A complete panel, not just TSH
Many patients arrive after years of TSH-only testing. Dr. Shah orders TSH with free T4, free T3, and thyroid antibodies so that poor conversion of T4 to T3 or an underlying autoimmune cause is not missed.
Condition
Hypothyroidism Treatment in Diamond Bar, CA
Hypothyroidism means the thyroid gland does not produce enough thyroid hormone to meet the body's needs, which slows metabolism and affects energy, weight, mood, digestion, and temperature regulation. It is diagnosed with blood tests — most commonly an elevated TSH with a low or low-normal free T4 — and it is usually treated with daily thyroid hormone replacement. In most adults the underlying cause is Hashimoto's thyroiditis, an autoimmune condition.
4.8 stars · 106 patient reviews
Dr. Hitendra H. Shah, MD · 40+ years · 5,000+ patients treated
Symptoms
Symptoms we see with Hypothyroidism
Patients across Diamond Bar, Chino Hills, Walnut, Rowland Heights, Brea, and Pomona most often describe the following. You do not need all of them for Hypothyroidism to be worth evaluating.
- Persistent fatigue and low stamina
- Unexplained weight gain or trouble losing weight
- Feeling cold when others are comfortable
- Brain fog, slowed thinking, and memory lapses
- Dry skin, brittle nails, and hair thinning
- Constipation
- Depressed mood or flat affect
- Muscle aches, cramps, and weakness
- Puffiness around the eyes and face
- Heavy or irregular menstrual periods and fertility difficulty
Our approach
How Dr. Shah approaches Hypothyroidism
Functional, whole-person care: comprehensive testing, a search for the underlying cause, careful medication optimization, and lifestyle and hormone support — delivered by one named specialist rather than a rotating hospital group.
Finding the root cause
Hypothyroidism has causes — autoimmune thyroiditis, prior thyroid surgery or radioactive iodine, medications, iodine or nutrient issues, and pituitary problems among them. Identifying which one applies changes both the monitoring plan and what to expect long term.
Medication optimization
Being on levothyroxine is not the same as being well treated. Timing, absorption, interacting supplements such as iron and calcium, and formulation are reviewed, and doses are adjusted gradually with follow-up labs and a conversation about symptoms.
Whole-person and hormone support
Iron, vitamin D, B12, blood sugar, cholesterol, cortisol patterns, and sex hormones are evaluated alongside the thyroid because they shape how you feel even when thyroid numbers improve.
Continuity with one specialist
With 40+ years of practice and more than 5,000 patients treated, Dr. Shah manages your case personally instead of handing you to whoever is on rotation at a hospital group.
This page is general health education about hypothyroidism (underactive thyroid) and is not medical advice, a diagnosis, or a promise of any particular result. Treatment decisions, including any medication, are made individually during a visit.
Next step
When to see a thyroid specialist
Consider a focused evaluation in Diamond Bar if any of the following apply to you:
- You have classic symptoms and have never had a full thyroid panel.
- Your TSH is above range or borderline on repeat testing.
- You take thyroid medication and still feel tired, cold, or foggy.
- Your dose has been unchanged for years without symptom review.
- You are pregnant, planning pregnancy, or having fertility trouble.
- Your cholesterol rose or your weight changed without a clear reason.
Answers
Hypothyroidism: questions patients ask
- Do you feel better on Armour Thyroid than Synthroid?
- Many patients do. Synthroid is T4-only and relies on the body converting T4 into T3, while Armour Thyroid (natural desiccated thyroid) contains both T4 and T3. Not everyone converts efficiently, which is why some patients feel better on NDT or a combination T4 + T3 approach.
- What tests diagnose hypothyroidism?
- Hypothyroidism is diagnosed with a blood test showing an elevated TSH, usually confirmed with a low or low-normal free T4. Free T3 and TPO antibodies are added to identify poor T4-to-T3 conversion and autoimmune causes such as Hashimoto's thyroiditis. Testing is generally repeated to confirm before starting long-term treatment.
- Why do I still feel tired if my TSH is normal?
- A normal TSH does not always mean optimal thyroid function. Free T4 and free T3 levels, iron and ferritin, vitamin D, B12, sleep quality, blood sugar, and sex hormones all affect energy. A full evaluation looks at those together instead of stopping at a single value.
- Is hypothyroidism permanent?
- Most adult hypothyroidism from Hashimoto's or thyroid surgery is permanent and requires lifelong hormone replacement. Some cases — after certain viral thyroid inflammation, some medications, or pregnancy-related thyroiditis — are temporary and thyroid function recovers. Which one applies is determined by the cause and by repeat testing.
- Can hypothyroidism cause weight gain?
- Yes. Low thyroid hormone slows metabolism and commonly causes several pounds of weight gain, much of it fluid retention. Treating the thyroid usually helps but rarely resolves significant weight gain on its own, so metabolic factors such as insulin resistance are evaluated in the same visit.
- How long does thyroid medication take to work?
- Most patients notice some improvement within two to four weeks, with the fuller effect over about six to eight weeks. Labs are typically rechecked about six weeks after any dose change because levels take that long to stabilize.
- Should I see an endocrinologist or a thyroid specialist?
- Consider a specialist if your symptoms persist despite treatment, your labs are difficult to interpret, you have nodules or antibodies, or you are pregnant. At Wellness Medical Clinic & Thyroid Treatment Center in Diamond Bar, Dr. Shah provides that focused thyroid evaluation directly.
Keep exploring
Related conditions and services
Related conditions
Services that support this care
Written and reviewed by Dr. Hitendra H. Shah, MD. Last updated: August 11, 2026.
Diamond Bar, California
Get a clear answer about Hypothyroidism
Request an appointment with Dr. Hitendra H. Shah, MD at our Diamond Bar clinic and start with a complete thyroid and hormone evaluation.