From the FDA Drug Label
• Instruct patients to take levothyroxine sodium tablets as a single dose, preferably on an empty stomach, one-half to one hour before breakfast with a full glass of water to avoid choking or gagging.
Levothyroxine (T4) should be taken before meals, preferably on an empty stomach, one-half to one hour before breakfast. 1
From the Research
Levothyroxine should be taken at bedtime on an empty stomach, as this timing has been shown to significantly improve thyroid hormone levels compared to morning intake 2. When considering the optimal timing for levothyroxine administration, it's essential to prioritize the most recent and highest quality study. The study published in 2010 in the Archives of Internal Medicine 2 demonstrated that taking levothyroxine at bedtime resulted in decreased thyrotropin levels and increased free thyroxine and total triiodothyronine levels, indicating improved thyroid hormone levels. Some key points to consider when taking levothyroxine include:
- Taking the medication on an empty stomach to ensure optimal absorption
- Consistency in timing, whether taken in the morning or at bedtime
- Avoiding interference from other substances like calcium supplements, iron supplements, or antacids
- Maintaining stable thyroid function through consistent blood levels While other studies, such as those published in 2015 3, 4 and 2013 5, provide valuable insights into the effects of levothyroxine administration timing, the 2010 study 2 remains the most relevant and highest quality evidence for guiding clinical practice. Additionally, a more recent study from 2022 6 focused on the bioavailability of a novel levothyroxine solution, but its findings do not directly impact the recommendation for the timing of standard levothyroxine intake. Therefore, based on the strongest evidence, taking levothyroxine at bedtime is recommended for optimal thyroid hormone levels and overall management of hypothyroidism.