The First Large Trial Testing a GLP-1 Drug for Long COVID Just Finished Enrolling—in Under Two Months

Scripps Research’s LoCITT-T trial recruited 1,000 Long COVID patients to test tirzepatide. No FDA-approved treatments for the condition exist.

Scripps Research Translational Institute has completed enrollment for LoCITT-T, a Phase 2 clinical trial testing whether tirzepatide—the dual GIP/GLP-1 receptor agonist sold as Mounjaro and Zepbound—can alleviate Long COVID symptoms. The trial recruited all 1,000 participants in fewer than two months. That enrollment speed tells its own story: there are no FDA-approved treatments for Long COVID, and patients are desperate enough to sign up for an obesity drug repurposed on a mechanistic hypothesis.

What the Trial Is Testing

LoCITT-T is a fully remote, placebo-controlled trial—part of the broader Long COVID Treatment Trial (LoCITT) platform funded by the Schmidt Initiative for Long COVID (SILC). The primary hypothesis is that tirzepatide can reduce Long COVID symptoms by targeting neuroinflammation. GLP-1 receptor agonists have demonstrated anti-inflammatory properties beyond their metabolic effects, and tirzepatide’s dual-receptor mechanism (GIP + GLP-1) may offer broader anti-inflammatory coverage than semaglutide alone.

Secondary endpoints include improvements in hyperglycemia, blood pressure, weight, and oxidative stress—all of which are elevated in many Long COVID patients. The trial’s fully remote design (no in-person visits required) enabled the rapid enrollment by removing geographic barriers.

Why This Matters

Three reasons this trial deserves attention.

It’s the first large-scale RCT of a GLP-1 drug for Long COVID. Anecdotal reports of GLP-1 agonists improving Long COVID symptoms have circulated in patient communities for over a year. This trial is the first to test the hypothesis rigorously with a placebo control and adequate sample size.

The enrollment speed signals unmet need, not drug enthusiasm. One thousand patients in under eight weeks, for a fully remote trial with no guaranteed benefit, is extraordinary. It reflects the severity of the Long COVID treatment vacuum—an estimated 6–7% of U.S. adults report current Long COVID symptoms, and they have essentially nothing to take for it.

Positive results would expand tirzepatide’s clinical story significantly. Tirzepatide is currently approved for type 2 diabetes (Mounjaro) and obesity (Zepbound). If LoCITT-T demonstrates symptom relief in Long COVID, it would be the first evidence-based treatment for the condition and would fundamentally change how we understand tirzepatide’s clinical profile—adding an entirely new indication supported by controlled data.

What We Don’t Know Yet

Results have not been reported. The trial is underway, and a timeline for data readout has not been publicly disclosed. It is also important to note that Long COVID is a heterogeneous condition—what works for neuroinflammation-driven symptoms may not address other Long COVID phenotypes (cardiovascular, respiratory, dysautonomic). A single positive trial, even a well-designed one, would be a starting point, not a conclusion.

Peptidings will cover the results when they are published.