2026-08-21 · By WeightFAQ Staff

VK2735 for Weight Loss: What Viking Therapeutics’ Dual GLP-1/GIP Pipeline Actually Looks Like in 2026

VK2735 is not FDA-approved and is not sold anywhere in the United States as of August 2026 — no legitimate pharmacy, telehealth clinic, or compounding operation can supply it. It is an investigational drug from Viking Therapeutics (San Diego, California), a peptide dual GLP-1 and GIP receptor agonist developed in parallel as a once-weekly subcutaneous injection (VK2735 SC) and a once-daily oral tablet (VK2735 oral). VK2735 activates the same two receptors as tirzepatide (Zepbound) but is being developed in both formulations at once — the only next-generation obesity candidate with that parallel-formulation strategy.

The headline data: the VENTURE-1 Phase 2 SC trial (Viking Therapeutics topline, March 2024) reported roughly 14.7 percent placebo-adjusted weight loss at 13 weeks at the 5 mg dose — the largest short-timeframe weight-loss signal ever reported for a Phase 2 obesity trial. For context, semaglutide reached roughly 6 percent and tirzepatide roughly 8 percent in equivalent 12-week windows. The 13-week timeframe is short, so what the 52-week Phase 3 magnitude will be is genuinely unknown.

This page explains what VK2735 is, what the VENTURE-1 data actually showed, how the parallel oral tablet program is progressing, how it compares to the rest of the next generation weight loss drugs pipeline, and the honest 2026 read for US patients — including the uncertainty surrounding approval and the risks of unverified products.

What VK2735 is

VK2735 is a peptide dual receptor agonist. It engineers two mechanisms into one chemical entity:

• GLP-1 receptor activation — the same receptor that Ozempic, Wegovy, Mounjaro, Zepbound, Rybelsus, and orforglipron activate. GLP-1 signalling drives satiety through the hypothalamic arcuate and paraventricular nuclei, delays gastric emptying, and improves insulin secretion.
• GIP receptor activation — the second incretin receptor that tirzepatide engages. Adding GIP agonism on top of GLP-1 is the mechanistic reason tirzepatide reaches roughly 21 percent weight loss versus roughly 15 percent for semaglutide.

The investigational peptide is being studied in both injectable and oral formulations. Orforglipron is a small-molecule oral drug that targets GLP-1 alone. The formulations have not been established as interchangeable.

Plain-English mechanism: VK2735 activates the same two receptors as tirzepatide (Zepbound) but is being developed in both an injectable and an oral form, aiming to give patients a choice between a weekly shot and a daily pill.

Dose and route — how VK2735 sits alongside tirzepatide and Rybelsus

VK2735 is being studied in two formulations. These differ from the approved injectable tirzepatide and oral semaglutide products below; investigational formulations are not guaranteed to reach pharmacies.

• VK2735 injection: investigational, once weekly. Administration details are not established for an approved product.
• VK2735 oral: investigational, once daily in the registered studies. Doses were studied in Phase 2; Phase 3 is planned. Approved-product dosing instructions are not established.
• Tirzepatide (Zepbound): once-weekly subcutaneous injection.
• Rybelsus (oral semaglutide): daily tablet with specific fasting and water instructions; follow the current prescription label.

Rybelsus has specific administration instructions. Do not assume those instructions apply to investigational oral VK2735; its eventual dosing instructions, if approved, are not established.

VENTURE-1 Phase 2 SC obesity trial — the headline data

VK2735 SC is the more mature of the two formulations. The pivotal Phase 2 signal came from the VENTURE-1 trial, whose topline Viking Therapeutics reported in March 2024.

• Design: randomized, double-blind, placebo-controlled, dose-titration.
• Population: 176 adults with BMI ≥ 30, or ≥ 27 with at least one weight-related comorbidity.
• Duration: 13 weeks.
• Doses: 2.5 mg, 5 mg, 7.5 mg, 10 mg once-weekly subcutaneous.
• Primary endpoint: mean percent weight change from baseline to week 13.

The topline number that reset expectations: roughly −14.7 percent placebo-adjusted weight loss at the 5 mg dose at 13 weeks, with a clear dose-response from 2.5 mg → 5 mg. For context, both semaglutide and tirzepatide were used as comparator benchmarks in the same short-window territory:

The 14.7 percent at 13 weeks signal is the largest short-timeframe magnitude reported for any Phase 2 obesity trial to date. The important honest qualifier is that 13 weeks is short — the weight-loss curve had not plateaued, so the eventual 52-week Phase 3 number is genuinely unknown. It could land above tirzepatide’s 21 percent SURMOUNT-1 number, at it, or below it. That question is exactly what Phase 3 is designed to answer.

Oral VK2735 development

ClinicalTrials.gov describes NCT06828055 as a 13-week Phase 2 oral dose-finding trial in adults. The registry lists it as completed on August 15, 2025; the registry entry does not itself report results.

The SUNRISE 1 registry record describes a planned 68-week Phase 3 oral study in adults without type 2 diabetes. Its October 16, 2026 update lists it as not yet recruiting, with a November 2026 estimated start and July 2028 estimated primary completion. Estimated dates can change; a registry listing is not an approval or proof of effectiveness. Both records describe VK2735 as a peptide dual GLP-1/GIP agonist.

Mechanism — why dual GLP-1/GIP matters

Adding GIP receptor agonism on top of GLP-1 is the mechanistic story behind tirzepatide’s roughly 21 percent SURMOUNT-1 magnitude versus semaglutide’s roughly 15 percent STEP-1 magnitude. Frías JP et al. (NEJM 2018) is the foundational tirzepatide Phase 2 mechanism paper (SURPASS pre-Phase 3 dose-ranging), and Jastreboff AM et al. (NEJM 2022, SURMOUNT-1) is the Phase 3 obesity trial that established the dual-agonist superiority over placebo and, in cross-trial comparison, over semaglutide.

The mechanism is complementary rather than redundant. GLP-1 receptor activation drives satiety through hypothalamic circuits and delays gastric emptying. GIP receptor activation adds effects on adipose tissue lipid handling, food intake regulation via a different neural circuit, and — pharmacologically — attenuates some of the nausea burden that comes with high-dose GLP-1 monotherapy. The net effect at matched exposure is more weight loss with tolerability comparable to the single-receptor drug.

An investigational peptide dual GLP-1/GIP agonist being studied in oral form is a commercially and clinically meaningful step. Commercially, the injectable multi-receptor market is dominated by two Lilly and Novo peptides today; a Viking-controlled alternative changes the competitive landscape. If approved, an oral dual agonist could offer another option for patients who cannot or prefer not to inject. For the full family view of the on-label class today, see the GLP-1 medications comparison.

Pipeline comparison — VK2735 and other treatments

These treatments differ in route, development stage and receptor targets. Cross-trial comparisons cannot establish relative effectiveness.

• VK2735 injection: Viking Therapeutics’ investigational peptide GLP-1/GIP agonist. A Phase 2 injection trial has been reported; approval is uncertain.
• VK2735 oral: the same investigational peptide class in a daily tablet. Phase 2 was completed; SUNRISE 1 Phase 3 was not yet recruiting in its October 2026 registry update. Approval is uncertain.
• Orforglipron: an oral small-molecule GLP-1 agonist developed by Eli Lilly.
• Tirzepatide (Zepbound): a weekly injectable peptide GLP-1/GIP agonist approved for specified indications.
• Retatrutide: an investigational weekly GLP-1/GIP/glucagon agonist from Eli Lilly.
• Semaglutide (Wegovy): a weekly injectable GLP-1 agonist approved for specified indications.

VK2735 remains investigational in both formulations; cross-trial comparisons cannot establish which drug is more effective.

Safety profile from Phase 2

The VENTURE-1 safety picture is a class-typical incretin tolerability profile at short exposure. The important caveats are the small sample size (n=176) and short window (13 weeks) — the class-defining long-term safety questions are all Phase 3 questions.

• Nausea — roughly 15 to 25 percent at the 5 mg dose, higher at 7.5 and 10 mg. Consistent with the GLP-1 class and comparable to early tirzepatide titration.
• Vomiting and diarrhea — single-digit to low-double-digit percent, titration-related, mostly during weeks 1 to 4.
• Transient LFT bump — a single-digit-percent subset of patients had a transient rise in liver-function tests during titration, reported in Viking’s Phase 2 briefing. The pattern was consistent with early-course GI-adaptive changes rather than hepatotoxicity, and resolved with continued dosing in most patients.
• Cardiac signal — no cardiac signal detected at 13 weeks. Heart rate was neutral (VK2735 does not activate the glucagon receptor, unlike survodutide or retatrutide, so a glucagon-arm heart-rate signal is not expected).
• Off-target signal — none reported in Phase 2 topline.

The class-defining safety questions require Phase 3 exposure to answer. Those questions are:

• Thyroid C-cell hyperplasia and medullary thyroid carcinoma (MTC) — the incretin class carries a boxed warning for this in rodent studies. The clinical human signal remains uncertain but any next-generation drug in this class will carry the MTC / MEN2 warning language.
• Pancreatitis — a class safety topic. Signal in Phase 3 is what matters.
• Gastroparesis and delayed gastric emptying — the class delays gastric emptying by design; the clinical severity spectrum is Phase 3 characterization.
• Long-term LFT trend — the Phase 2 transient bump should be tracked over 52 weeks or more of Phase 3 exposure.

Phase 3 timeline expectations

Viking Therapeutics has publicly guided VK2735 SC into a Phase 3 obesity program with enrolment starting late 2025 into 2026. The realistic reasoning on the timeline:

• Phase 3 SC enrolment — late 2025 / 2026.
• Phase 3 SC primary readout — 2027 to 2028 depending on trial length (52 weeks is the standard obesity endpoint; a longer cardiovascular outcomes study would push later).
• FDA submission — 2028 to 2029 for the SC form, assuming positive primary readout.
• FDA review — 10 to 18 months. Priority review would compress; standard review would land in 2029 to 2030.
• Earliest realistic SC availability on US pharmacy shelves — 2028 to 2029.
• Oral form — the Phase 2 study is complete and SUNRISE 1 was not yet recruiting in its October 2026 registry update. Future milestones and approval are uncertain.

For comparison against the drugs closest to VK2735 in the pipeline:

• Orforglipron — Phase 3 ATTAIN-1 already reported; Lilly guidance is regulatory submission by mid-2026 window; realistic first-to-market oral GLP-1 in 2026 to 2027.
• Retatrutide — Phase 3 TRIUMPH enrolment complete for some arms; obesity readouts 2026 to 2027; earliest availability 2027 to 2028.
• Tirzepatide — already approved (Zepbound 2023 for obesity, Mounjaro 2022 for T2D); available today.

VK2735 SC lands in the 2028 to 2029 window at the earliest — behind orforglipron, retatrutide, CagriSema, and probably MariTide.

The commercial and licensing angle

Unlike Eli Lilly and Novo Nordisk, Viking Therapeutics is a small-cap NASDAQ biotech (approximate market capitalization in the roughly 5 to 15 billion dollar range as of 2026) without an in-house commercial infrastructure. That matters for patients because it means the path from Phase 3 success to a bottle on a US pharmacy shelf will go through one of two commercial routes:

• Big Pharma acquisition. Lilly, Novo Nordisk, Pfizer, Merck, and other large-pharma acquirers have been publicly discussed as prospective buyers of Viking or of the VK2735 program specifically. An acquisition typically triggers integration of the acquired asset into the acquirer’s commercial engine (manufacturing scale-up, contracted formulary access, PBM negotiation).
• Commercialization partnership. A licensing or co-development deal in which Viking retains partial economics while a larger partner runs Phase 3 completion, submission, and launch.

Which route Viking takes will be decided by 2027 Phase 3 readout timing and by any Big Pharma deal that follows. Whether VK2735 reaches patients as a Viking-branded product, a Lilly-branded product, or a co-marketed product will be decided by 2027 Phase 3 outcomes and any acquisition deal that follows — and that determines pricing, formulary placement, and prior-authorization pathways in 2028 to 2029.

For the current 2026 pricing landscape and Medicare Part D coverage picture that VK2735 will inherit, see GLP-1 cost and insurance.

What VK2735 does not do in 2026

The Phase 2 headline number is genuinely exciting, but the honest limits matter for any 2026 reader making a treatment decision.

• Not FDA-approved for any indication. No US access route exists.
• Avoid unverified products. VK2735 is investigational. Do not take products marketed as VK2735 outside a legitimate clinical trial; consult a licensed clinician about medication safety.
• No head-to-head data against tirzepatide, orforglipron, retatrutide, or any next-generation pipeline drug. Every side-by-side comparison in this article and elsewhere is cross-trial.
• No cardiovascular outcomes trial (CVOT) yet. Viking has not initiated a dedicated CVOT for VK2735; a Phase 3 obesity program with a cardiovascular sub-study or a separate CVOT would be needed before any cardiovascular-risk-reduction indication analogous to Wegovy’s SELECT.
• No T2D indication yet. Viking’s diabetes program is a separate molecule; VK2735 has not filed for or been developed against a T2D primary endpoint.

Practical read for US patients in 2026

If you are considering weight-management medication, talk with a qualified clinician about approved options, benefits, risks, coverage and your circumstances. VK2735 remains investigational; neither its approval nor its timing is guaranteed. Do not switch or stop medication without clinical guidance.

For current study status, consult the Phase 2 oral study and SUNRISE 1 registry entries.

For the full 2026 map of pipeline drugs, mechanism trees, and the practical “should I wait?” protocol, see the next generation weight loss drugs pillar. For the on-label 2026 options that are actually on pharmacy shelves today, see prescription weight loss medications, semaglutide for weight loss, and tirzepatide for weight loss.

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