Levothyroxine replaces the hormone an underactive thyroid is not making. It is a replacement, not a stimulant, and how you take it matters as much as the dose.
- Generic name
- Levothyroxine sodium
- Active ingredient
- Levothyroxine sodium
- Common brands in India
- Thyronorm, Eltroxin, Thyrox, Lethyrox
- Available as
- Tablet
- Common strengths
- 12.5 mcg, 25 mcg, 50 mcg, 75 mcg, 88 mcg, 100 mcg, 112 mcg, 125 mcg
- How it is sold
- Prescription only — needs a doctor's prescription
No dosage information on this page
The correct dose depends on your age, weight, kidney and liver function, other medicines and medical history. Follow the dose your doctor prescribed, or the instructions on the pack. Never copy a dose from a website or from someone else's prescription.
What Levothyroxine is used for
- Hypothyroidism — an underactive thyroid
- After surgical removal of the thyroid, or after radioactive iodine treatment
- Congenital hypothyroidism in babies, detected by newborn screening
- Thyroid hormone replacement during pregnancy, where requirements usually increase
How it works
Levothyroxine is a manufactured version of thyroxine, the hormone your thyroid normally produces. It simply replaces what is missing, restoring the body's normal pace. It does not force the thyroid to work harder.
How to take Levothyroxine
- Take it on an empty stomach with water, usually first thing in the morning, and wait 30 to 60 minutes before eating or drinking anything else. Tea and coffee reduce absorption noticeably.
- Keep a gap of at least four hours from calcium tablets, iron tablets, antacids and multivitamins. These bind the medicine in the gut so less of it reaches your blood.
- Take it every single day at the same time. Missed days shift your blood levels more than most people expect.
- Try to stay on the same brand. Small differences between manufacturers can move your levels enough to matter.
Precautions
- Your dose is set by repeat TSH blood tests, usually six to eight weeks after any change.
- Tell your doctor immediately if you become pregnant — the dose almost always needs increasing early in pregnancy, and the baby's development depends on it.
- Store tablets away from heat and humidity.
Common side effects
Not everyone gets side effects. Tell your doctor if any of these are troublesome or do not settle.
- At the correct dose, there are usually no side effects at all — you are simply replacing a missing hormone
- Side effects generally mean the dose is too high rather than that the medicine disagrees with you
- Too much causes palpitations, tremor, feeling hot, anxiety, difficulty sleeping, loose motions and unintended weight loss
Important warnings
- Never increase the dose yourself hoping to lose weight or gain energy. Excess thyroid hormone causes irregular heart rhythms and thins the bones over time.
- Do not stop taking it because you feel well. You feel well because the medicine is working.
- Tell your doctor about palpitations, a racing heartbeat, chest pain or severe anxiety after a dose change.
- Older people and anyone with heart disease usually start on a low dose that is increased slowly.
Frequently Asked Questions
Why must levothyroxine be taken on an empty stomach?
Food, tea, coffee, calcium and iron all reduce how much of the tablet your body absorbs. Taking it with water on an empty stomach and waiting 30 to 60 minutes keeps the amount reaching your blood consistent from day to day, which is what makes your dose reliable.
What happens if I miss a dose?
Take it as soon as you remember on the same day. If you only remember the next day, ask your doctor — some advise taking two tablets the following morning, but you should follow their instruction rather than deciding yourself. Missing an occasional dose is not a crisis; the hormone stays in the body for days.
Can I change brands of levothyroxine?
It is better not to switch without telling your doctor. Different brands can deliver slightly different amounts, and for this particular medicine that difference can be enough to change your TSH. If a brand switch is unavoidable, your doctor may want to recheck your levels.
Will levothyroxine help me lose weight?
Not if your thyroid levels are already normal. It corrects the modest weight gain and fluid retention caused by an underactive thyroid, but taking extra is not a weight-loss method — it is dangerous for the heart and bones.
What are the side effects of levothyroxine?
At the correct dose there are usually none at all, because you are simply replacing a hormone your body is short of. Side effects generally mean the dose is too high rather than that the medicine disagrees with you — palpitations, tremor, feeling hot, anxiety, poor sleep, loose motions and unintended weight loss are the signs to report.
What this costs, and what is free
Commonly available free at government hospitals and health and wellness centres when prescribed there.
Generic versions are sold at Jan Aushadhi Kendras at substantially lower prices than branded packs of the same medicine.
The same molecule is sold under many brand names at very different prices. Ask your doctor to write the generic name, and compare at a Jan Aushadhi Kendra — the saving on a medicine taken daily is often substantial over a year. You can look up any medicine's official ceiling price on NPPA's Pharma Sahi Daam app.
Source: Pradhan Mantri Bhartiya Janaushadhi Pariyojana (PMBJP), National Pharmaceutical Pricing Authority (NPPA)
Prices and scheme rules change. Confirm current details with the hospital or Kendra before you rely on them.
Looking for Levothyroxine locally?Aswini Medicals is a pharmacy that stocks everyday medicines and can advise on availability.
Visit Aswini Medicals