VK2735 (Viking)

VK2735 is an experimental obesity drug from a company called Viking Therapeutics. It’s part of the incretin family (a group of gut-hormone-based drugs that turn down appetite) — the same broad family as semaglutide and tirzepatide. It has drawn a lot of buzz for two reasons: its early results in people look strong, and Viking is building both an injectable version and a pill. But “early results in people” is exactly the stage this drug is at. No regulator has approved it, you can’t get it as a prescription, and we don’t yet know whether it’s safe to use for years. Anything sold outside of a clinical trial as “VK2735” is unapproved, and nobody has confirmed what’s actually in it.

What it is

VK2735 is a dual agonist of the GLP-1 and GIP receptors — meaning it switches on two gut-hormone receptors at once (agonist = a molecule that activates a receptor). Turning on both of these receptors curbs appetite, slows how fast your stomach empties, and improves blood-sugar and metabolic control. Together, that adds up to weight loss. In how it works, it’s in the same class as tirzepatide.

Viking is developing it in two forms: a once-a-week shot under the skin (subcutaneous, meaning injected into the fat layer just beneath the skin) and a once-a-day pill. It’s being studied for obesity, being overweight, and metabolic disease.

One thing worth saying clearly: VK2735 is not a muscle-building or “anabolic” drug. It has nothing to do with myostatin or growth factors (the biological pathways that actually build muscle). Any marketing that pitches it as a muscle compound is making up a claim the science simply doesn’t back.

The claims

You’ll see VK2735 hyped as a next-generation, “tirzepatide-but-better” weight-loss drug, sometimes with the pill version sold as a way to skip the needles. Some sellers go even further — quoting exact side-effect numbers for each dose, or claiming it’s been added to a list of banned substances for athletes. Here’s what the actual evidence supports, and where those claims get ahead of it.

What the evidence actually shows

Subcutaneous VENTURE (Phase 2) — peer-reviewed and published. This is the strongest evidence in humans so far. It was a randomized, double-blind, placebo-controlled trial (randomized = people were sorted into groups by chance; double-blind = neither patients nor doctors knew who got the drug; placebo-controlled = compared against a dummy treatment), and it ran for 13 weeks testing a range of doses (NCT06068946). It enrolled 176 participants (174 in the main analysis) across 2.5 / 5.0 / 10 / 15 mg groups plus a placebo group. The main goal — percent change in body weight at Week 13 — was met. At the 15 mg dose, average weight change was −14.7% (95% CI −16.11, −13.38) compared with −1.7% for placebo, and weight was still dropping (no plateau) by week 13. The results were published in the journal Obesity (Silver Spring) in 2026.

Oral VENTURE-Oral (Phase 2) — company-reported and conference data, not yet a peer-reviewed paper. This 13-week trial enrolled 280 adults across six once-a-day dose groups (15 / 30 / 60 / 90 / 120 mg) plus placebo (about 40 people each). Early (“top-line”) results were announced in August 2025 and presented at the ECO 2026 conference in May 2026. Reported average weight loss reached as much as −12.2% at the highest dose versus −1.3% on placebo, with up to 97% of participants losing at least 5% of their body weight and up to 80% losing at least 10%. Because these are company and conference figures that haven’t yet been published in a peer-reviewed journal, treat the dose-by-dose numbers as preliminary.

Phase 3 is running but hasn’t reported results yet. The VANQUISH program started June 25, 2025. VANQUISH-1 (obesity, about 4,650 adults) finished enrolling November 19, 2025; VANQUISH-2 (type 2 diabetes with obesity or overweight, about 1,000 adults, weekly shot) finished enrolling March 26, 2026. Both run 78 weeks of dosing (7.5 / 12.5 / 17.5 mg vs placebo). No Phase 3 efficacy result has been reported as of June 2026. There are no head-to-head trials pitting it directly against tirzepatide or semaglutide, and no long-term outcome data.

Legal and regulatory status

VK2735 is investigational only and not approved anywhere. You can’t get it as a prescription drug.

On anti-doping: GLP-1 / GIP receptor agonists are not banned by WADA (the World Anti-Doping Agency). In WADA’s 2026 update, markers of semaglutide and tirzepatide are on the 2026 Monitoring Program (both in and out of competition). Being monitored just means WADA is watching for patterns of misuse — it is not itself a doping violation. As an unlisted investigational drug in the same class, VK2735 is not on the Prohibited List. That said, monitoring-program status can change from year to year, so athletes should treat these substances with caution.

There’s a claim going around from sellers that GLP-1 drugs were moved to “full S4 prohibition” in 2026. That’s false: the official WADA/NADO summary puts them on the Monitoring Program, not the Prohibited List.

For contrast, this is different from growth factors like MGF and IGF-1 (and their close relatives), which are banned under WADA Section S2 (peptide hormones, growth factors, and related substances — prohibited at all times). VK2735 does not fall in that category.

Safety

The side effects are mostly digestive, which is expected for this class of drug.

In the published subcutaneous VENTURE trial, the most common side effects were nausea (36.6%, 64/175), constipation (21.1%, 37/175), and vomiting (12.6%, 22/175). Serious side effects linked to treatment happened in 4.6% (8/175) of people, and 9.1% (16/175) stopped the drug because of a side effect.

For the oral Phase 2 trial, the company reported that roughly 98–99% of (digestive/drug-related) side effects were mild or moderate, with digestive issues showing up more often at higher doses. Tolerating the higher doses is a genuine concern. One note: some dose-by-dose dropout figures were passed around for the oral trial (for example, “~13% placebo vs ~38% at 120 mg”), but those could not be confirmed against a primary source — the verified press releases don’t break dropouts out by dose — so don’t treat those exact numbers as fact.

Most important of all: we don’t yet know whether it’s safe long-term. The 78-week Phase 3 results, plus any heart-health or long-term safety data, haven’t come out yet. And because there’s no approved label, there’s no proper safety-monitoring system in place for anyone using it outside a trial.

Bottom line

Of the current crop of next-generation incretin drugs, VK2735 has the most encouraging early human data, anchored by a peer-reviewed Phase 2 trial of the injectable form showing roughly 15% weight loss at 13 weeks. But it’s still experimental: the Phase 3 trials are fully enrolled but haven’t reported, the pill data are still only company-reported, and long-term safety is genuinely unknown. It’s not approved, it’s not a prescription drug, and it’s not a muscle-building compound. Think of it as a promising candidate still working its way through trials — not a proven treatment, and not something with a known safety record for use outside a trial.

Evidence grade: 7/10 · Moderate.

Sources

• Bays HE et al., “Weekly Subcutaneous VK2735… Phase 2, 13-Week VENTURE Study,” Obesity (Silver Spring) 2026;34(3):537–549 (PubMed)
• VENTURE Phase 2 full text (PMC)
• Viking Therapeutics: Publication of Phase 2 VENTURE results in Obesity (Jan 12, 2026)
• Viking Therapeutics: Positive top-line results from Phase 2 VENTURE-Oral (Aug 19, 2025)
• Viking Therapeutics: Phase 2 VENTURE-Oral data at ECO 2026 (May 12, 2026)
• Viking Therapeutics: Initiation of Phase 3 VANQUISH program (Jun 25, 2025)
• Viking Therapeutics: Completion of enrollment in Phase 3 VANQUISH-1 (Nov 19, 2025)
• Viking Therapeutics: Completion of enrollment in Phase 3 VANQUISH-2 (Mar 26, 2026)
• WADA Prohibited List 2026 / Monitoring Program summary (NADA Germany)