GLP-1 Medicines and Psoriasis: What the Trials Show About Skin Plaques, Weight and Inflammation

Can GLP-1 medicines help psoriasis? In people who carry excess weight, the first large randomized trial says adding one to a standard psoriasis biologic clears more skin than the biologic alone. The smaller semaglutide and liraglutide studies point the same way, with one notable exception, and none of them tested GLP-1 drugs as a standalone psoriasis treatment.

Psoriasis is an immune-driven skin disease that causes thick, scaly plaques, most often on the elbows, knees, scalp and lower back. It affects at least 60 million people worldwide, and a 2026 Oxford meta-analysis notes that 80% of them also live with overweight or obesity. Fat tissue is metabolically active and produces inflammatory signals, which is why dermatologists have long suspected weight and psoriasis feed each other.

This article covers the TOGETHER-PsO and TOGETHER-PsA trials of tirzepatide, the small semaglutide and liraglutide studies, the weight-loss meta-analysis, the cohort data on heart and mortality outcomes, and what has not been studied, including low doses.

Can GLP-1 medicines help psoriasis? What TOGETHER-PsO found

Lebwohl and colleagues, JAMA Dermatology, 2026

Adding tirzepatide to the psoriasis biologic ixekizumab cleared more skin and took off far more weight than ixekizumab alone. TOGETHER-PsO, led by Mark Lebwohl at Mount Sinai, was a phase 3b, open-label trial at 72 US sites. It randomized 274 adults with moderate to severe plaque psoriasis and overweight with a weight-related condition, or obesity, 1:1 to the two strategies, with diet and exercise advice in both arms.

These were people with substantial disease. The average screening BMI was 39.2, the average PASI (Psoriasis Area and Severity Index, the standard severity score) was 19.7, and participants had lived with psoriasis for 14.6 years on average. The trial authors note that overweight and obesity affect 60% to 78% of people with psoriasis.

At week 36, 27.1% on the combination reached both PASI 100 (completely clear skin) and at least 10% weight loss, against 5.8% on ixekizumab alone. Looking at skin alone, 40.6% versus 29.0% reached PASI 100 (P = .04). The gap on weight was much wider: 69.2% versus 9.1% lost 10% or more. Gastrointestinal side effects were more common with the combination. Several authors are employees of Eli Lilly, which makes both drugs, and the open-label design means participants knew which arm they were in.

Do GLP-1 drugs help psoriatic arthritis too?

Merola and colleagues, Arthritis & Rheumatology, 2026

The sister trial in psoriatic arthritis found the same add-on pattern for joints. TOGETHER-PsA randomized 271 adults with active psoriatic arthritis and overweight or obesity to ixekizumab plus tirzepatide (138 people) or ixekizumab alone (133), both at US-approved doses. Overweight or obesity is present in 72% to 82% of people with psoriatic arthritis, according to the authors.

The primary goal combined a 50% improvement in American College of Rheumatology response criteria (ACR50) with at least 10% weight loss at 36 weeks. It was reached by 31.7% on the combination and 0.8% on ixekizumab alone. On joints alone, ACR50 rates were 33.5% versus 20.4%. Fatigue and physical function scores also improved more with the combination. Like TOGETHER-PsO, the trial was sponsored by Eli Lilly.

Does semaglutide improve psoriasis?

Petković-Dabić 2025 and Nicolau 2026

Two small studies suggest semaglutide improves psoriasis in people with obesity, but neither was blinded. In an open-label randomized trial from Banja Luka, Jelena Petković-Dabić and colleagues gave 31 people with psoriasis, obesity and type 2 diabetes on metformin either semaglutide (15 people) or no added drug (16) for 12 weeks.

In the semaglutide group, median PASI fell from 21 to 10, and the median Dermatology Life Quality Index (DLQI) score fell from 14 to 4, a large change in how much the skin disrupted daily life. Blood levels of the inflammatory markers interleukin-6 and C-reactive protein dropped as well. Our article on GLP-1s and CRP covers what that marker does and does not tell you.

A Spanish prospective cohort led by Joana Nicolau followed 43 people with psoriasis and obesity, without diabetes, on weekly semaglutide plus lifestyle advice for 6 months. PASI fell by 48%. The most interesting detail was which change tracked skin improvement best: loss of superficial fat under the skin (r = 0.89), while BMI change was no longer significantly linked once the analysis was adjusted. There was no control group.

Why did one placebo-controlled trial find no effect?

Faurschou and colleagues, JEADV, 2015

The only placebo-controlled GLP-1 psoriasis trial in people without diabetes was small, short and negative. Anne Faurschou and colleagues in Copenhagen randomized 20 glucose-tolerant adults with obesity and plaque psoriasis (PASI of at least 8) to daily liraglutide or placebo for 8 weeks.

PASI fell by 2.6 points on liraglutide and 1.3 points on placebo, and the difference was not statistically significant (P = 0.228). Quality of life scores and hsCRP did not differ either. Weight did move: 4.7 kg lost on liraglutide against 1.6 kg on placebo. Nausea affected 45% of people on liraglutide and none on placebo; our guide to GLP-1 nausea explains why it clusters early.

Eight weeks is a short window for a skin disease that changes slowly, and 20 people is too few to detect a modest effect. Still, this is the cleanest blinded test available outside diabetes, and it did not show a direct skin benefit. It is a useful check on the more enthusiastic uncontrolled reports.

Is the psoriasis benefit just from losing weight?

Morrow and colleagues, JEADV, 2026

Weight loss by any method improves psoriasis, so a large share of the GLP-1 effect is likely the weight itself. Sarah Morrow and colleagues at Oxford pooled 13 randomized trials with 1145 participants that compared a weight-loss intervention with usual care or a lighter program. Most used diet changes; three used weight-loss medicines.

With an average extra weight loss of 6.7 kg, PASI fell 2.5 points more than in controls, and people were more likely to reach PASI 75 (relative risk 1.6). Quality of life improved by 5.0 DLQI points. Results for PASI 50 and PASI 100 pointed the same way but were not statistically significant, partly because few trials reported them. The authors rated the overall evidence as high certainty and said weight loss should be part of routine psoriasis care.

That does not settle whether GLP-1 drugs add anything beyond weight. The Nicolau cohort's link with superficial fat rather than BMI hints that where fat comes off may matter, and our explainer on visceral vs subcutaneous fat covers that distinction. Laboratory work suggests direct immune effects too, but no trial has separated the two cleanly.

Do GLP-1 drugs change heart and mortality risk in psoriasis?

Olbrich and colleagues, British Journal of Dermatology, 2026

Health record data link GLP-1 drug use in psoriasis to lower death and heart event rates, but the data are observational. Henning Olbrich and colleagues used the US TriNetX network to compare people with psoriasis who took a GLP-1 drug for diabetes or obesity with people on other antidiabetic or antiobesity medicines, matching 3048 people in each group.

Over 2 years, GLP-1 use was associated with lower all-cause death (hazard ratio 0.219) and fewer major adverse cardiac events (hazard ratio 0.561), plus lower rates of alcohol and substance abuse. Typical drug side effects were not more frequent. A drop in deaths this steep is larger than randomized heart trials have shown in other groups, which suggests some of it reflects who gets prescribed a newer drug rather than the drug alone.

What do psoriasis specialists say about GLP-1 drugs?

National Psoriasis Foundation primer, JAMA Dermatology, 2026

The US National Psoriasis Foundation's medical board supports considering GLP-1 drugs as an add-on in selected patients with metabolic conditions, while waiting for larger trials. Its 2026 primer in JAMA Dermatology, led by Sheth, summarised reports of relative PASI reductions of roughly 40% to 80%, but noted most come from studies of 7 to 48 patients, lasting 6 months or less, without a control group.

The primer states that GLP-1 drugs combine safely with methotrexate, cyclosporine and biologics, and that side effects are mainly short-lived gastrointestinal symptoms, with pancreatitis and gallbladder problems rare. Psoriasis often travels with other inflammatory skin conditions; our article on GLP-1 drugs and hidradenitis suppurativa covers a related evidence base.

Does microdosing a GLP-1 help psoriasis?

What the evidence can and cannot support

No study has tested low GLP-1 doses for psoriasis. TOGETHER-PsO and TOGETHER-PsA used US-approved tirzepatide doses, and the semaglutide and liraglutide studies used standard treatment regimens. None reported results by dose level.

The weight-loss meta-analysis gives a reason to think steady weight loss of any kind helps skin, and the semaglutide cohort hints that the type of fat lost matters. Neither tells us whether a smaller dose, with slower and smaller weight change, would move PASI scores in a meaningful way.

The practical summary is narrow. In people with psoriasis and excess weight, adding tirzepatide to a biologic produced more clear skin and much more weight loss in one industry-run trial. Smaller studies are mixed. GLP-1 drugs are not psoriasis treatments on their own, and anyone with psoriasis or joint symptoms should plan any change with their dermatologist or rheumatologist.

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