New reviews link semaglutide and liraglutide to psoriasis improvements

Two 2026 reviews pull together evidence that GLP-1 receptor agonists may reduce psoriasis severity in people who also have obesity or type 2 diabetes, while agreeing that the drugs' role in skin care is not settled ^[1][2].

A narrative review in Frontiers in Immunology, written by researchers at the University of Modena and Reggio Emilia and the University of Ferrara in Italy, focused on liraglutide and semaglutide in people with psoriasis plus type 2 diabetes or obesity ^[1]. In one randomized trial of 25 people with psoriasis and type 2 diabetes, those assigned to liraglutide 1.8 mg a day had greater reductions in Psoriasis Area and Severity Index (PASI) scores than controls on conventional therapy, along with significant decreases in skin levels of interleukin-17, interleukin-23 and tumor necrosis factor alpha ^[1]. An open-label randomized trial of semaglutide 1 mg a week in 31 people with psoriasis and type 2 diabetes reported significant reductions in interleukin-6 and C-reactive protein alongside improvements in PASI, body mass index and LDL cholesterol ^[1]. Skin improvements appeared at least partly independent of weight loss, the authors said, pointing toward direct immune effects ^[1].

A separate primer from the National Psoriasis Foundation Medical Board, published in JAMA Dermatology on April 29, 2026, reports PASI reductions of roughly 40% to 80% across prior research in people with psoriasis and obesity and/or type 2 diabetes, but says results may depend on how much metabolic dysfunction a patient has at the start ^[2]. It summarized three randomized trials with conflicting results. In the only placebo-controlled one, 20 people with obesity and plaque psoriasis received liraglutide 1.8 mg daily or placebo for eight weeks; the liraglutide group lost more weight (-4.7 kg vs -1.6 kg; P = .01) but did not show a significant PASI reduction (-2.6 vs -1.3; P = .23) ^[2]. In an open-label trial of 31 people with obesity, psoriasis and type 2 diabetes taking metformin, 12 weeks of semaglutide cut PASI by 52% (median 21.0 to 10.0; P = .002) and improved Dermatology Life Quality Index, BMI, LDL cholesterol and C-reactive protein ^[2]. A third open-label trial of 24 people with type 2 diabetes and psoriasis taking acitretin found daily liraglutide 1.8 mg lowered PASI by 83% (mean 14.0 to 2.4; P < .05) and reduced interleukin-23 and interleukin-17 levels ^[2].

Cohort data point the same direction. In a six-month study of 43 people with psoriasis and obesity but no diabetes who took semaglutide, PASI fell 48% (mean 10.6 to 5.5; P < .001) ^[2]. Five small liraglutide studies reported PASI reductions from 23% to 85% ^[2].

Both reviews stress the limits. Samples were small, some studies had no control group, follow-up was short, and most participants had obesity or type 2 diabetes, which limits what the findings mean for other patients with psoriasis ^[1][2]. The Frontiers review was narrative rather than systematic, so it could not draw formal meta-analytic conclusions, and separating weight-loss effects from direct anti-inflammatory effects remains difficult ^[1]. Only one clinical study has directly evaluated a GLP-1 drug in psoriatic arthritis: 10 adults with obesity and psoriatic arthritis who took liraglutide 3 mg a day, with improvements in minimal disease activity scores, BMI, waist circumference, blood sugar, lipids and C-reactive protein ^[1]. Disease duration was not reported, and those participants were not characterized as having early psoriatic arthritis ^[1]. No published study has specifically targeted early psoriatic arthritis, which the review called a critical gap ^[1].

On safety, the primer says skin reactions to GLP-1 drugs are uncommon but include bullous pemphigoid, eosinophilic panniculitis, morbilliform eruptions, fixed drug eruptions and dermal hypersensitivity ^[2]. Injection-site reactions occur in fewer than 5% to 30% of patients and usually ease within three to four weeks ^[2]. Some research reports hair loss at higher rates with tirzepatide than placebo (relative risk 5.67; 95% CI 2.47-13.00), though that evidence is limited ^[2]. GLP-1 drugs may slightly raise the risk of immune-mediated diseases including psoriasis (hazard ratio 1.17; 95% CI 1.12-1.22), with a modest absolute increase ^[2].

Andrew Blauvelt, MD, MBA, medical board chair of the National Psoriasis Foundation, said the drugs are not meant to treat psoriasis itself. "GLP-1 RA use is not for the treatment of psoriasis per se; it's for the treatment of obesity and overweight, which influences the response of the psoriasis drugs," he said, adding that "the primary psoriasis drugs work better when patients are thinner" ^[2]. He also said the foundation does not expect GLP-1 drugs to match standard psoriasis drugs alone, and advocates using them alongside them ^[2].

Why it matters for patients

GLP-1 medications are not FDA-approved for psoriasis or psoriatic arthritis, and the primer notes that insurance coverage may be limited for that reason ^[2]. The primer states that GLP-1 therapies can cost more than $7,000 a year, and that value is likely greatest for patients who also have obesity or type 2 diabetes ^[2].

For patients already on these drugs for diabetes or weight loss, the reviews suggest skin and inflammation markers may improve, but they do not establish that the drugs work in psoriasis patients without metabolic conditions ^[1][2]. The primer recommends that dermatologists record the specific drug, dose, titration schedule and prescriber, plus baseline and follow-up weight, BMI, HbA1c, fasting glucose, lipids and psoriasis measures, and review those every three to six months ^[2]. It advises prescribing only FDA-approved products rather than compounded versions, and says microdosing lacks evidence ^[2]. It also states that GLP-1 drugs can be co-administered with methotrexate, cyclosporine and biologic agents ^[2].

What happens next

Two ongoing trials, TOGETHER-PsA (NCT06588296) and TOGETHER AMPLIFY-PsA (NCT06864026), are testing ixekizumab with and without tirzepatide in people with active psoriatic arthritis who have overweight or obesity ^[1]. Completion dates have not been reported. The Frontiers review calls for future studies in early psoriatic arthritis, with metabolic phenotyping and long-term data on cardiovascular and musculoskeletal outcomes, and for research into combining GLP-1 drugs with established biologics ^[1].