Investigational — not approved or available to prescribe.
Main trial result
20%
Stage
Phase 3
Timeline (not confirmed)
2027+ (estimated — not confirmed)
Form
Monthly injection
What it is
MariTide takes a completely different approach from other weight loss drugs. Tirzepatide switches the GIP receptor on. MariTide blocks it instead — the opposite strategy — while also switching on GLP-1. It is an antibody-peptide conjugate: an antibody joined to a peptide, a drug class of its own, quite unlike small molecules or peptide injections. It only needs an injection once a month, or less often. That could be transformative for sticking with treatment.
Why this matters:
Most GIP drugs switch the GIP receptor on, among them tirzepatide and retatrutide. MariTide blocks it instead. That proves GIP can be targeted in opposite directions. Monthly dosing could be transformative for how well people stick with treatment. These treatments are still under investigation, and results in larger trials may differ from early data.
Development stage and timeline
Current stage:
Phase 2 complete. Phase 3 has started. The 72-week chronic weight management studies are enrolling now, with three target dose arms: they start at 21mg and step up to 35mg, then 70mg.
Next milestone:
Phase 3 data expected 2027. Estimated approval: 2027+ (preliminary; not confirmed).
How it works
MariTide is an antibody-peptide conjugate. It blocks GIP receptors (as an antagonist) and switches on GLP-1 receptors (as an agonist) at the same time. That is the opposite of tirzepatide, which switches GIP on. Both approaches produce significant weight loss. So GIP appears to play a complex part in appetite, one that can be targeted from either direction. Monthly dosing is possible because of the antibody part, which stays in the body far longer than a peptide drug.
Timeline note: In Phase 2, weight kept falling throughout 52 weeks, with no plateau. That suggests longer treatment may produce greater loss
Phase 2 trial data by dose
In the Phase 2 trial, people were randomly assigned to different doses or to a dummy pill. Here is how much weight each dose group lost. Phase 3 data is pending.
| Dose | At 24 weeks | At 48 weeks |
|---|---|---|
| –% | –% | |
| –% | –% |
Side effects (early-stage data)
Frequencies from Phase 2 trial data. Final Phase 3 safety profile may differ.
Notable findings
- ✓Monthly dosing, or less often — people may stick with it far better than with weekly injections
- ✓Works differently from all current approved drugs — a new mechanism class
- ✓~17% weight loss in people with type 2 diabetes (Phase 2, 52 weeks)
- ✓Weight had not plateaued by 52 weeks in Phase 2 — suggesting potential for greater loss with longer treatment
What this tends to offer vs. what it involves
What this tends to offer
- ✓Up to ~20% weight loss in Phase 2 — comparable to tirzepatide
- ✓Once-monthly injection — could make sticking with treatment much easier
- ✓Antibody-based design behaves differently in the body
- ✓Weight not plateauing in Phase 2 suggests potential for longer-term benefit
What this involves
- Phase 3 still ongoing — not yet completed
- Antibody-peptide format is more complex than small molecules
- Long-term safety and cardiovascular outcomes not yet studied
- Approval 2027+ estimated — several years away
How it differs from approved drugs
MariTide differs in two ways. It is given monthly, not weekly. And it blocks the GIP receptor rather than switching it on. Every other approved or pipeline drug that acts on GIP switches it on, tirzepatide and retatrutide included. MariTide blocks it. That both approaches produce significant weight loss is scientifically surprising. It suggests GIP is more complex than was first thought.
Community insights
These are personal experiences shared in public online communities — not medical advice.
“The monthly injection is the defining feature. People on Wegovy or Zepbound report that weekly dosing becomes routine, but monthly would be easier still to keep up.”
“Blocking GIP intrigues followers who know the pharmacology, but what it means in the clinic, against drugs that switch GIP on, remains uncertain.”
Sources & references
- [1]Phase 2 randomised dose-finding studyAdults with obesity (with and without type 2 diabetes) · 52 weeksUp to ~20% weight loss (non-diabetic cohort) and ~17% (type 2 diabetes cohort) at 52 weeks. No weight plateau observed. Monthly dosing confirmed feasible.Nature Medicine / Amgen press release (2024) ↗