VK2735 is an investigational weight-loss drug from Viking Therapeutics. It is a peptide that activates two gut-hormone receptors at once: the glucagon-like peptide-1 (GLP-1) receptor and the glucose-dependent insulinotropic polypeptide (GIP) receptor. That is the same dual mechanism as tirzepatide (Mounjaro, Zepbound), while semaglutide and the oral small molecule orforglipron act on the GLP-1 receptor only.
Viking is developing the same molecule in two forms: a once-weekly injection under the skin and a once-daily tablet (Viking, February 2025). The most important fact: VK2735 is not an approved drug. As of October 2026 the injection is in two fully enrolled 78-week phase 3 trials (VANQUISH-1 and -2), and phase 3 trials of the tablet are registered but not yet recruiting. The best published human data are a 13-week phase 2 trial, VENTURE, in which weekly injections lowered body weight by 9.1–14.7% versus 1.7% on placebo (Bays et al., Obesity 2026).
This page summarizes what the published trial, Viking’s trial disclosures and the trial registries report. Much of the data beyond VENTURE comes from company press releases and conference posters that have not been peer-reviewed. It is for education only and is not medical advice.
| Property | Detail |
|---|---|
| Drug class | Dual GLP-1 and GIP receptor agonist (peptide with a half-life-extending side chain) |
| Developer | Viking Therapeutics (San Diego) |
| Routes studied | Subcutaneous injection once weekly; oral tablet once daily (same molecule) |
| Doses in trials | Injection: 2.5–15 mg/week (phase 2), 7.5, 12.5 and 17.5 mg/week (phase 3); tablet: 15–120 mg/day (phase 2), 27.5, 35 and 55 mg/day (planned phase 3) |
| Half-life | About 170–250 h after single injections (company-reported phase 1 data) |
| Best published result | −14.7% body weight at 13 weeks on 15 mg/week vs −1.7% on placebo (VENTURE, n = 176) |
| Approval status | Not approved anywhere; phase 3 for obesity |
| US controlled-substance status | Not listed in DEA Schedule III (21 CFR 1308.13) |
| WADA status | Not named on the 2026 List; as an unapproved drug it falls under S0 (non-approved substances), prohibited at all times |
What it is
VK2735 is a synthetic peptide built to combine the activity of both incretins, the gut hormones GLP-1 and GIP that the body releases after a meal. Viking describes it as binding the GLP-1 receptor (IC50 188 nM) and the GIP receptor (IC50 325 nM), citing its own unpublished data (Bays et al., Obesity 2026). IC50 is the concentration needed to block half of a reference ligand’s binding; lower means tighter binding. The peptide carries a side chain that extends its half-life after injection. Viking has not published the full structure in a peer-reviewed paper, so details of its design cannot be checked independently.
Activating the GLP-1 receptor lowers glucose, reduces appetite and body weight, and improves insulin sensitivity. Adding GIP receptor activity is thought to enhance these effects (Viking, September 2026).
How it compares with related drugs
| Drug | Receptors | Molecule | Route | Status |
|---|---|---|---|---|
| VK2735 | GLP-1 + GIP | Peptide | Weekly injection or daily tablet (same molecule) | Investigational, phase 3 |
| Tirzepatide | GLP-1 + GIP | Peptide | Weekly injection | FDA approved (Mounjaro, Zepbound) |
| Semaglutide | GLP-1 | Peptide | Weekly injection or daily tablet | FDA approved (Ozempic, Wegovy, Rybelsus) |
| Orforglipron | GLP-1 | Non-peptide small molecule | Daily tablet | See linked page |
Sources: Viking’s description of the approved comparators (Viking, September 2026); orforglipron trial (Wharton et al., NEJM 2025).
Viking’s stated rationale for the tablet is that patients could move between injection and tablet while staying on the same molecule, which it believes may reduce the risk of unexpected tolerability problems at the switch (Viking, February 2025). That is a design goal, not a tested outcome.
Pharmacokinetics
The only human kinetic figures are from Viking’s phase 1 single- and multiple-ascending-dose trial in healthy adults, reported in a March 2023 press release (Viking, March 2023):
| Parameter (single subcutaneous doses) | Value |
|---|---|
| Half-life | About 170–250 h (≈ 7–10 days) |
| Time to peak level (Tmax) | About 75–90 h |
A half-life of this length supports once-weekly injection. Viking has also tested every-other-week and monthly injections as maintenance regimens (see below). No full pharmacokinetic paper, and no oral bioavailability figure for the tablet, had been published as of October 2026.
Regulatory and development status
VK2735 is not approved by the FDA or any other regulator. The development path so far:
| Stage | Trial | Design | Status |
|---|---|---|---|
| Phase 1 | NCT05203237 | Single and multiple ascending doses, injection and 28-day tablet arms | Completed |
| Phase 2 | VENTURE (NCT06068946) | Weekly injection, 13 weeks, 176 adults | Completed; published 2026 |
| Phase 2 | VENTURE-Oral Dosing (NCT06828055) | Daily tablet, 13 weeks, 280 adults | Completed; topline and poster only |
| Phase 3 | VANQUISH-1 (NCT07104500) | Weekly injection, 78 weeks, adults without type 2 diabetes | Fully enrolled, about 4,500 |
| Phase 3 | VANQUISH-2 (NCT07104383) | Weekly injection, 78 weeks, adults with type 2 diabetes | Fully enrolled, about 1,000 |
| Phase 3 | SUNRISE 1 (NCT07868835) | Daily tablet, 68 weeks, without type 2 diabetes | Registered, not yet recruiting |
| Phase 3 | SUNRISE 2 (NCT07868939) | Daily tablet, 68 weeks, with type 2 diabetes | Registered, not yet recruiting |
Sources: ClinicalTrials.gov NCT05203237, NCT06068946, NCT06828055, NCT07104500, NCT07104383, NCT07868835, NCT07868939; enrollment from Viking, October 2026.
Both VANQUISH trials randomize participants to 7.5, 12.5 or 17.5 mg weekly or placebo, with percent change in body weight at week 78 as the primary endpoint. The VANQUISH registry entries list a primary completion date of July 2027. Viking completed an end-of-phase 2 meeting with the FDA in late 2024 before starting phase 3 (Viking, February 2025).
What the research shows
Weekly injection: phase 2 VENTURE trial
VENTURE was a randomized, double-blind, placebo-controlled, dose-ranging trial at 20 US sites, run from August 2023 to February 2024 (Bays et al., Obesity 2026; PMC full text). Key design points:
- Participants: 176 adults with a BMI of at least 30, or at least 27 plus a weight-related condition such as high blood pressure or sleep apnea. People with diabetes were excluded. Mean age was about 50; most were women.
- Treatment: 2.5, 5, 10 or 15 mg VK2735 or placebo, injected weekly for 13 weeks after a short dose step-up. All groups were advised to eat 500 kcal/day less and exercise about 150 minutes a week.
- Primary endpoint: percent change in body weight at week 13.
| Week 13 result | Placebo | 2.5 mg | 5 mg | 10 mg | 15 mg |
|---|---|---|---|---|---|
| Body weight change, % (95% CI) | −1.7 (−3.0 to −0.3) | −9.1 (−10.4 to −7.8) | −10.9 (−12.3 to −9.6) | −12.9 (−14.3 to −11.6) | −14.7 (−16.1 to −13.4) |
| Difference vs placebo, percentage points | — | −7.4 | −9.2 | −11.3 | −13.1 |
| Body weight change, kg | −1.8 | −9.2 | −10.7 | −13.3 | −14.6 |
| Lost ≥ 5% of weight | 11.5% | 80.8% | 97.0% | 93.8% | 100% |
| Lost ≥ 10% of weight | 3.0% | 40.1% | 65.1% | 70.4% | 89.1% |
| Lost ≥ 15% of weight | 0% | 12.8% | 11.6% | 31.2% | 41.5% |
All doses beat placebo (p under 0.0001 for the primary endpoint). Weight was still falling at week 13, with no plateau. In a subset of 75 people followed after the last dose, weight loss persisted at the 4- and 7-week follow-up visits.
Other findings over the 13 weeks:
- Blood sugar: among 74 people with prediabetes on VK2735, 58 (78%) had normal glucose values at week 13, and none progressed to diabetes. HbA1c fell by 0.27–0.36 percentage points on VK2735 versus a rise of 0.03 on placebo.
- Blood pressure: systolic pressure fell by 6.7–11.0 mmHg on VK2735 versus 4.2 mmHg on placebo.
- Lipids: most lipid markers drifted down, but only total cholesterol differed significantly from placebo in this short trial.
Daily tablet: phase 1
In the 28-day phase 1 study of the tablet in adults with a BMI of at least 30, once-daily doses ranged from 2.5 to 100 mg. Viking reported dose-dependent weight loss of up to 8.2% after 28 days, and up to 8.3% at day 57, four weeks after the last dose. All gastrointestinal side effects were reported as mild or moderate (Viking, February 2025). Groups in a phase 1 study are small, so these figures are only a first signal.
Daily tablet: phase 2 VENTURE-Oral Dosing
This 13-week randomized, double-blind, placebo-controlled trial enrolled 280 adults with obesity, or overweight plus a weight-related condition. Results have been released by press release and as a 2026 conference poster, not yet as a journal paper (Viking, August 2025; Hedges et al., ECO 2026 poster).
| Week 13 result | Placebo | 15 mg | 30 mg | 60 mg | 90 mg | 120 mg |
|---|---|---|---|---|---|---|
| Body weight change, % | −1.3 | −2.3 | −7.0 | −8.7 | −11.1 | −12.2 |
| Difference vs placebo, percentage points | — | −1.0 | −5.7 | −7.4 | −9.8 | −10.9 |
| Lost ≥ 10% of weight | 5% | 8% | 35% | 40% | 59% | 80% |
| Stopped treatment early | 18% | 20% | 20% | 28% | 25% | 38% |
The 15 mg dose did not separate from placebo; all doses from 30 mg upward did, from week 1 on. Higher doses were reached by stepping up every two weeks from 30 mg. A seventh, exploratory arm stepped up to 90 mg for four weeks and then dropped to 30 mg; that group had lost 8.1% of body weight at week 6 and 9.2% at week 13, after the dose reduction.
Maintenance with less frequent injections
Viking’s VK2735-102 maintenance study enrolled about 180 otherwise healthy adults with a BMI of at least 30 (Viking, September 2026). Everyone first received weekly VK2735 or placebo for 21 weeks, stepping up every two weeks to final doses of 15–22.5 mg. Topline results (press release only):
| Phase | Result |
|---|---|
| Induction, weeks 0–21 | Weight loss of 16.3–18.7% on VK2735 vs 0.1% on placebo |
| Maintenance, weeks 21–33, every-other-week injections (5–10 mg) | Kept 83–97% of the earlier weight loss (90% combined) |
| Maintenance, weeks 21–33, monthly injections (10–22.5 mg) | Kept 82–90% of the earlier weight loss (85% combined) |
| Maintenance, weeks 21–33, switched to placebo | Kept 61% of the earlier weight loss |
| Continued 17.5 mg weekly (exploratory, n = 13) | 21.7% total weight loss at week 33 |
Groups in the maintenance phase had only 10–16 people each, and the maintenance period was 12 weeks. A second part testing oral maintenance regimens started in October 2026, with results expected in 2027 (Viking, October 2026).
Comparison with tirzepatide, semaglutide and orforglipron
No trial has compared VK2735 head to head with any other drug, and its trials are much shorter than the phase 3 trials of approved drugs. The table below is context only; trial populations, durations and analysis methods differ.
| Drug and trial | Duration | Top-dose mean weight change | Placebo |
|---|---|---|---|
| VK2735 injection 15 mg/week, VENTURE (phase 2) | 13 weeks | −14.7% | −1.7% |
| VK2735 tablet 120 mg/day, VENTURE-Oral (phase 2) | 13 weeks | −12.2% | −1.3% |
| Semaglutide 2.4 mg/week, STEP 1 (phase 3) | 68 weeks | −14.9% | −2.4% |
| Tirzepatide 15 mg/week, SURMOUNT-1 (phase 3) | 72 weeks | −20.9% | −3.1% |
| Orforglipron 36 mg/day, ATTAIN-1 (phase 3) | 72 weeks | −11.2% | −2.1% |
Sources: Bays et al., Obesity 2026; Viking, August 2025; Wilding et al., NEJM 2021; Jastreboff et al., NEJM 2022; Wharton et al., NEJM 2025.
At a matched early time point, the VENTURE authors note that semaglutide produced about 6% and tirzepatide about 8% weight loss at week 12 in their phase 3 trials, compared with 9.1–14.7% for VK2735 at week 13 (Bays et al., Obesity 2026). Early speed of weight loss depends heavily on how fast the dose is stepped up, so this does not show that VK2735 will reach a larger final effect. The VANQUISH results will be the first long-term test.
Side effects and risks
Gastrointestinal effects
As with other GLP-1-based drugs, the main side effects are nausea, vomiting, constipation and diarrhea. In VENTURE, they were most common early in treatment and declined over time (Bays et al., Obesity 2026):
| VENTURE (injection), any severity | Placebo | 2.5 mg | 5 mg | 10 mg | 15 mg |
|---|---|---|---|---|---|
| Nausea | 20% | 26% | 46% | 37% | 63% |
| Constipation | 11% | 20% | 29% | 26% | 29% |
| Diarrhea | 9% | 31% | 17% | 20% | 11% |
| Vomiting | 0% | 9% | 17% | 17% | 29% |
| Adverse event leading to stopping treatment | 0% | 3% | 11% | 11% | 20% |
Nausea peaked in the first week in the 15 mg group, which started at 5 mg rather than 2.5 mg. The authors said the benefit of starting below 5 mg informed the phase 3 dose step-up design. Severe (grade 3) gastrointestinal events occurred in 0–9% of participants per arm, and none were life-threatening.
The tablet showed a similar pattern but higher dropout. In VENTURE-Oral, 20% of VK2735-treated participants stopped treatment because of an adverse event, compared with 13% on placebo; overall treatment discontinuation was 28% versus 18%. Nausea affected 58% versus 48% and vomiting 26% versus 10% (Viking, August 2025). Nausea on placebo (48%) was much more common than in the injection trial (20%), which makes the drug-placebo gap look smaller.
Heart rate
Resting heart rate rose on VK2735 in VENTURE: mean increases of 3.3–9.3 beats per minute versus 1.4 on placebo (Bays et al., Obesity 2026). Its long-term meaning is not yet known.
Serious adverse events
In VENTURE, 8 of 175 treated participants (4.6%) had 12 serious adverse events. Investigators judged two of them related to the drug, in one person on 5 mg: atrial fibrillation (possibly related) and dehydration (probably related). One participant on 15 mg died of head trauma from a fall, judged unrelated to the drug (Bays et al., Obesity 2026). Other events of interest:
- Pancreatitis: none reported.
- Gallbladder events: cholecystitis or gallstones in 2 people on VK2735. In phase 1, one person with a history of gallstones had a serious gallstone obstruction (Viking, March 2023).
- Anti-drug antibodies: detected at week 13 in 9–23% of VK2735-treated participants. Their effect on efficacy or safety was not reported.
In VENTURE-Oral, three participants had drug-related serious events: angioedema and hives in one person on 60 mg, and dehydration or nausea and vomiting in people on 120 mg (Hedges et al., ECO 2026 poster).
What is not yet known
Each VK2735 trial reported so far lasted 13–33 weeks and enrolled at most a few hundred people. There are no data on:
- long-term safety, including rare adverse events that small, short trials cannot detect;
- cardiovascular outcomes;
- loss of lean mass versus fat mass;
- use in pregnancy, in children or in older adults with frailty.
VENTURE excluded people with diabetes; VANQUISH-2 and SUNRISE 2 are the first trials designed for type 2 diabetes.
Products sold outside clinical trials
Viking describes itself as a clinical-stage company (Viking, October 2026) and has no marketed product; the drug is available legally only inside clinical trials. The FDA has warned online sellers of similar incretin peptides (semaglutide, tirzepatide, retatrutide and others) that “research use only” labels do not stop such products from being unapproved new drugs (FDA warning letter, December 2024). Products sold online under the VK2735 name have not been reviewed by any regulator, and their identity, purity and dose cannot be verified.
Legal status and use in sport
In the US, VK2735 is an investigational drug. It is not a controlled substance and is not listed among the Schedule III anabolic steroids (21 CFR 1308.13).
VK2735 is not named on the WADA Prohibited List. However, the S0 class bans “any pharmacological substance” not covered elsewhere on the List that has no current approval by any government health authority, explicitly including drugs “under pre-clinical or clinical development” (WADA 2026 Prohibited List). As an unapproved investigational drug, VK2735 falls into that class and is prohibited at all times. This could change if a regulator approves it.
Key takeaways
- A dual GLP-1/GIP agonist like tirzepatide. VK2735 is a peptide with a half-life of roughly 7–10 days, developed as both a weekly injection and a daily tablet of the same molecule.
- Strong but short phase 2 results. Weekly injections cut body weight by 9.1–14.7% in 13 weeks versus 1.7% on placebo in the published VENTURE trial, with no plateau yet.
- The tablet works but is harder to tolerate. Daily tablets produced up to 12.2% weight loss in 13 weeks, but 28% of treated participants stopped early (18% on placebo); these results are not yet peer-reviewed.
- Typical incretin side effects. Nausea, vomiting and constipation dominated, were dose-related and eased after the first weeks; heart rate rose by up to about 9 beats per minute.
- No head-to-head or long-term data. Comparisons with tirzepatide, semaglutide and orforglipron are across trials of very different lengths; the 78-week VANQUISH trials will be the first real test.
- Not approved, and banned in sport. VK2735 is investigational everywhere and falls under WADA’s S0 non-approved substances class.
Sources
- Bays HE, Toth P, Alkhouri N, et al. Weekly Subcutaneous VK2735, a GIP/GLP-1 Receptor Dual Agonist, for Weight Management: Phase 2, Randomized, 13-Week VENTURE Study. Obesity (Silver Spring). 2026;34(3):537–549. PubMed; PMC.
- Viking Therapeutics. Viking Therapeutics Announces Results from Phase 1 Clinical Trial of Dual GLP-1/GIP Receptor Agonist VK2735. Press release (SEC Form 8-K exhibit 99.1), March 28, 2023. SEC.
- Viking Therapeutics. Viking Therapeutics Reports Fourth Quarter and Year-End 2024 Financial Results and Provides Corporate Update. Press release, February 5, 2025. Viking.
- Viking Therapeutics. Viking Therapeutics Announces Positive Top-Line Results from Phase 2 VENTURE-Oral Dosing Trial of VK2735 Tablet Formulation in Patients with Obesity. Press release, August 19, 2025. Viking.
- Hedges PJ, Bays H, Freilich B, et al. Treatment with Oral VK2735 Results in Significant Weight Loss: The Randomized, Placebo-Controlled, Dose-Finding, VENTURE-Oral Study. Poster, European Congress on Obesity, Istanbul, May 12–15, 2026. Viking.
- Viking Therapeutics. Viking Therapeutics Announces Positive Topline Results from Maintenance Study of GLP-1/GIP Agonist VK2735 Demonstrating the Promise of Multiple Maintenance Dosing Regimens. Press release, September 22, 2026. Viking.
- Viking Therapeutics. Viking Therapeutics Announces Initiation of VK2735 Oral Maintenance Dosing Clinical Trial in Patients with Obesity. Press release, October 6, 2026. Viking.
- Viking Therapeutics. Phase 1 Study to Evaluate the Safety and Tolerability of VK2735. NCT05203237. ClinicalTrials.gov.
- Viking Therapeutics. VK2735 for Weight Management Phase 2 (VENTURE). NCT06068946. ClinicalTrials.gov.
- Viking Therapeutics. VK2735 for Weight Management Phase 2 (Venture Oral Dosing). NCT06828055. ClinicalTrials.gov.
- Viking Therapeutics. VK2735 for Weight Management Phase 3 (VANQUISH-1). NCT07104500. ClinicalTrials.gov.
- Viking Therapeutics. VK2735 for Weight Management Type 2 Diabetes Phase 3 (VANQUISH 2). NCT07104383. ClinicalTrials.gov.
- Viking Therapeutics. Oral VK2735 for Weight Management Phase 3 (SUNRISE 1). NCT07868835. ClinicalTrials.gov.
- Viking Therapeutics. Oral VK2735 for Weight Management in Adults With Type 2 Diabetes Mellitus Phase 3 (SUNRISE 2). NCT07868939. ClinicalTrials.gov.
- 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. PubMed.
- 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. PubMed.
- Wharton S, Aronne LJ, Stefanski A, et al. Orforglipron, an Oral Small-Molecule GLP-1 Receptor Agonist for Obesity Treatment. N Engl J Med. 2025;393(18):1796–1806. PubMed.
- US Food and Drug Administration. Warning letter to Summit Research Peptides, MARCS-CMS 695607, December 10, 2024. FDA.
- Code of Federal Regulations. 21 CFR 1308.13, Schedule III. eCFR.
- World Anti-Doping Agency. World Anti-Doping Code International Standard: Prohibited List 2026. WADA 2026 Prohibited List.