Peptides for Ulcerative Colitis and Crohn's Disease: An IL-23 Pill in Phase 3, GLP-2 Drugs, and the BPC-157 Gap

Search for peptides and gut health, and most results promote BPC-157, a lab-made peptide sold online for "gut healing." For people with inflammatory bowel disease (IBD), the more useful news is a prescription pill. Icotrokinra, from Johnson & Johnson and Protagonist Therapeutics, is now in late-stage trials for both forms of IBD: ulcerative colitis, which inflames the lining of the colon, and Crohn's disease, which can affect any part of the digestive tract.

Icotrokinra is already sold as Icotyde for plaque psoriasis. The FDA approved it for that use on March 18, 2026, for patients aged 12 and older. Its IBD results are still investigational, and this guide separates what the trials have shown from what is still unknown. It also covers the gut peptides that are already approved and the evidence behind the gray-market options.

Treatment aims to calm inflammation and reach remission, which the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) describes as "a time when your symptoms disappear," and then keep it. Doctors choose among several drug groups: aminosalicylates, corticosteroids, immune-suppressing drugs, biologics, and newer small-molecule pills. Biologics are large protein drugs, mostly antibodies, made in living cells and given by injection or infusion. The pills include JAK inhibitors and ozanimod, a drug that keeps certain immune cells from leaving the lymph nodes.

One target has become central. IL-23 is an immune signaling protein that helps drive inflammation in the gut and the skin. Three antibodies that block it are approved in the U.S. for both forms of IBD. AbbVie's Skyrizi (risankizumab) became the first when it added ulcerative colitis on June 18, 2024. Lilly's Omvoh (mirikizumab), approved for ulcerative colitis in 2023, added Crohn's disease on January 15, 2025, and J&J's Tremfya (guselkumab) added Crohn's disease on March 20, 2025, after a 2024 approval in ulcerative colitis. All three start with an infusion or injection and continue as shots. Icotrokinra blocks the receptor that IL-23 binds to, and it is swallowed.

ANTHEM-UC enrolled 252 adults with moderately to severely active ulcerative colitis whose disease had not responded well enough to standard or advanced treatment, including biologics, ozanimod, or JAK inhibitors. Patients took 100, 200, or 400 mg of icotrokinra once a day, or a placebo.

J&J reported the 12-week results at United European Gastroenterology Week in October 2025. On the 400 mg dose, 63.5% of patients had a clinical response, the trial's main measure of improvement, compared with 27% on placebo. Clinical remission reached 30.2% versus 11.1%, and 36.5% versus 14.3% showed improvement on endoscopy, a camera exam of the colon. At week 28, presented at the American College of Gastroenterology meeting later that month, remission on the 400 mg dose was 31.7% versus 9.5% on placebo. The company said adverse events and serious adverse events occurred at similar rates on every dose and on placebo.

These are mid-stage results from company releases on a dose-finding trial. A Phase 2b trial can show that a drug is worth testing at scale, but it is too small to settle how well a drug works or how safe it is over years.

J&J started two larger programs in October 2025, according to ClinicalTrials.gov. ICONIC-UC, a Phase 3 trial that began on October 1, 2025, plans to enroll about 882 people with moderately to severely active ulcerative colitis, including an open-label group of adolescents aged 12 and older. Its main measures are clinical remission after 12 weeks of initial treatment and again after 40 weeks of maintenance. ICONIC-CD, a combined Phase 2b/3 trial in adults with Crohn's disease that began on October 3, 2025, plans to enroll about 1,092 people and measures both remission and healing seen on endoscopy.

The registry lists estimated primary completion dates of January 2028 for ICONIC-UC and September 2028 for ICONIC-CD. Until those trials report, icotrokinra remains investigational for IBD; its psoriasis approval rests on skin data.

Oral peptides for IBD can also fail. Protagonist's earlier pill, PN-943, targeted the same gut-homing pathway as the infused antibody Entyvio. In the Phase 2 IDEAL trial of 159 patients, reported in April 2022, the higher 450 mg twice-daily dose missed its main goal. The 150 mg dose produced 27.5% remission versus 14.5% on placebo, a difference that fell short of statistical significance. PN-943 no longer appears on Protagonist's pipeline page.

One group of gut peptides is already in use, mostly for a complication rather than for IBD itself. Short bowel syndrome happens when so much small intestine is missing or damaged that the body cannot absorb enough nutrients. The NIDDK says it most often follows surgery to remove part of the small intestine, and Crohn's disease is among the common reasons for that surgery in older children and adults. Many people with the condition depend on parenteral support, meaning nutrition and fluids given through a vein.

Teduglutide (Gattex), a copy of the gut hormone GLP-2, was first approved in the U.S. in 2012. It is now approved for adults and children aged 1 and older with short bowel syndrome who depend on parenteral support. In its main adult trial, 63% of patients on teduglutide (27 of 43) cut their weekly IV nutrition by at least 20%, compared with 30% on placebo (13 of 43). Crohn's disease was the reason for the original bowel surgery in 21% of those patients. Because GLP-2 makes gut tissue grow, the label warns that it may speed the growth of polyps and tumors and calls for a colonoscopy after one year of treatment.

Longer-acting GLP-2 drugs are in regulatory limbo. The FDA turned down Zealand Pharma's glepaglutide on December 19, 2024 and asked for another trial, which Zealand is running. In September 2026, a European Medicines Agency committee recommended approval of the drug as Zeydovio, citing a trial in which 65.7% of patients on twice-weekly dosing cut IV support by at least 20%, versus 38.9% on placebo. Ironwood said in May 2026 that it expected to begin opening sites in the second quarter for a confirmatory Phase 3 trial of apraglutide, its once-weekly GLP-2 drug.

Many people with IBD also have obesity, and some now take GLP-1 drugs such as semaglutide. A 2025 meta-analysis in the Journal of Crohn's and Colitis pooled 11 studies covering 16,242 people with IBD who used these drugs. Users had lower odds of IBD-related surgery (odds ratio 0.46), and people with a BMI of 30 or higher also had fewer hospital stays. All 11 studies were observational, so they cannot show that the drugs caused the better outcomes. The authors called for randomized trials in patients with active IBD. For now, a GLP-1 drug is a weight or diabetes treatment that a gastroenterologist may coordinate with IBD care, not a treatment for IBD.

BPC-157 has a large animal literature and only a few small human reports, none of which shows that it treats IBD. Our BPC-157 gut evidence review goes through those studies. On July 23, 2026, an FDA advisory committee voted 8 to 6, with one abstention, to recommend adding BPC-157 to the list of substances that compounding pharmacies may use. The vote was advice only. The FDA still has to decide whether to accept it and then complete a rulemaking process before pharmacies could legally prepare the peptide. Our explainer on the vote covers that process, and our guide to evaluating a compounding pharmacy covers what to check if you are offered a compounded peptide.

Larazotide shows how a gut peptide with a plausible mechanism can stall. It was designed to tighten the junctions between intestinal cells in celiac disease and became the first celiac drug to reach Phase 3. In June 2022, its developer, 9 Meters Biopharma, stopped the trial after an independent statistician found that it would need a substantial number of new patients to produce a clear answer. Our gut peptides overview covers larazotide, KPV, and other gut-focused peptides in more detail.

Bring these to your next visit:

• Could I qualify for a trial such as ICONIC-UC or ICONIC-CD? Both are listed on ClinicalTrials.gov with study sites.
• I am on an IL-23 antibody, or my doctor is considering one. How would a pill that blocks the same pathway compare, once trial data are available?
• If I have had bowel surgery and rely on IV nutrition, is a GLP-2 drug such as teduglutide an option, and what screening would I need?
• If I have obesity or type 2 diabetes, could a GLP-1 drug fit with my IBD treatment, and how would we watch for side effects such as nausea or slowed digestion?
• I am thinking about trying a supplement or a compounded peptide. What could it interact with, and what would you want me to report?

IBD treatment changes often, and the best choice depends on disease location, severity, past treatments, and coverage. Peptide news can help you ask better questions, but it cannot replace a gastroenterologist's review of your case.