Patient Guide
Underactive Thyroid
Hypothyroidism — the signs, the tests, and how it's treated
Butterflygland in your neck that sets your body's pace
TSHthe main blood test — it rises when the thyroid is slow
Very treatablea simple daily tablet usually restores your levels
When your thyroid runs slow. Your thyroid is a small, butterfly-shaped gland in your neck that sets your body's pace. When it's underactive everything slows down — and the good news is it's common and very treatable.
Signs of an underactive thyroid
Tired & sluggish
Low energy and slowed down — sleeping more but still feeling tired.
Weight gain
Putting on weight or struggling to lose it, as your metabolism slows.
Feeling the cold
Feeling cold when others are comfortable, with cool hands and feet.
Dry skin & hair
Dry or rough skin, and dry, thinning hair or brittle nails.
Low mood & brain fog
Feeling flat or down, with slower thinking, memory or concentration.
Constipation & cramps
A sluggish gut, muscle aches or cramps, and sometimes heavier periods.
Borderline result? ("subclinical") Sometimes the TSH is only mildly up while your thyroid hormone (T4) is still normal. This often causes few or no symptoms and can settle on its own, so we may simply recheck in a few months. We're quicker to treat if the TSH is high, you have symptoms or thyroid antibodies, or you're pregnant or planning to be.
The treatment: thyroxine
Replaces the hormone
Levothyroxine (thyroxine) is the same hormone your thyroid makes — it simply tops it back up.
Taken as one tablet daily
Usually long-term
Often lifelong, especially with Hashimoto's — though some mild or temporary cases don't need it forever.
Some cases are only short-term
Fine-tuned by tests
We adjust the dose using your TSH blood test; it takes about 6 weeks to settle after a change.
Aiming to ease your symptoms
Getting the most from your tablet
Take it well
- Same time each day on an empty stomach — either morning (30–60 min before food or coffee) or bedtime, 3+ hours after eating
- Swallow with water; coffee, milk and food lower how much you absorb
- Keep iron, calcium, antacids and multivitamins about 4 hours apart from it
- Don't stop suddenly; if you miss a dose, take it when you remember
Good to know
- Tell us if you're pregnant or planning to be — you'll need more, and prompt testing
- Once you're stable, occasional blood tests keep the dose right
- Too much can cause over-active symptoms — palpitations, feeling wired, weight loss
- If you still feel off once your TSH is normal, let's look for other causes too
Will I feel better?
Most people feel back to themselves once the dose is right, though it can take a few weeks. Tiredness and weight aren't always only the thyroid — so we treat you and your symptoms, not just the number.
An underactive thyroid is very manageable
The right daily dose → your energy, weight and mood usually settle. A simple tablet and the odd blood test keep you on track.
— Dr Regu
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