Lipidated IL-22 Combined with GLP-1 Drug Achieves 40% Weight Loss While Preserving Muscle | Research

The takeaway

Long-acting lipidated IL-22 achieved 20% weight loss as monotherapy and 40% combined with GLP-1 RA in mice, preserving lean mass with less than half the muscle loss of GLP-1 drugs alone.

40% weight loss, muscle spared
Combining lipidated IL-22 with GLP-1 drug doubled weight loss while cutting lean mass loss by more than half

What the researchers found

Lipidated IL-22: 20% weight loss monotherapy, 40% with GLP-1 RA; <50% lean mass loss vs GLP-1 RA/caloric restriction; doubled fecal energy loss; increased PYY; normalized glucose independently of food intake.

Why it matters

GLP-1 drugs' two main limitations — insufficient weight loss and muscle loss — could both be addressed by adding lipidated IL-22.

How the study worked

Mouse obesity models treated with lipidated IL-22 alone or combined with GLP-1 RA, assessing body composition (lean vs fat mass), glycemic control, intestinal hormone secretion (PYY), and fecal energy content.

What this study cannot tell us

Mouse models only. IL-22 is an immunomodulatory cytokine; chronic use safety needs assessment. Human translation not established.

How to read the evidence

Preclinical study with comprehensive body composition and mechanistic analysis. Highly promising but needs human validation.

When this study was published

Published in 2025.

The bigger picture

Lipidated IL-22 addresses the two most important unmet needs in GLP-1 therapy: more weight loss and less muscle loss.

Questions still open

Would lipidated IL-22 + GLP-1 achieve similar results in humans?
What are the immune system effects of chronic IL-22 treatment?
Could lipidated IL-22 reduce the GLP-1 dose needed for target weight loss?

Common questions

Could this solve the muscle loss problem with GLP-1 drugs?

In mice, adding lipidated IL-22 to GLP-1 drugs cut muscle loss by more than half while doubling total weight loss. If this works in humans, it would address the biggest safety concern with current weight loss drugs.

How does IL-22 preserve muscle?

IL-22 works through the intestines to increase PYY (a satiety hormone) and reduce calorie absorption, achieving weight loss through a fundamentally different mechanism than GLP-1 drugs — one that preferentially burns fat rather than muscle.

Read the original research

Lipidated Interleukin-22 Reduces Body Weight And Spares Lean Mass In Mice By A Novel Gut Acting Mechanism Additive To GLP-1 Agonism.

Molecular therapy : the journal of the American Society of Gene Therapy

View on PubMed ↗Publisher’s paper ↗

Citation

Hass, Daniela; Madsen, Andreas N; da Silva-Buttkus, Patricia; Kjølbye, Anne Louise; Støy, Sidsel; Nøhr-Meldgaard, Jacob; Sandahl, Thomas D; Hrabě de Angelis, Martin; Jorgensen, Rasmus; Rohm, Maria; van de Bunt, Martijn. (2026). Lipidated Interleukin-22 Reduces Body Weight And Spares Lean Mass In Mice By A Novel Gut Acting Mechanism Additive To GLP-1 Agonism.. Molecular therapy : the journal of the American Society of Gene Therapy. https://doi.org/10.1016/j.ymthe.2026.02.041