Recall(New to the series?)
Dual agonists combine GLP-1R activation with a second receptor — either GIPR (GIP) or GCGR (glucagon). Adding GIP amplifies appetite suppression and fat metabolism through mechanisms that synergize with GLP-1. Adding glucagon raises energy expenditure and drives liver fat mobilization. For the full receptor breakdown, see The Receptor Game.
The dual agonist family exists because single GLP-1 agonists hit a ceiling. Semaglutide at 2.4mg produces ~15% weight loss — meaningful, but not enough for a significant portion of patients with severe obesity. Dual agonism was the first approach to break past that ceiling in the clinic, not just in rodent models.
The family splits into two mechanistic branches: GLP-1/GIP (commercially proven, led by tirzepatide) and GLP-1/glucagon (mechanistically distinctive, proving itself in Phase 3). Each takes a different theory of how to surpass semaglutide.
GLP-1 / GIP dual agonists
Tirzepatide — Eli Lilly
At a glance
| Brand names | Mounjaro (T2D), Zepbound (obesity) |
| Targets | GLP-1R + GIPR |
| Developer | Eli Lilly |
| Modality | SC injection, once-weekly |
| Approval status | Approved — US (Mounjaro 2022, Zepbound 2023) |
| Key efficacy | 20.9% weight loss at 72 weeks (15mg, SURMOUNT-1) |
| Indications | Type 2 diabetes, obesity |
How it works
A synthetic peptide engineered to activate both GLP-1R and GIPR with roughly equal potency from a single molecule. The dual receptor engagement is built into the peptide's amino acid sequence — not a conjugate of two separate drugs. Half-life approximately 5 days, enabling once-weekly dosing.
GLP-1R drives appetite suppression, insulin secretion, and gastric slowing. GIPR engagement in fat tissue and the brain synergizes with GLP-1's satiety signal in ways that were not predicted before the clinical data — early research had suggested GIP agonism might be unhelpful or counterproductive for weight loss. Tirzepatide's Phase 3 results forced a revision of that assumption.
Trial data
SURMOUNT-1 (obesity, non-diabetic): 20.9% mean weight loss at 72 weeks on 15mg. ~37% of participants lost more than 25% of body weight — a figure previously only associated with bariatric surgery. The 5mg and 10mg doses showed 15% and 19.5% respectively, all outperforming semaglutide 2.4mg's 15%.
SURPASS trials (T2D): 1.5–2.4% HbA1c reduction depending on dose, outperforming both insulin glargine and semaglutide.
SURMOUNT-5 (head-to-head vs semaglutide 2.4mg, 2025): tirzepatide produced ~47% greater relative weight loss — the first large-scale direct comparison confirming dual agonism's superiority over the single-receptor standard of care.
Dosing and administration
2.5mg weekly → 5mg → 7.5mg → 10mg → 12.5mg → 15mg maintenance over ~20 weeks. Slow titration to manage GI tolerability. Single-dose autoinjector pen.
Development status
Fully approved and commercially available. Cardiovascular outcome trial (SURMOUNT-MMO) ongoing, results expected 2027. Additional indications in development including sleep apnea (approved 2024) and heart failure.
Safety profile
GI side effects — nausea, vomiting, diarrhea — most common during titration, pattern similar to semaglutide. Same thyroid C-cell black box warning as class. Heart rate increase of ~2–4 bpm (class effect). No novel safety signals identified in post-marketing surveillance.
VK2735 — Viking Therapeutics
At a glance
| Brand names | Not yet approved |
| Targets | GLP-1R + GIPR |
| Developer | Viking Therapeutics |
| Modality | SC injection weekly / oral tablet (separate formulations) |
| Approval status | Phase 3 |
| Key efficacy | 14.7% at 13 weeks (sub-Q Phase 2); ~8.2% at 13 weeks (oral Phase 2) |
| Indications | Obesity, T2D |
How it works
GLP-1/GIP dual agonist with the same mechanistic approach as tirzepatide — simultaneous GLP-1R and GIPR activation from a single peptide. The differentiation is in delivery: Viking is developing both a subcutaneous injectable and a separate oral formulation, the latter being the more strategically significant.
If the oral dual agonist formulation holds up in Phase 3, VK2735 would be the first oral drug combining the efficacy profile of dual receptor agonism with the convenience of a pill — a combination no currently approved drug offers.
Trial data
VENTURE (sub-Q Phase 2, obesity): 14.7% weight loss at 13 weeks. Short duration makes direct comparison to 72-week tirzepatide data difficult, but the trajectory suggests competitive efficacy at full trial length.
ACHIEVE-1 (oral Phase 2): ~8.2% weight loss at 13 weeks — strong for an oral agent at this timepoint, better than Rybelsus (oral semaglutide) at comparable duration.
Dosing and administration
Sub-Q: once-weekly injection. Oral: once-daily tablet. Specific titration schedules for Phase 3 not yet fully public.
Development status
| Milestone | Status |
|---|---|
| Sub-Q Phase 2 | Complete — 14.7% at 13 weeks |
| Oral Phase 2 | Complete — 8.2% at 13 weeks |
| Sub-Q Phase 3 | Enrolling |
| Oral Phase 3 | Enrolling |
| FDA filing | ~2027 estimated |
Safety profile
Phase 2 GI profile consistent with GLP-1/GIP class. No new safety signals identified. Full tolerability picture pending Phase 3 at longer duration and larger scale.
Olatorepatide — Hansoh Pharma / Regeneron
At a glance
| Brand names | Not yet approved |
| Targets | GLP-1R + GIPR |
| Developer | Hansoh Pharma / Regeneron |
| Modality | SC injection, once-weekly |
| Approval status | Phase 3 |
| Key efficacy | 19.3% weight loss at 48 weeks (Phase 3, Chinese cohort) |
| Indications | Obesity |
How it works
GLP-1/GIP dual agonist with the same mechanistic framework as tirzepatide. The Regeneron partnership provides US development resources and commercial infrastructure for a drug that originated from a Chinese pharmaceutical company — a model increasingly common in the GLP-1 pipeline as Chinese pharma invests heavily in the space.
Trial data
OASIS-1 (Phase 3, Chinese cohort): 19.3% weight loss at 48 weeks — competitive with tirzepatide's 19.5% at 10mg and 72 weeks, though different trial populations and durations make direct comparison imprecise. Global Phase 3 trials ongoing.
Dosing and administration
Once-weekly subcutaneous injection. Full titration schedule to be confirmed in global Phase 3 protocol.
Development status
| Milestone | Status |
|---|---|
| Phase 3 (China) | Data reported — 19.3% at 48 weeks |
| Global Phase 3 | Enrolling |
| FDA filing | Timeline pending global data |
Safety profile
GI profile consistent with GLP-1/GIP class based on Phase 3 Chinese cohort data. Global safety database pending.
GLP-1 / glucagon dual agonists
Survodutide — Boehringer Ingelheim / Zealand Pharma
At a glance
| Brand names | Not yet approved |
| Targets | GLP-1R + GCGR |
| Developer | Boehringer Ingelheim / Zealand Pharma |
| Modality | SC injection, once-weekly |
| Approval status | Phase 3 |
| Key efficacy | ~19% weight loss at 46 weeks (Phase 2, obesity) |
| Indications | Obesity, MASH |
How it works
GLP-1/glucagon dual agonist — a mechanistically distinct approach from the GLP-1/GIP branch. GLP-1R drives appetite suppression and insulin secretion. GCGR activation adds energy expenditure (raises resting metabolic rate) and hepatic fat oxidation — the liver-targeting effect that makes this class particularly relevant for MASH.
Where GIP co-agonism amplifies GLP-1's appetite signal, glucagon co-agonism adds a metabolic rate component that GLP-1 alone doesn't provide. This theoretically addresses the body's adaptive reduction in energy expenditure during weight loss — the mechanism that causes plateau.
Trial data
Phase 2 (obesity): ~19% weight loss at 46 weeks — competitive with tirzepatide's Phase 2 numbers.
Phase 2 MASH: ~67% of patients achieved MASH resolution without worsening of fibrosis — a striking number in a disease where options have historically been limited to lifestyle modification. The glucagon agonism component is believed to drive this through direct hepatic fat mobilization.
Dosing and administration
Once-weekly subcutaneous injection. Titration schedule involves slower escalation than GLP-1-only drugs due to glucagon's glucose-raising effect requiring careful balance against GLP-1's insulin-stimulating effect.
Development status
| Milestone | Status |
|---|---|
| Phase 2 obesity | Complete — ~19% weight loss |
| Phase 2 MASH | Complete — ~67% resolution |
| Phase 3 obesity | Enrolling |
| Phase 3 MASH | Enrolling |
| FDA filing | ~2027 estimated |
Safety profile
GI profile similar to GLP-1 class. The glucagon component raises theoretical hyperglycemia concern in non-diabetic patients — manageable within the dose range tested in Phase 2 through careful titration. Heart rate elevation similar to class effects. Phase 3 will be the definitive tolerability read.
Pemvidutide — Altimmune
At a glance
| Brand names | Not yet approved |
| Targets | GLP-1R + GCGR |
| Developer | Altimmune |
| Modality | SC injection, once-weekly |
| Approval status | Phase 2 complete, Phase 3 pending |
| Key efficacy | ~15.6% weight loss at 48 weeks (Phase 2 MOMENTUM) |
| Indications | Obesity, MASH |
How it works
GLP-1/glucagon dual with a particular focus on the MASH indication — same mechanistic approach as survodutide but with a development strategy that prioritizes liver disease alongside obesity. Glucagon agonism drives hepatic fat oxidation directly, making this class more liver-targeted than GLP-1/GIP dual agonists.
Trial data
MOMENTUM (Phase 2, obesity): ~15.6% weight loss at 48 weeks — below survodutide's Phase 2 numbers, but with a MASH-focused trial design that wasn't optimized purely for weight loss endpoint.
IMPACT NASH (Phase 2, MASH): Significant hepatic fat reduction and improvement in liver histology. Moving toward Phase 3 with MASH as the primary indication.
Dosing and administration
Once-weekly subcutaneous injection. Titration details to be confirmed in Phase 3 protocol.
Development status
| Milestone | Status |
|---|---|
| Phase 2 MOMENTUM (obesity) | Complete — 15.6% at 48 weeks |
| Phase 2 IMPACT NASH | Complete |
| Phase 3 initiation | Pending — MASH primary indication |
| FDA filing | ~2028 estimated |
Safety profile
GI profile consistent with GLP-1 class. Glucagon component managed through titration. No novel safety signals in Phase 2.
Mazdutide — Innovent Biologics / Eli Lilly
At a glance
| Brand names | Not yet globally branded |
| Targets | GLP-1R + GCGR |
| Developer | Innovent Biologics / Eli Lilly |
| Modality | SC injection, once-weekly |
| Approval status | Approved — China 2025. Not yet approved US/EU |
| Key efficacy | ~14.5% weight loss at 24 weeks (Phase 3 GLORY, China) |
| Indications | Obesity |
How it works
GLP-1/glucagon dual agonist — the first drug of this type to receive any regulatory approval, obtained in China in 2025. Same mechanistic framework as survodutide and pemvidutide: GLP-1R for appetite and insulin, GCGR for energy expenditure and hepatic fat. Developed by Innovent with Eli Lilly's involvement in the partnership.
Trial data
GLORY trials (Phase 3, China): ~14.5% weight loss at 24 weeks — shorter trial duration than Western comparators, so the 24-week number likely understates the full efficacy potential at 48–72 weeks.
Dosing and administration
Once-weekly subcutaneous injection. China-approved dosing protocol established; global dosing pending Phase 3.
Development status
| Milestone | Status |
|---|---|
| China approval | 2025 |
| Global Phase 3 | Status pending |
| FDA filing | Timeline not public |
Safety profile
Phase 3 data from China consistent with GLP-1/glucagon class profile. Full global safety database pending.
What defines this family
Dual agonists reliably outperform single GLP-1 agonists on weight loss — the GLP-1/GIP branch reaches ~19–21% in well-powered Phase 3 data, the GLP-1/glucagon branch ~19% in Phase 2. The mechanism differences matter clinically: GIP co-agonism adds adipose tissue and brain effects that amplify appetite suppression, glucagon co-agonism adds metabolic rate and liver fat targeting that GIP doesn't provide.
The SURMOUNT-5 head-to-head (tirzepatide vs semaglutide, 2025) settled the GLP-1/GIP vs single agonist debate clearly — ~47% greater relative weight loss. The GLP-1/glucagon vs GLP-1/GIP comparison is the next open question, and no head-to-head data exists yet.
Summary(Family summary)
Tirzepatide is the established dual agonist — approved, proven, currently the efficacy standard. VK2735's oral dual formulation is the most strategically differentiated pipeline asset if Phase 3 holds. Survodutide leads the GLP-1/glucagon branch with strong MASH data alongside competitive weight loss. Mazdutide is the first GLP-1/glucagon approval globally (China). The head-to-head between GLP-1/GIP and GLP-1/glucagon dual agonism is the open question this family will answer over the next 2–3 years.