Understanding thyroid function
The thyroid gland produces T3 and T4 hormones that regulate metabolism, temperature, heart rate, weight, energy, mood, and virtually every organ system. The pituitary gland controls thyroid output via TSH (thyroid-stimulating hormone): when thyroid hormone is low, TSH rises; when it's high, TSH falls. This makes TSH the most sensitive screening test for thyroid dysfunction. Hypothyroidism (underactive thyroid, elevated TSH) is far more common than hyperthyroidism, affecting roughly 5% of adults in Peru — and many more with subclinical disease.
Hashimoto's thyroiditis is the most common cause of hypothyroidism in Peru and worldwide. It's an autoimmune condition where the immune system attacks thyroid tissue. Anti-TPO antibodies are elevated in over 90% of cases. It's more common in women, people with other autoimmune diseases (type 1 diabetes, celiac disease, rheumatoid arthritis), and those with a family history. Hashimoto's may fluctuate early in its course before eventually resulting in stable hypothyroidism requiring treatment.
Key facts
- ✓Hypothyroidism symptoms are non-specific and overlap with depression, anemia, and chronic fatigue — a TSH test is the only reliable way to diagnose it
- ✓Levothyroxine must be taken on an empty stomach, 30–60 minutes before breakfast, for consistent absorption
- ✓TSH takes 6–8 weeks to stabilize after any dose change — don't retest sooner
- ✓Many medications and supplements interfere with levothyroxine absorption — always inform your doctor
- ✓Once stable on treatment, annual TSH monitoring is sufficient for most patients
Thyroid follow-up from home
A physician can review your TSH results, adjust your levothyroxine dose, and renew your prescription — online from S/80.
Book consultation →Symptoms of hypothyroidism
Hypothyroidism symptoms develop gradually and are often attributed to aging or stress: persistent fatigue and lack of energy; unexplained weight gain despite no change in diet; feeling cold all the time; dry skin, brittle nails, and hair loss or coarse hair; constipation; bradycardia (slow heart rate); brain fog and difficulty concentrating; hoarse voice; muscle aches; irregular or heavy menstrual cycles; and depression. In severe untreated hypothyroidism, myxedema can develop — characterized by puffiness of the face, hands, and legs, slowed speech, and eventually reduced consciousness.
The insidious onset means many patients accept these symptoms as "normal" for months or years before seeking testing. If you have several of these symptoms — particularly fatigue, unexplained weight changes, and cold intolerance together — a TSH test is the simple, definitive next step. It requires no special preparation and is available at any private laboratory in Peru.
Get your thyroid checked online
Order TSH and get results reviewed by a physician — online from S/80, anywhere in Peru.
Book nowTreatment: levothyroxine
Levothyroxine (synthetic T4) is the standard treatment for hypothyroidism. Starting dose is typically 1.6 mcg/kg of ideal body weight per day, reduced in older patients and those with cardiovascular disease. It must be taken on an empty stomach (30–60 minutes before breakfast) every day — preferably at the same time. TSH is rechecked 6–8 weeks after starting or changing dose. Target TSH varies by patient: typically 0.5–2.5 mIU/L for most adults, with slightly higher targets acceptable in older patients.
Important interactions: calcium supplements, iron, antacids containing aluminum or magnesium, and certain cholesterol medications reduce levothyroxine absorption — take these at least 4 hours apart. Coffee taken within 30–60 minutes of the dose also reduces absorption. Once TSH is stable, annual monitoring is standard. Pregnancy, significant weight changes, and starting or stopping interacting medications warrant earlier retesting. The great advantage of hypothyroidism management: it's near-ideal for telemedicine — periodic lab review, dose adjustment, and prescription renewal, all without leaving home.
FAQ
Is hypothyroidism a lifelong condition?
In most cases of Hashimoto's thyroiditis, yes — thyroid function progressively declines and levothyroxine is needed indefinitely. However, some causes (thyroiditis after pregnancy or viral illness) may be transient. In subclinical hypothyroidism, a period of observation may be appropriate before committing to lifelong treatment — your doctor will advise based on antibody status, TSH level, and symptoms.
What medications interfere with levothyroxine?
Calcium carbonate, ferrous sulfate, antacids with aluminum or magnesium, sucralfate, cholestyramine, and proton pump inhibitors can all reduce absorption if taken close together. Always take levothyroxine alone, 30–60 minutes before breakfast, and inform your doctor of any supplements or new medications.
What is subclinical hypothyroidism?
Subclinical hypothyroidism means TSH is mildly elevated (4.5–10 mIU/L) but free T4 is normal and symptoms may be absent or mild. Treatment is generally recommended if TSH is above 10, if anti-TPO antibodies are positive, if the patient is pregnant or trying to conceive, or if there are clear symptoms. Otherwise, watchful waiting with annual TSH monitoring is appropriate.
How often should I check my TSH?
After a new diagnosis or dose change: 6–8 weeks. Once stable on treatment: annually. More frequently during pregnancy (every 4 weeks in the first trimester), after significant weight change, or when starting/stopping medications that affect absorption.
Conclusion
Hypothyroidism is one of the most common and most underdiagnosed hormonal conditions — and one of the most straightforward to treat. If you've been feeling persistently tired, cold, or unwell without explanation, a TSH test is the logical first step. Once on treatment, regular follow-up is simple and ideal for telemedicine.
At Delvir, you can consult a physician online from S/80, from anywhere in Peru.