You can’t cure hypothyroidism with kale or coconut oil, but good sleep and less stress help your body respond better to medication. Avoiding soy and calcium supplements right before your pill also matters—these can block absorption. And if you’re on levothyroxine, you need to get your levels checked at least once a year, more if you’re pregnant or changing doses.

Below you’ll find real comparisons and guides from people who’ve been there. We’ve pulled together posts that break down how different medications stack up, what side effects to watch for, and how other conditions like liver health or gut issues can interfere with treatment. Whether you’re just diagnosed or have been managing this for years, you’ll find practical advice—not theory, not fluff, just what works.