From the Research
Taking a thyroid hormone supplement at night is the most beneficial approach, as it improves absorption and aligns with the body's natural processing of thyroid hormones. This is supported by a study published in 2010, which found that levothyroxine intake at bedtime significantly decreased thyrotropin levels and increased free thyroxine and total triiodothyronine levels 1. The study, which was a randomized double-blind crossover trial, demonstrated that bedtime dosing can lead to more stable thyroid hormone levels and may even allow for lower doses in some patients.
Some key points to consider when taking thyroid hormone supplements include:
- Consistency is key, and the supplement should be taken at the same time each day
- Taking the supplement on an empty stomach, typically 3-4 hours after the last meal, can help improve absorption
- Individual responses may vary, and some people may still prefer morning dosing
- It's essential to consult with a healthcare provider before changing the medication schedule, as they can provide personalized advice based on the specific thyroid condition and other medications being taken
A more recent study published in 2021 found that levothyroxine ingestion in the morning and at bedtime are equally effective, but the co-administration of levothyroxine with food depends on the drug formulation 2. However, the 2010 study 1 provides stronger evidence for the benefits of nighttime dosing, and its findings are more relevant to the question of why a thyroid hormone supplement is best taken at night.
Other studies, such as those published in 2007 3 and 2013 4, also support the idea that nighttime dosing can improve thyroid hormone levels and reduce interference from food and other medications. However, the 2010 study 1 is the most relevant and provides the strongest evidence for the benefits of taking a thyroid hormone supplement at night.