VK2735 (Viking Therapeutics): GIP/GLP-1 Dual Agonist Weight-Loss Evidence

VK2735 is an investigational obesity drug from Viking Therapeutics that activates the same two receptors as tirzepatide — the GLP-1 receptor and the GIP (glucose-dependent insulinotropic polypeptide) receptor. What sets the program apart is that Viking is developing VK2735 in two formulations at once: a once-weekly subcutaneous injection and an oral tablet. The injectable version produced double-digit weight loss in just 13 weeks in the phase 2 VENTURE trial, which is why the molecule attracts heavy investor and biohacker attention. But VK2735 is not FDA-approved, is not legally for sale, and is still years from any approval decision. This article covers what VK2735 is, what the VENTURE data actually showed, how the oral and subcutaneous programs differ, how the magnitude compares to approved drugs, and where it sits in the development timeline.

The honest summary

• VK2735 is a GIP/GLP-1 dual agonist — the same receptor pair as tirzepatide. It activates both the GLP-1 receptor (appetite suppression, slowed gastric emptying, glucose-dependent insulin release) and the GIP receptor. This is the same mechanistic class as tirzepatide (Zepbound/Mounjaro), not the GLP-1/glucagon class of mazdutide or survodutide.
• It is investigational, not FDA-approved. As of 2026, VK2735 has completed phase 2 and is not approved by the FDA or any other regulator. It is not legally marketed, prescribed, or compounded. Anything sold as "VK2735" through research-peptide channels is outside any approved supply chain.
• VENTURE is the pivotal phase 2 evidence. The phase 2, randomized, double-blind, placebo-controlled VENTURE study (Bays 2026, Obesity^[1]) tested weekly subcutaneous VK2735 over just 13 weeks in adults with obesity or overweight plus a weight-related comorbidity. The top dose (15 mg) produced a mean −14.7% body-weight reduction versus −1.7% on placebo.
• Two formulations are in development. Viking is advancing both a once-weekly subcutaneous injection and an oral tablet of VK2735. The subcutaneous version has the most mature published data (VENTURE); the oral program is earlier-stage.
• Magnitude is promising but the trial was short. VENTURE's −14.7% came in only 13 weeks, whereas the approved-drug benchmarks — semaglutide STEP-1 (−14.9% at 68 weeks^[2]) and tirzepatide SURMOUNT-1 (−20.9% at 72 weeks^[3]) — come from year-plus trials. A short-trial number cannot be directly stacked against a long-trial number.

What VK2735 actually is, pharmacologically

VK2735 is a peptide engineered to activate two incretin receptors simultaneously: the GLP-1 receptor and the GIP receptor. That pairing is the defining feature of tirzepatide, the most effective obesity drug currently approved in the US. The GLP-1 arm suppresses appetite, slows gastric emptying, and triggers glucose-dependent insulin release; the GIP arm is thought to add complementary effects on insulin sensitivity and appetite regulation. Putting both in one molecule is the engineering bet that VENTURE was designed to test in humans.

It is worth being precise about the receptor combination, because the emerging-pipeline conversation lumps very different molecules together. VK2735 is a GIP/GLP-1 dual agonist — the tirzepatide class. That is mechanistically distinct from the GLP-1/glucagon dual agonists (mazdutide, survodutide, pemvidutide) and from the triple agonist retatrutide (GLP-1/GIP/glucagon). When people describe VK2735 as "a tirzepatide-class drug," that is accurate at the receptor level; whether it ultimately matches tirzepatide's efficacy and tolerability is a separate, still-open question.

The pivotal phase 2 trial: VENTURE (subcutaneous)

VENTURE (Bays 2026, Obesity^[1]; ClinicalTrials.gov NCT06068946) is the most mature published evidence for VK2735. It was a phase 2, randomized, double-blind, placebo-controlled, dose-ranging study of weekly subcutaneous VK2735 in adults with obesity or overweight plus at least one weight-related comorbidity. Adults with diabetes were excluded. The primary endpoint was percent change in body weight at week 13 — a deliberately short readout for a dose-finding study. The trial ran between August 2023 and February 2024.

Across the active-treatment doses, mean weight reduction ranged from 9.2 kg (−9.1%) on the lowest 2.5 mg dose to 14.6 kg (−14.7%) on the highest 15 mg dose, versus a 1.8 kg (−1.7%) reduction on placebo. Among everyone on active treatment, 93% (130 of 140) achieved at least a 5% weight reduction, compared with 12% (4 of 34) on placebo. As with every incretin drug, the most common adverse events were gastrointestinal — the abstract notes their reported frequency decreased after dose titration reached steady state.

Oral vs subcutaneous: two programs, different maturity

One of the most-discussed features of the VK2735 program is the oral tablet. An effective oral GIP/GLP-1 agonist would matter because most of the highly effective obesity drugs are injectables; an oral option could widen access and appeal to needle-averse patients. Viking has advanced an oral VK2735 program through early clinical testing, but the published, peer-reviewed weight-loss evidence summarized in this article — the VENTURE trial^[1] — is for the subcutaneous formulation. The oral program is at an earlier stage, and its longer-term efficacy and tolerability in larger trials remain to be established.

The practical implication is that "VK2735" is really two candidates traveling together. The subcutaneous version carries the headline VENTURE data; the oral version carries the bigger strategic upside but a thinner published evidence base so far. When you see VK2735 weight-loss numbers quoted, it is worth checking which formulation they describe.

Magnitude: VK2735 vs the approved drugs

The chart is easy to misread, so the caveat matters more than usual here. VK2735's −14.7% looks close to semaglutide's STEP-1 result, but VENTURE ran 13 weeks and STEP-1 ran 68 weeks. A drug that reaches nearly 15% in a quarter of the time is, if anything, an encouraging trajectory — but the honest reading is that we do not yet have a long-duration VK2735 trial to compare like-for-like against the approved drugs. Whether VK2735 ultimately lands near semaglutide, near tirzepatide, or somewhere else is exactly what its phase 3 program would need to answer.

Where VK2735 sits in the development timeline

As of 2026, VK2735 has completed phase 2 (VENTURE) for the subcutaneous formulation and is generating intense investor interest precisely because the early efficacy looks competitive with the approved tirzepatide class. But "phase 2 looks good" is a long way from "available at the pharmacy." A successful obesity drug typically needs a multi-thousand-patient, year-plus phase 3 program demonstrating durable weight loss and safety, followed by FDA review. None of that had produced an approval for VK2735 as of 2026, and the realistic timeline to any approval is measured in years, not months.

The practical takeaway for someone in the US researching VK2735 is that it is not a prescribable option today. The relevant approved drugs remain semaglutide (Wegovy/Ozempic, STEP-1^[2]) and tirzepatide (Zepbound/Mounjaro, SURMOUNT-1^[3]) — the latter sharing VK2735's exact GIP/GLP-1 mechanism and already FDA-approved with year-plus efficacy data. Anything marketed as "VK2735" through US research-peptide or gray-market channels is operating entirely outside the regulated supply chain and carries the identity, purity, and dosing risks inherent to unapproved peptides. The honest answer to "can I get VK2735?" in 2026 is: not legitimately. Talk to a clinician about the approved drugs instead.

Related research

• GLP-1 pipeline overview — the broader landscape of non-Lilly, non-Novo pipeline drugs, for context on where VK2735 fits among the emerging molecules
• Mazdutide GLP-1/glucagon evidence — a different dual-agonist class (glucagon rather than GIP), useful for understanding how VK2735's tirzepatide-style mechanism differs
• Tirzepatide vs semaglutide head-to-head — the approved GIP/GLP-1 drug (tirzepatide) shares VK2735's exact receptor combination, making it the closest reference point
• Retatrutide triple-agonist evidence — Lilly's GLP-1/GIP/glucagon agonist, which adds a third receptor on top of VK2735's two
• Zepbound (tirzepatide) — the FDA-approved GIP/GLP-1 dual agonist and the current best-in-class obesity drug
• Wegovy (semaglutide 2.4 mg) — the STEP-1 reference standard for new obesity drugs

Important disclaimer. VK2735 is investigational and not FDA-approved in the United States as of 2026. The data summarized here come from the phase 2 VENTURE trial of the subcutaneous formulation; cross-trial comparisons to semaglutide and tirzepatide are directional, not head-to-head, and VENTURE's 13-week duration is far shorter than the approved-drug trials. This article is educational and does not constitute medical advice or an endorsement to use any unapproved product marketed as "VK2735." All PMIDs were verified live against the PubMed E-utilities API on 2026-06-01.

Last verified: 2026-06-01. Next review: every 6 months, or sooner if VK2735 enters or completes phase 3, if Viking Therapeutics publishes oral-formulation efficacy data, or if the FDA accepts a VK2735 application for review.