Purpose <p>Randomized clinical trials (RCTs) have shown no benefit of levothyroxine for subclinical hypothyroidism (SCH) in improving well-being, cardiovascular outcomes, or mortality. We aimed to evaluate study procedures’ feasibility, safety, and preliminary effects of levothyroxine discontinuation in adults with SCH.</p> Methods <p>We conducted a pilot, double-blind, placebo-controlled RCT with 6-month follow-up at a Veterans Affairs Medical Center. Adults with SCH on levothyroxine ≤75 mcg daily were randomized to continue levothyroxine or switch to placebo. The primary outcome was feasibility.</p> Results <p>Fifty participants were randomized (32% enrollment rate); five were excluded post-randomization due to unconfirmed SCH, yielding 45 participants (21 levothyroxine, 24 placebo). One patient in the placebo group withdrew for personal reasons (98% completion rate). Participants’ mean age was 68.2 years (SD 9.7); 80% were male, and 86.7% were White. At 6 months, there was no statistically significant difference between the placebo and levothyroxine groups in ThyPRO-Hypothyroid Symptoms [28.3 (22.8) vs. 22.9 (19.5)], Tiredness [27.6 (22.8) vs. 32.8 (22.1)], and EQ-5D score [0.750 (0.232) vs. 0.741 (0.180)]. The only notable adverse event was rib fractures in a placebo group participant (TSH 3.04 mIU/L at 6 months). Two participants in the placebo group restarted levothyroxine (<i>n</i> = 1, TSH &gt; 10 mIU/L; <i>n</i> = 1, fatigue).</p> Conclusion <p>We demonstrated feasibility of study procedures for discontinuing levothyroxine in patients with SCH and obtained preliminary effects on well-being. The low occurrence of adverse events suggests that levothyroxine discontinuation may be well-tolerated. These findings support conducting a larger multi-site RCT to comprehensively assess the effects of levothyroxine discontinuation.</p> Clinical trial registration number <p><a href="https://clinicaltrials.gov/study/NCT04288115">NCT04288115</a></p>