Review of GLP-1 Receptor Agonists in Psoriasis Save

Know-it-now:

• GLP-1 RAs are not FDA-approved for psoriasis, but observational and trial data consistently show meaningful reductions in PASI scores — particularly in obese patients — likely through weight loss, adipose-driven inflammation reduction, and possible direct anti-inflammatory signalling.
• Obesity is a major driver of psoriasis severity and biologic non-response; GLP-1 RAs may address this directly
• Tirzepatide (dual GIP/GLP-1) appears to achieve the greatest weight reduction (16–24% in non-diabetic patients)
• GLP-1 RAs may reduce or enable tapering of systemic immunosuppressants (including methotrexate and biologics) in patients who achieve significant weight loss, reducing cumulative toxicity.
• GI side effects (nausea, vomiting, diarrhoea) are the most common reason for discontinuation
• Rheumatologists managing psoriatic arthritis patients with obesity should co-manage with dermatologists or endocrinologists.

Psoriasis is a chronic immune-mediated inflammatory disease plaqued by systemic comorbidities that increase morbidity, mortality, and treatment complexity. Obesity is a significant contributor to psoriatic disease.

The advent of incretin therapy may substantially alter the course of psoriasis and psoriatic arthritis.  Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have transformed cardiometabolic medicine and are now attracting intense interest in inflammatory disorders. This National Psoriasis Foundation primer, published in JAMA Dermatology, provides dermatologists and rheumatologists with a practical framework for understanding GLP-1 RA pharmacology, their landmark cardiovascular, metabolic, and organ-protection trial data, the emerging evidence base for psoriasis-specific benefit, and a clinical guide to agent selection, dosing, and safety monitoring in patients with psoriasis.

Psoriasis affects approximately 3% of the global population and is now firmly recognised as a systemic inflammatory disease. Patients carry a substantially elevated burden of cardiometabolic comorbidity: obesity (prevalent in ~30–40%), metabolic syndrome, type 2 diabetes, non-alcoholic/metabolic steatohepatitis (MASH), obstructive sleep apnoea, and major adverse cardiovascular events (MACE). Adipose tissue functions as an active immunological organ in psoriasis, secreting pro-inflammatory adipokines (leptin, resistin, adiponectin dysregulation) and amplifying the IL-17/IL-23 and TNF-α axes that drive skin disease.

Obesity is reduces biologic efficacy, increases disease severity, and is independently associated with psoriatic arthritis risk. Weight-based dosing challenges, accelerated drug clearance, and adipose-driven immune activation all conspire to undermine therapeutic response. This pathophysiological intersection positions GLP-1 RAs — agents that reduce adipose-driven inflammation while producing significant weight loss — as uniquely suited adjuncts in the psoriasis population.

GLP-1 RA Pharmacology 

GLP-1 is an incretin hormone secreted from intestinal L-cells in response to nutrient ingestion. Endogenous GLP-1 has a plasma half-life of under two minutes; GLP-1 RAs are synthetic analogues engineered for prolonged receptor engagement. They act on GLP-1 receptors in the pancreas (insulin secretion, glucagon suppression), hypothalamus (appetite suppression via POMC/NPY pathways), gastric smooth muscle (delayed emptying), and peripheral tissues including adipose and immune cells.

The FDA-approved GLP-1 RA landscape encompasses single-agonists and the dual GIP/GLP-1 agonist tirzepatide. Agents with direct relevance to the psoriasis-comorbidity matrix include:

• Semaglutide SC (Ozempic/Wegovy): The most studied agent in cardiovascular and metabolic outcomes. Wegovy (2.4 mg/wk) achieves ~15% weight loss in non-diabetic patients; the SELECT trial demonstrated a 20% MACE reduction in non-diabetic patients with obesity and established CVD.
• Tirzepatide SC (Mounjaro/Zepbound): Dual GIP/GLP-1 agonism produces the greatest weight reduction among approved agents — up to 20–24% in non-diabetic patients (SURMOUNT-1). The SYNERGY-NASH trial showed 74% MASH resolution vs 13% for placebo.
• Liraglutide SC (Victoza/Saxenda): Daily dosing; 5–8 kg weight loss; the LEADER trial showed cardiovascular benefit in high-risk diabetic patients. Less potent than semaglutide/tirzepatide.
• Dulaglutide SC (Trulicity): Weekly dosing; moderate weight loss (2–5 kg); the REWIND trial showed CV benefit including in primary prevention populations.

Mechanisms of Benefit

• Weight Loss–Mediated: The predominant proposed mechanism is indirect: weight loss reduces adipose-derived pro-inflammatory cytokine secretion, lowers systemic IL-6, TNF-α, and IL-17 levels, improves insulin sensitivity, and reduces the immunological "noise" that drives psoriatic inflammation. Weight loss of ≥10% has been associated with significant PASI improvements independent of concomitant biologic use in observational cohort data.
• Immune Modulation: GLP-1 receptors are expressed on dendritic cells, macrophages, and T-lymphocytes. Preclinical and early human data suggest GLP-1 RA signalling can suppress NF-κB–driven cytokine production, reduce macrophage M1 polarisation, and attenuate Th17 differentiation — all pathways central to psoriatic disease. Whether this direct immunomodulation is clinically significant independent of weight loss remains an active area of investigation.

Clinical Evidence in Psoriasis

No GLP-1 RA is currently FDA-approved for psoriasis. Existing data derive from secondary analyses of metabolic trials, retrospective cohort studies, and small prospective analyses. Collectively, the evidence shows:

• PASI score improvements of 20–75% have been reported in psoriasis patients on GLP-1 RAs, most pronounced in those achieving >10% body weight reduction.
• A retrospective analysis of semaglutide-treated patients with co-existing psoriasis (n=~200) demonstrated PASI 75 responses in approximately 45% — rates approaching those seen with conventional systemic therapies in this obese subpopulation.
• The SURMOUNT-1 subgroup with skin disease showed numerical improvements in dermatologist-assessed psoriasis severity with tirzepatide vs placebo.
• Biologic-naïve obese patients appear to derive the greatest benefit, while those already on IL-17 or IL-23 inhibitors show more modest additive effects, consistent with a predominantly weight-loss–mediated mechanism.
• Data in psoriatic arthritis are even more limited; improvements in swollen/tender joint counts have been reported anecdotally, likely mediated by weight reduction reducing mechanical and inflammatory joint load.

Ideal candidates are psoriasis patients with BMI ≥30 (or ≥27 with comorbidity), particularly those with suboptimal biologic response, metabolic syndrome, type 2 diabetes, established CVD, or MASH. The agent selection should be driven by dominant comorbidity: semaglutide for CVD/CKD, tirzepatide for maximum weight loss or MASH, liraglutide if weekly agents are unavailable.

Class-wide contraindications include personal or family history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia type 2 (MEN2) — GLP-1 receptors are expressed on C-cells. Additional cautions include active or history of pancreatitis, severe gastroparesis, and severe GI dysmotility. Psoriasis-specific safety signals have not been identified; importantly, these agents do not cause immunosuppression and carry no increased infectious risk relevant to biologic-combination scenarios.

GI events are universal early in therapy: nausea occurs in 30–50%, vomiting in 15–25%, diarrhea in 20–30%, and constipation in 10–20%. These are typically transient, peak during titration, and are substantially mitigated by slow dose escalation over 16–20 weeks. Gallbladder disease (cholelithiasis, cholecystitis) occurs at elevated rates vs placebo across all agents. Rare pancreatitis cases have been reported. Muscle mass loss accompanying rapid weight reduction is a practical concern, particularly in older patients; resistance exercise during GLP-1 therapy is advised. Possible exacerbation of diabetic retinopathy with rapid HbA1c correction (semaglutide) warrants baseline retinal screening in diabetic patients.

However, current evidence on GLP-1 agents is largely observational and hypothesis-generating. Rheumatologists and dermatologists are encouraged to co-manage GLP-1 RA prescribing in appropriate psoriasis patients, particularly in the context of psoriatic arthritis with metabolic comorbidity, while awaiting the RCT evidence that will definitively establish their role in psoriasis-specific treatment algorithms.