Underactive Thyroid
An underactive thyroid slows nearly every system in the body. The good news: it is highly treatable once it's properly diagnosed and the right medication is matched to you.
Overview
Hypothyroidism means your thyroid gland isn't producing enough thyroid hormone to meet your body's needs. Thyroid hormone sets your metabolic pace, so when levels fall, everything slows — energy, digestion, mood, temperature regulation, and weight control. Because the symptoms build gradually and overlap with ordinary stress and aging, hypothyroidism is frequently missed or dismissed for years.
The most common cause in the United States is Hashimoto's thyroiditis, an autoimmune condition in which the immune system gradually reduces the thyroid's ability to produce hormone. Other causes include thyroid surgery, radioactive iodine treatment, certain medications, and iodine imbalance.
Symptoms
Hypothyroid symptoms are wide-ranging because thyroid hormone touches every tissue. The most common include persistent fatigue, unexplained weight gain, cold intolerance, hair thinning, dry skin, constipation, low mood, and difficulty concentrating ("brain fog"). Many patients describe simply not feeling like themselves.
We cover the full picture on our hypothyroidism symptoms page, including the subtle, easy-to-miss signs.
Diagnosis
Most conventional workups stop at TSH. But TSH is a pituitary signal, not a direct measure of the active hormone reaching your cells. Two people with identical TSH values can feel completely different. That's why we run a comprehensive thyroid panel — TSH, Free T4, Free T3, Reverse T3, and thyroid antibodies — and interpret it alongside your symptoms rather than just the lab's reference range.
Treatment
Standard treatment is levothyroxine (synthetic T4), and for many patients it works well. But a meaningful subset continues to feel unwell on T4 alone — often because they don't convert T4 to the active T3 hormone efficiently. For those patients we consider T3/T4 combination therapy or natural desiccated thyroid. The goal is always the same: relief of symptoms with labs in a healthy range, not just a number that's technically 'normal.'
Common Questions
Clinical references: American Thyroid Association · Endocrine Society
Keep Exploring
If you have hypothyroid symptoms but keep getting dismissed, a comprehensive evaluation can find what a single TSH misses. Book a consultation and let's look deeper.
Available across California via telehealth · in-person in Chatsworth & Santa Barbara.