STUDY OFFERS GUIDANCE ON TAKING THYROID HORMONE WITH FOOD
February 2026
Food reduces the absorption of levothyroxine (LT4) tablets, so guidelines recommend taking them on an empty stomach (typically 30 to 60 minutes before breakfast) to optimize absorption. Many patients find this routine onerous; delaying breakfast can be burdensome, and surveys show that a substantial proportion do not consistently adhere to fasting timing, skip breakfast to comply, or forget doses. A recent study evaluated whether increasing the LT4 dose by 15% and taking it with breakfast could maintain TSH stability and improve convenience.
The trial was an open-label, randomized clinical trial at a single center in the Netherlands. Adults with hypothyroidism were eligible if they were on a stable LT4 dose (≥1.0 mcg/kg), ate breakfast on ≥5 days per week, and had two consecutive TSH values within the reference range (0.27–4.20 mIU/L) before randomization. Eighty-eight patients (median age 62 years; ~81% female) were randomized 1:1 to fasting LT4 (30–60 minutes before breakfast) or to taking LT4 with breakfast with a 15% dose increase. TSH, free T4, and total T3 were measured every 6 weeks, with dose adjustments as needed. The primary outcome was the proportion of patients reaching TSH stability, defined as two consecutive values in range and a change from baseline TSH of ≤1 mIU/L. Patients were followed until they reached the primary endpoint or up to 24 weeks. At the end of the trial, 74.4% in the fasting group and 73.3% (95% CI 60.0–87.0%) in the breakfast group (P>0.05) achieved TSH stability. Median time to stability was 12 weeks in both groups. Self-reported well-being improved in 33.3% of the breakfast group compared to 16.3% in the fasting group (P=0.07). In the breakfast group, 88.9% of patients chose to continue taking LT4 with breakfast after the study. In a crossover analysis, patients who switched from fasting to breakfast intake with the 15% dose increase achieved similar TSH stability (66.7% vs 72.2% during fasting; P>0.05).
For patients who wish to switch from taking their LT4 fasting to taking it with breakfast, this trial provides guidance on the initial dose adjustment. A 15% increase is a valid starting point, with TSH monitoring 6 weeks after the change. Of note, Tirosint® is a form of levothyroxine that comes in a soft gelatin capsule. The study authors stated that its absorption is not affected by food; however, the Tirosint® prescribing information recommends taking it on an empty stomach.
