Yoon asked
Levothyroxine for use in hypothyroidism 100 mcg. Does twice a day benefit more than taking it once a day?
Answer
Levothyroxine (brand name Levoxyl, Synthroid) is only recommended and indicated to be dosed once daily. This is based on the FDA approved indications for the drug and the medical guidelines for the treatment of hypothyroidism (1,2).
It is very important to take your levothyroxine dose the same way every day to ensure consistent absorption and effects. Below is the recommended dosing:
- Administer levothyroxine on an empty stomach with a full glass of water at least 30 to 60 minutes before breakfast. Rate and extent of absorption is best when administered in the fasting state (3).
Taking levothyroxine twice daily is not necessary for the drug to be effective and there is no evidence that more than once daily dosing confers any additional benefit. The long half-life (time it takes to metabolize 50% of the drug) has been referenced as the reason once daily dosing with levothyroxine is all that is necessary (4).
It should be noted that other thyroid replacement medication, such as Cytomel (liothyronine) and desiccated thyroid products (e.g. Armour Thyroid) are often recommended to be dosed twice daily due to their faster metabolism (5).
Having said all of the above, be sure to discuss with your doctor the best way to take levothyroxine for your specific medical situation.
