Emerging · Viking Therapeutics

VK2735 vs Tirzepatide & Retatrutide

📄 5 PubMed citations

The peer-reviewed VENTURE trial, lined up beside tirzepatide and retatrutide - and why the viral “it wins” comparison doesn’t hold up once you check the trial lengths.

🔬 Unlike the viral threads, this page refuses to stack a 13-week VK2735 result against 48- and 72-week trials as if they were the same race - every number below is labeled with its trial length and dose.
14.7%
VK2735 mean loss at 13 weeks (VENTURE, 15 mg)
20.9%
Tirzepatide at 72 weeks (SURMOUNT-1, 15 mg)
24.2%
Retatrutide at 48 weeks (Phase 2, 12 mg)

How It Works

🧬
Dual GIP/GLP-1 agonist

VK2735 activates both the GLP-1 and GIP receptors - the same two-hormone approach as tirzepatide. Retatrutide adds a third target, the glucagon receptor, making it a triple agonist.

💉
Weekly injection (oral in development)

The VENTURE trial tested weekly subcutaneous VK2735. Viking is also developing an oral tablet form, but the peer-reviewed weight-loss data so far is from the injectable.

⏱️
Short trial, steep early curve

VENTURE ran only 13 weeks. Incretin weight curves are still descending at three months, so a 13-week number cannot be equated to tirzepatide’s 72-week or retatrutide’s 48-week endpoint.

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GI side effects, dose-titrated

Like every drug in this class, VK2735’s most common adverse events were gastrointestinal. They decreased in reported frequency after dose titration to steady state - not “near-placebo.”

What the Data Shows

VK2735 15 mg
13-week VENTURE (Phase 2)
14.7%
Semaglutide 2.4 mg
68-week STEP 1
14.9%
Tirzepatide 15 mg
72-week SURMOUNT-1
20.9%
Retatrutide 12 mg
48-week Phase 2
24.2%

Key Takeaways

✅ What We Know
  • In the peer-reviewed 13-week VENTURE Phase 2 trial, weekly subcutaneous VK2735 produced mean weight loss of 9.1% (2.5 mg) up to 14.7% (15 mg), versus 1.7% for placebo.
  • 93% of participants on active VK2735 lost at least 5% of body weight, compared with 12% on placebo.
  • VK2735 is a dual GIP/GLP-1 receptor agonist - the same receptor pair targeted by tirzepatide.
  • Tirzepatide reached 20.9% mean weight loss at 72 weeks (15 mg) in the SURMOUNT-1 Phase 3 trial.
  • Retatrutide, a triple GIP/GLP-1/glucagon agonist, reached 24.2% mean weight loss at 48 weeks (12 mg) in its Phase 2 trial.
  • VK2735’s adverse events were mainly gastrointestinal and decreased in frequency after dose titration to steady state.
⚠️ What We Don't Know
  • No head-to-head trial has compared VK2735 with tirzepatide or retatrutide - every cross-drug figure here comes from separate studies with different designs and durations.
  • VK2735’s published result is from 13 weeks; tirzepatide’s is 72 weeks and retatrutide’s is 48 weeks. Incretin weight curves are still falling at 13 weeks, so the numbers are not directly comparable.
  • Widely shared “17.5 mg / ~22% / week-33” figures for VK2735 are not in the peer-reviewed VENTURE publication; longer, higher-dose, and any head-to-head data have not yet been peer-reviewed.
  • The peer-reviewed trial did not show “near-placebo” tolerability - gastrointestinal events were the most common adverse events, though they eased after titration.
  • VENTURE excluded people with diabetes, so its results do not speak to blood-glucose or diabetes outcomes.
  • Long-term efficacy, safety, and durability of VK2735 remain unknown pending Phase 3 trials.

Frequently Asked Questions

Is VK2735 better than tirzepatide?

There is no head-to-head trial, so this cannot be answered yet. VK2735’s peer-reviewed VENTURE result - 14.7% mean weight loss at the top 15 mg dose - came from just 13 weeks, while tirzepatide’s 20.9% came from 72 weeks. Comparing the two directly is not scientifically valid until a head-to-head study reads out.

How much weight did people lose on VK2735?

In the 13-week VENTURE Phase 2 trial, weekly subcutaneous VK2735 produced 9.1% to 14.7% mean weight loss across doses (2.5-15 mg), versus 1.7% on placebo. 93% of treated participants lost at least 5% of their body weight.

Does VK2735 cause fewer side effects than tirzepatide?

The published VENTURE trial reported mainly gastrointestinal adverse events that decreased after dose titration - not the “near-placebo” tolerability sometimes claimed online. No trial has directly compared VK2735’s side-effect rates with tirzepatide’s.

What is the difference between VK2735, tirzepatide and retatrutide?

VK2735 and tirzepatide are dual GIP/GLP-1 receptor agonists. Retatrutide adds a third target, the glucagon receptor, making it a triple agonist. In separate trials, retatrutide showed the largest weight loss (24.2% at 48 weeks), but no study has compared the three directly.

Is VK2735 approved or available?

No. VK2735 is an investigational Viking Therapeutics compound still in clinical trials. It is not FDA-approved and is not sold as a prescription weight-loss drug. This page is educational information only, not medical advice.

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Peer-Reviewed References

Source 1
Weekly Subcutaneous VK2735, a GIP/GLP-1 Receptor Dual Agonist, for Weight Management: Phase 2, Randomized, 13-Week VENTURE Study
Obesity (Silver Spring) · 2026
PMID: 41508550
Source 2
Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1)
New England Journal of Medicine · 2022
PMID: 35658024
Source 3
Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial
New England Journal of Medicine · 2023
PMID: 37366315
Source 4
Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1)
New England Journal of Medicine · 2021
PMID: 33567185
Source 5
Future GLP-1 receptor co-agonists and their cardiac effects
Naunyn-Schmiedeberg's Archives of Pharmacology · 2026
PMID: 42768195
⚠️ Disclaimer

Educational purposes only. Not medical advice.

VK2735 is an investigational drug not approved by the FDA; nothing here is a recommendation to obtain or use it.

Cross-trial comparisons on this page are illustrative only - no head-to-head study of these drugs exists.