Low thyroid function makes you tired, slows your metabolism, and can mess with mood and weight. The good news: most people respond well to treatment when it's tailored to their needs. This page gives clear, practical steps you can discuss with your doctor so you start feeling better without guessing.
The standard treatment is levothyroxine, a synthetic T4 hormone. Doctors choose a starting dose based on your age, weight, heart health, and how low your thyroid is. Common starting doses range from 25–50 mcg for older adults or people with heart disease, up to 75–125 mcg for many others. A common rule is about 1.6 mcg per kilogram of body weight for a full replacement dose, but your doctor will adjust that.
After starting or changing the dose, your doctor will check TSH and free T4 about every 6–8 weeks. Lab results guide dose changes. Pregnant people and those trying to conceive need tighter control and often require higher doses. If levothyroxine alone doesn't fix symptoms, some doctors consider adding liothyronine (T3) or a trial of combination therapy, but that’s a personalized decision with pros and cons.
How you take levothyroxine matters. Take it on an empty stomach with a full glass of water, ideally 30–60 minutes before breakfast. Avoid calcium, iron, antacids, and high-fiber meals within four hours—they can cut absorption. Try to stick with one brand or generic type, since small differences can change levels.
Diet and habits also matter. Iodine is needed for thyroid hormone, but too much salt or supplements with iodine can cause trouble. If you eat a lot of soy, high-fiber foods, or take supplements, mention it to your clinician because these affect medication and labs. Selenium supplements may help some people with autoimmune thyroiditis, but ask before starting any new pill.
Lifestyle supports treatment. Regular walking, strength training, and enough sleep ease fatigue and help weight control. Track symptoms—energy, temperature tolerance, hair and skin changes, bowel patterns—and share that list at appointments. Small wins add up: better sleep, regular meals, and moving a few times a week improve how you feel even before labs normalize.
Travel, new prescriptions, and seasonal illnesses can change your dose needs. If you start a new drug — especially antidepressants, blood thinners, or heart meds — tell your thyroid clinician. When flying across time zones, keep dosing consistent (local morning works) and bring extra pills with a copy of your prescription. Small planning prevents big problems.
When to call your doctor? If you get chest pain, palpitations, sudden weight loss, or feel dizzy after a dose change, seek care. Also schedule a check if symptoms persist despite normal lab tests—sometimes doses need fine-tuning or another issue is at play.
Want to change therapy or try natural products? Talk it over with a clinician. Proper testing, careful dosing, and simple daily habits are the fastest path to feeling like yourself again. Stay proactive.
