VK2735: Viking Therapeutics' Dual GIP/GLP-1 Obesity Drug
VK2735 produced up to 14.7% weight loss in just 13 weeks, as both a weekly shot and a daily pill. How Viking Therapeutics' dual GIP/GLP-1 drug works.
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Reviewed by Dr. James Chen, MD, PhD, FACE on June 7, 2026
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Most obesity drugs that reach phase 2 report their headline weight-loss figure after a year or more on treatment. VK2735, the dual GIP/GLP-1 receptor agonist from Viking Therapeutics, hit 14.7% mean body weight reduction in just 13 weeks — and the weight-loss curve was still falling when the trial ended. That short timeline, paired with the fact that VK2735 is advancing as both a weekly injection and a daily tablet, is why it has become one of the most closely watched candidates in the obesity pipeline.
The number alone puts VK2735 in conversation with tirzepatide, the only approved drug that uses the same two-receptor mechanism. But a 13-week phase 2 readout and a 72-week phase 3 program are very different things. Here is what the published evidence actually shows, how the injectable and oral forms differ, and where the open questions sit.
What Is VK2735?
VK2735 is a single peptide engineered to activate two gut-hormone receptors at once: the glucagon-like peptide-1 (GLP-1) receptor and the glucose-dependent insulinotropic polypeptide (GIP) receptor. Both receptors sit on neurons in the brain's appetite-regulating centers, and both influence insulin secretion and gut motility. Hitting them together suppresses appetite and slows gastric emptying more powerfully than engaging GLP-1 alone.
That dual-agonist design is the same strategy behind tirzepatide. It is worth distinguishing it from a different bet in the field: MariTide pairs GLP-1 agonism with GIP antagonism — the opposite action at the GIP receptor. Both approaches produce strong weight loss in trials, which is part of why GIP pharmacology remains an active scientific debate. VK2735 lands firmly on the agonist side of that question.
Evidence: "Dual GIP/GLP-1 receptor agonists demonstrated superior weight-reduction efficacy, with tirzepatide producing placebo-corrected weight loss of 17.8% in patients without diabetes versus 12.4% for semaglutide, suggesting the combined mechanism produces more robust weight loss than GLP-1 monotherapy alone." — Liu QK. Front Endocrinol. 2024. 10.3389/fendo.2024.1431292
Viking Therapeutics is a clinical-stage biotech with no products yet on the market, so VK2735's entire profile rests on early- and mid-stage trial data rather than years of post-approval use. That distinction matters when weighing the results below.
What the VENTURE Trial Showed
The pivotal mid-stage evidence comes from VENTURE, a phase 2, randomized, double-blind, placebo-controlled study of weekly subcutaneous VK2735 published in Obesity in 2026. The trial enrolled 176 adults with obesity (BMI ≥ 30) or overweight (BMI ≥ 27) plus at least one weight-related comorbidity, and it excluded people with type 2 diabetes. Participants were randomized across four active doses — 2.5, 5, 10, and 15 mg once weekly — or placebo, and treated for 13 weeks.
Evidence: "After 13 weeks of weekly subcutaneous dosing, mean body weight reductions reached 14.7% at the highest dose, with placebo-subtracted reductions of up to 13.1% and no weight-loss plateau observed." — Bays HE, et al. Obesity. 2026. 10.1002/oby.70106
Every active dose separated from placebo with high statistical significance (p < 0.0001), and the response scaled cleanly with dose.
| Dose (weekly SC) | Mean weight loss | Placebo-subtracted | ≥10% weight loss | ≥15% weight loss |
|---|---|---|---|---|
| Placebo | −1.7% | — | 3.0% | 0% |
| 2.5 mg | −9.1% | −7.4% | 40.1% | 12.8% |
| 5.0 mg | −10.9% | −9.2% | 65.1% | 11.6% |
| 10 mg | −12.9% | −11.3% | 70.4% | 31.2% |
| 15 mg | −14.7% | −13.1% | 89.1% | 41.5% |
The detail that drew the most attention was the trajectory. At 13 weeks, weight was still declining — there was no flattening of the curve. A 14.7% loss in roughly three months, with momentum intact, is what fuels the comparison to approved drugs that take 16 to 18 months to reach similar territory. The caveat is the mirror image of that excitement: a curve that has not plateaued tells you nothing definitive about where it lands at week 52 or 72. Extrapolation is not data.
The Oral Tablet Running in Parallel
VK2735 is unusual in that Viking is developing an oral tablet alongside the injection, similar to the dual-formulation strategy seen with oral GLP-1 pills now entering the market. At the 2026 European Congress on Obesity, the company presented 13-week data from VENTURE-Oral, a phase 2 dose-ranging study of the tablet in 280 adults across once-daily doses from 15 to 120 mg.
The top oral dose produced 12.2% mean weight loss at 13 weeks. At that dose, 80% of participants lost at least 10% of body weight and 97% lost at least 5%, versus 5% and 10% on placebo. The gastrointestinal side-effect pattern matched the injection, and the company reported that 98% of drug-related adverse events were mild or moderate.
One important qualifier: the oral results are conference-presentation data, not yet published in a peer-reviewed journal. They are promising and internally consistent with the injectable findings, but they carry less evidentiary weight than the VENTURE paper until a full manuscript appears. A pill that delivers double-digit weight loss without the storage, needle, and titration logistics of an injection would matter commercially — but that case still has to clear peer review and a phase 3 trial.
How VK2735 Compares to Approved Drugs
Cross-trial comparisons are imperfect — different durations, populations, and endpoints — so the table below is a rough orientation, not a head-to-head result. The approved drugs report 68- to 72-week figures; VK2735 reports 13-week figures.
| Drug | Mechanism | Trial | Mean weight loss | Duration |
|---|---|---|---|---|
| VK2735 (SC) | GIP/GLP-1 agonist | VENTURE | 14.7% | 13 weeks |
| Tirzepatide | GIP/GLP-1 agonist | SURMOUNT-1 | 20.9% | 72 weeks |
| Semaglutide | GLP-1 agonist | STEP 1 | 14.9% | 68 weeks |
For context on the established benchmarks:
Evidence: "Tirzepatide once weekly produced mean weight reductions of 15.0%, 19.5%, and 20.9% at the 5-mg, 10-mg, and 15-mg doses over 72 weeks." — Jastreboff AM, et al. NEJM. 2022. 10.1056/NEJMoa2206038
Evidence: "Once-weekly semaglutide 2.4 mg produced a mean change in body weight of −14.9% at week 68, compared with −2.4% for placebo." — Wilding JPH, et al. NEJM. 2021. 10.1056/NEJMoa2032183
The head-to-head SURMOUNT-5 trial later confirmed that the dual-agonist mechanism outperforms GLP-1 alone over a full treatment course, with tirzepatide producing roughly 20% mean weight loss versus about 14% for semaglutide.
Evidence: "Tirzepatide was superior to semaglutide with respect to the percentage change in body weight at week 72 (−20.2% vs. −13.7%)." — Aronne LJ, et al. NEJM. 2025. 10.1056/NEJMoa2416394
Reading these together, VK2735's 13-week figure is genuinely strong for the time elapsed, and its mechanism class has already proven it can reach the ~20% tier given enough time. Whether VK2735 specifically gets there depends entirely on longer trials that have not yet read out.
Safety and Tolerability
The side-effect profile in VENTURE was what the GLP-1 class has trained clinicians to expect: predominantly gastrointestinal, dose-related, concentrated early in treatment, and easing with continued use.
| Adverse event | Frequency |
|---|---|
| Nausea | 36.6% |
| Constipation | 21.1% |
| Vomiting | 12.6% |
Most GI events were graded mild or moderate, with no severe (grade 4 or 5) cases reported. Roughly 8.5% of participants discontinued treatment because of adverse events, and overall study completion was about 95%. Those discontinuation numbers are broadly in line with what the established GLP-1 medications show in their own trials, though only longer studies in larger populations will reveal whether VK2735's tolerability holds up at the higher doses needed for maximal weight loss.
What the 13-week data cannot yet address is the slower-moving safety questions that only emerge over a year or more: lean-mass loss, gallbladder events, pancreatitis signals, and the durability of weight maintenance. None of these are red flags for VK2735 specifically — they are simply unanswered, because the trial was too short to answer them.
What Comes Next
VK2735 sits at the transition point where most obesity candidates either prove themselves or stall: the move from phase 2 to phase 3. Viking has outlined a phase 3 program for the subcutaneous formulation and is advancing the oral tablet behind it. The questions that program needs to answer are concrete:
- Does the 13-week trajectory hold? A non-plateauing curve at three months is encouraging, but the field is littered with drugs that looked steeper early and converged later.
- How does it tolerate at scale? Phase 3 populations are larger, more diverse, and treated longer — the truest test of the GI profile.
- Does weight stay off? Like every drug in this class, VK2735 will face the weight-regain question once treatment stops.
- What about cardiometabolic outcomes? The class has raised the bar beyond the scale, and a competitive obesity drug increasingly needs outcome data to match.
For now, VK2735 is a phase 2 asset with a striking early signal and two viable formulations — not an approved therapy. The data justify the attention, but the verdict belongs to trials that have yet to report.
Key Takeaways
- VK2735 is a dual GIP/GLP-1 receptor agonist — the same mechanism as tirzepatide, distinct from MariTide's GIP-antagonist approach.
- The phase 2 VENTURE trial showed up to 14.7% weight loss in 13 weeks at the 15 mg weekly subcutaneous dose, with no plateau and high statistical significance.
- An oral tablet is advancing in parallel, with about 12.2% weight loss at 13 weeks in conference-presented data that is not yet peer-reviewed.
- Tolerability mirrored the GLP-1 class — mostly mild-to-moderate GI effects, with an ~8.5% adverse-event discontinuation rate.
- It remains an investigational drug. Viking has no approved products, and the decisive evidence — long-duration phase 3 efficacy, safety, and durability — does not yet exist.
References
- Bays HE, et al. Weekly Subcutaneous VK2735, a GIP/GLP-1 Receptor Dual Agonist, for Weight Management: Phase 2, Randomized, 13-Week VENTURE Study. Obesity. 2026;34(3):537-549. DOI: 10.1002/oby.70106 — PMID: 41508550
- Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med. 2022;387(3):205-216. DOI: 10.1056/NEJMoa2206038
- Wilding JPH, Batterham RL, Calanna S, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity. N Engl J Med. 2021;384(11):989-1002. DOI: 10.1056/NEJMoa2032183
- Aronne LJ, Jastreboff AM, Hartman ML, et al. Tirzepatide as Compared with Semaglutide for the Treatment of Obesity. N Engl J Med. 2025. DOI: 10.1056/NEJMoa2416394 — PMID: 40353578
- Liu QK. Mechanisms of action and therapeutic applications of GLP-1 and dual GIP/GLP-1 receptor agonists. Front Endocrinol. 2024;15:1431292. DOI: 10.3389/fendo.2024.1431292
Last updated: 2026-06-07 Medical review: Dr. James Chen, MD, PhD, FACE
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Written By
Dr. Sarah Mitchell
Medical Director, MD, FACP
Dr. Sarah Mitchell is a board-certified internist specializing in metabolic medicine and weight management. With over 15 years of clinical experience, she has helped thousands of patients achieve sustainable weight loss through evidence-based approaches.
Medical Reviewer
Dr. James Chen
Endocrinologist, MD, PhD, FACE
Dr. James Chen is a fellowship-trained endocrinologist with expertise in diabetes, metabolism, and hormone-related weight disorders. His research on GLP-1 receptor agonists has been published in leading medical journals.
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