CT-388 is an experimental once-weekly injection from Roche, now also called enicepatide. It activates the same two receptors as Zepbound — GLP-1 and GIP — but is engineered to switch them on without switching them off. One clinical study has been published, and it is not approved anywhere.
The short version
| What it is | An experimental weekly injection for obesity |
| Also called | Enicepatide, CT388 |
| Maker | Roche (developed by Carmot Therapeutics) |
| Targets | GLP-1 and GIP receptors, signalling-biased |
| Status | Not approved. Phase 3, recruiting |
| Published result | Up to 8% weight loss at day 29 (phase 1) |
| Can you get it? | No |
Three names for one molecule
CT-388 is the development code, from Carmot Therapeutics, the company that created it. CT388 is the same code without the hyphen. Enicepatide is the international nonproprietary name, which is what the trial registry now uses.
Roche acquired Carmot, so a molecule that appears in older coverage as a small-biotech asset is now a large-pharma phase 3 programme. There is no brand name, because there is no approval.
What makes it different from Zepbound
Both aim at the same two receptors. The difference is in how they activate them.
When a drug switches on a receptor, the cell responds by pulling that receptor inside itself — a self-protective mechanism called internalisation, which takes the receptor temporarily out of service. CT-388 is engineered to produce a strong signal while causing minimal internalisation, on the theory that a receptor left on the cell surface keeps working.
Tirzepatide's advance was choosing which receptors to hit. CT-388's is changing how. Whether that translates into better results over a full course is unproven.
What has been measured
One clinical study is published: a phase 1 trial in healthy participants with overweight or obesity, testing single doses and four weekly doses. Mean weight change at day 29 was −4.7% to −8.0% across doses, against −0.5% on placebo. It was generally well tolerated, with most adverse events mild or moderate.
Read that carefully: twenty-nine days. The figures quoted for approved drugs — tirzepatide's 20.9%, semaglutide's 14.9% — are measured at 68 to 72 weeks. Putting 8% next to them without the timescale would be misleading by roughly a factor of eighteen in elapsed time.
What 8% in four weeks does suggest is a steep early trajectory. Where the curve ends is unknown, because no longer trial has reported.
Can you take it? No
CT-388 is not approved by any regulator, cannot be prescribed, and is not sold through any legitimate channel. It is in phase 3 and recruiting, so enrolling in a trial is the only route, and that is a conversation for a clinician.
Where to go next
The full CT-388 guide covers the mechanism and the trial in detail. If you want a drug you can actually take, the approved options are ranked in the best GLP-1 for weight loss, and the rest of the development field is in the GLP-1 pipeline tracker.
If you want the detail
CT-388 weight loss covers the day-29 figure and its caveat; CT-388 side effects covers what has and has not been published; and CT-388 vs Zepbound sets out the argument the molecule is making.
Scientific References
2 sources- 1
Chakravarthy MV, Rodriguez R, Hergarden A, et al.
Effects of CT-388, a once-weekly signaling-biased dual GLP-1/GIP receptor agonist, on weight loss and glycemic control in preclinical models and participants with obesity
Molecular Metabolism · 103 · 2026PMID: 41319798
NIH - 2
U.S. National Library of Medicine
ClinicalTrials.gov — enicepatide (CT-388): 7 registered studies, maximum phase 3, recruiting, lead sponsor Hoffmann-La Roche; read 13 August 2026
ClinicalTrials.gov · 2026
References open in a new tab. Content is reviewed against peer-reviewed literature as part of our editorial policy.
About the author
Editor, Modern Weight Science
Claudiu Gheorghe is the editor of Modern Weight Science. He is not a physician. His role is to synthesize peer-reviewed studies, clinical-trial data, and FDA prescribing information into clear, plain-language explanations, and to make sure every factual claim on the site traces back to a cited source. Any decision about starting, changing, or stopping a medication belongs with a licensed clinician who knows your history.
Every claim is checked against peer-reviewed research through our review process and fact-checking policy.
Frequently Asked Questions
What is CT-388?
An experimental once-weekly injection from Roche, also called enicepatide, that activates the GLP-1 and GIP receptors — the same targets as tirzepatide — but is engineered as a signalling-biased agonist, meaning it drives the signal while causing minimal receptor internalisation. It is in phase 3 and not approved anywhere.
Is CT-388 the same as enicepatide?
Yes. Enicepatide is the international nonproprietary name; CT-388 is the development code from Carmot Therapeutics, the company that created it. Roche acquired Carmot, so the same molecule appears under both names depending on how recent the source is. There is no brand name because there is no approval.
How much weight loss does CT-388 cause?
The only published clinical result is from a phase 1 trial: mean weight change of −4.7% to −8.0% at day 29 across doses, against −0.5% on placebo. That is a four-week figure and cannot be set beside the 20.9% and 14.9% quoted for tirzepatide and semaglutide, which are measured at 68 to 72 weeks.
How is CT-388 different from Zepbound?
It aims at the same two receptors but changes how it activates them. Ordinary agonists cause the receptor to be pulled inside the cell after signalling, taking it briefly out of service. CT-388 is engineered to signal strongly with minimal internalisation, on the theory that a receptor left on the surface keeps responding. Whether that produces better results over a full course is unproven.
Can I get CT-388?
No. It is not approved by any regulator, cannot be prescribed and is not legitimately sold. It is in phase 3 and recruiting, so joining a trial is the only route, which is a conversation for a clinician.
Continue learning
Where to read next
Not medical advice. This guide is for general education only. GLP-1 medications, dosing, and treatment suitability are decisions for you and a licensed clinician who knows your full medical history.