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GLP-1/amylin dual receptor agonist peptide (investigational) · safety
Zenagamtide side effects
The zenagamtide side effects reported most often are stomach or gut symptoms after oral dosing and stomach or gut symptoms after injected dosing. The full list is below, with the cited trial report cited at the bottom of the page.
These effects tend to cluster at the start and after each dose increase, and to settle down while the dose stays the same.
Zenagamtide, once called Amycretin, is an experimental weight-loss drug being tested as an injection and a pill. It acts on GLP-1 and amylin signals. Sellers offer unapproved versions to people seeking weight loss, often under the older Amycretin name.
Early trials reported average weight loss with injected and oral forms. Phase 3 trials are registered, but no phase 3 result is available.
At a glance
Common reactions listed
2
Serious reactions listed
0
Boxed warning
No label exists
Strongest source
Human trial
Common reactions
The full list, as reported across the available trial evidence. There is no approved label to read frequency bands off, so these are the trials’ own figures.
| Reaction | Frequency |
|---|---|
| Stomach or gut symptoms after oral dosing | 180 of 364 treatment-emergent events; 72 of 89 participants with any event had at least one stomach or gut event |
| Stomach or gut symptoms after injected dosing | The most common event class; most events were mild or moderate |
When to seek medical care
The trial report does not give a separate list of serious reactions. There is also no approved label. That gap does not mean serious reactions cannot happen. This compound has been studied in fewer people and for less time than an approved drug.
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When these effects tend to occur
GLP-1 labels and trial reports place stomach and gut effects most often at the start and after dose increases. A later increase can bring that early pattern back.
The same sources describe most of these effects as temporary — showing up after a step and easing off while the dose stays put. That is the pattern across whole trial populations. It is not a promise about you, and the sources do not commit to how long the easing takes.
Common questions
How long do zenagamtide side effects last, and do they go away?
The sources do not commit to a set number of days. What they describe is a pattern — reactions cluster after you start and after each increase, then ease while the dose is held steady. Any page quoting an exact number of days is quoting something the sources do not say.
What are the most common zenagamtide side effects?
Stomach or gut symptoms after oral dosing and stomach or gut symptoms after injected dosing — the table above has the rest, each with its frequency band and source.
Does zenagamtide have a boxed warning?
No, because a boxed warning is part of an FDA-approved label and zenagamtide has no approved label. That reflects what regulatory review has and has not covered, not a finding that serious risks were looked for and ruled out.
Can the zenagamtide dose be lowered if side effects are hard to tolerate?
That decision belongs to the prescribing clinician. No approved schedule exists for this compound, so there is no labeled framework for adjusting a dose. That leaves the prescriber as the only place the decision can sit.
Does zenagamtide cause hair loss?
Hair loss is not among the reactions listed on this page for zenagamtide, because the cited trial report cited here does not carry it. Anything missing from the tables is outside what can be sourced here rather than ruled out, and a symptom that worries you belongs with a clinician.
Is fatigue a listed zenagamtide side effect?
No — the cited trial report cited here does not list it. That describes what was reported, not proof that the symptom cannot happen.
Is constipation a listed zenagamtide side effect?
Not separately. If a source groups stomach and gut events together, this page keeps that group intact. It does not invent named reactions the source never listed.
What should someone do about a serious zenagamtide reaction?
Contact a clinician promptly, and emergency services if symptoms are severe or getting worse quickly. The available sources do not list any reactions as separately serious. That means there is no early-warning list here—not that serious reactions are impossible.
Do the frequencies on this page mean the chance it happens to one person?
No. These figures describe groups in a study. A band shows how often a reaction appeared under that trial’s conditions. It cannot predict what will happen to one person.
Related
The schedule these reactions were recorded against, the comparisons, and the sourcing rules behind every grade on this page.
- Knop FK et al. Oral amycretin in adults with overweight or obesity: phase 1 trial (NCT05369390, PMID 40550229)retrieved 2026-08-17Human trial
- Jastreboff AM et al. Subcutaneous amycretin in adults with overweight or obesity: phase 1b/2a trial (NCT06064006, PMID 40550231)retrieved 2026-08-17Human trial