Amylin 355 (NN9638)_Dosage, benefits & legal status
Also known as NN9638, NN 9638, NNC0638-0355, amylin-355, amylin355
The amylin Novo wants to sell as a pill.
Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.
What is Amylin 355 (NN9638)?
Plain language first. The technical label stays, but it never stands alone.Overview
Amylin is a hormone your pancreas releases with insulin, and it tells the brain you have eaten enough. Drugs copying it are the current wave behind the GLP-1 medicines, and this site already covers ten of them. This one is worth its own page for a narrow reason: it is Novo Nordisk's attempt at an amylin you swallow. Making a peptide survive the stomach is hard, and that is why almost every drug in this family is an injection. Novo describes this one as a potential first and best in class oral amylin, and it is now in a phase 2 trial that tests the injection and the pill side by side in about 170 people. What does not exist yet is any result. No dose has been published, no weight-loss figure, and not even the molecule's structure. The company says it will present the phase 1 data at a conference in 2027.
Amylin 355 is an investigational long-acting amylin receptor agonist from Novo Nordisk, carried in company documents under the project code NN9638 and in trial records under the compound code NNC0638-0355. Novo's 2024 annual report describes it as an amylin analog developed for once-weekly subcutaneous treatment; the 2025 report's phase 1 table describes it as an amylin receptor agonist. No structure has been released: there is no residue count, no acylation, no bridge, no formula, no substance registry record and no international nonproprietary name. In the third quarter of 2026 the existing first-in-human trial was amended to add phase 2 evaluation of both subcutaneous and oral forms, with a readout expected in the second half of 2027.
What it's used for
Investigational for obesity and overweight. It is not approved anywhere, is not sold, and has no published results of any kind.
How does Amylin 355 (NN9638) work?
What it does in the body, and where.Eleven amylin pages now sit on this site, and the useful question is not how this one works, because that is the class mechanism, but what Novo is trying to do with it that the other ten do not. Novo answers that itself.
- 01What amylin doesThe pancreas releases amylin alongside insulin after a meal. It slows the stomach, blunts the glucagon rise that would otherwise push blood sugar up, and signals fullness through the brainstem. Copying it reduces how much people eat, and the class is being developed both on its own and alongside GLP-1 drugs because the two signals are complementary rather than redundant.
- 02Why an oral amylin is the hard versionPeptides are food as far as the gut is concerned: digestive enzymes cut them and the intestinal wall does not let much through. That is why almost every amylin drug in development is an injection. Making one work as a tablet takes either a chemical backbone that resists digestion or a formulation that opens absorption, and usually both. Novo has done this once already for semaglutide, so the ambition is credible on track record. The specific technology used here is not disclosed, and we are not assuming it is the same one.
- 03Novo's own three-way split, the reason this page existsAt its Capital Markets Day in September 2026 Novo positioned three amylin assets distinctly: cagrilintide as a first-in-class once-weekly amylin monotherapy, zenagamtide, the compound this site still files under amycretin, as a first- and best-in-class GLP-1 and amylin dual agonist across injectable and oral formats, and oral amylin 355 as a potential first and best in class oral amylin. So cagrilintide is the injectable monotherapy, zenagamtide is the dual agonist, and this is the oral monotherapy play. It is the only amylin on this site with a disclosed oral phase 2.
- 04Two amylin analogs at once, by designNovo gave its reasoning at a research event in June 2025: amylin monotherapy and GLP-1 combinations are both being explored for complementary effects, and amylin analogs have different profiles based on backbone and receptor selectivity. That is the closest thing to a stated rationale for running more than one. It also means the differences between them are in structure, and the structure of this one is not public.
- 05What is not known, stated plainlyNo residue count, no acylation, no bridge, no formula, no registry record, no nonproprietary name, no dose, no half-life, no weight figure, no tolerability data. The class playbook is published for its relatives, with specific fatty acid chains and bridging strategies described for cagrilintide, amycretin and petrelintide, and none of it is attributed to this compound. We are not borrowing it.
What else is it used for?
Each group carries its own evidence level.Approved means regulators have cleared it for that purpose. Investigational means it is in trials. Early research means it is being studied and is not established.
What the program is, and where it stands
Investigational- RegulatoryPhase 1 started September 2024 with 63 participants; phase 2 was added to the same trial in the third quarter of 2026, covering a subcutaneous and an oral form in around 170 people, with a readout expected in the second half of 2027.
- RegulatoryThere is no separate phase 2 trial record because Novo amended the existing first-in-human study rather than starting a new one, and the registry's last update predates the announcement.
- RegulatoryNovo describes it as an amylin analog developed for once-weekly subcutaneous treatment (2024) and as an amylin receptor agonist (2025).
- ReviewA 2026 peer-reviewed review independently names it as a long-acting amylin analog in Novo's pipeline, the only non-company confirmation of what it is.
Why it earns a page beside ten other amylin cards
none- RegulatoryNovo's own September 2026 positioning: cagrilintide is the first-in-class once-weekly amylin monotherapy, zenagamtide is the GLP-1 and amylin dual agonist across injectable and oral formats, and oral amylin 355 is a potential first and best in class oral amylin.
- lab-analysisIt is the only amylin on this site with a disclosed oral phase 2. Making a peptide work as a tablet is the hard problem in this class.
- RegulatoryNovo's stated reason for running more than one amylin analog: amylin analogs have different profiles based on backbone and receptor selectivity. The backbone of this one is not public.
- No dataA sibling program, amylin 1213, sits beside it in the same phase 1 listings. Novo has never said how the two differ, so no distinction should be invented.
What is not known, and what must not be borrowed
none- lab-analysisNo structure of any kind: no residue count, acylation, bridge, formula or molecular weight. The FDA substance registry returns nothing for either name, against a working control, and no nonproprietary name exists.
- No dataNo dose level has been published for any part of the program, and no half-life, exposure or tolerability figure either.
- No dataNo weight-loss result exists. Management's double-digit remark describes an aspiration for the oral form, not a measurement.
- No dataThe class structural playbook published for cagrilintide, amycretin and petrelintide is not attributed to this compound anywhere, and is not applied to it here.
- No dataNo delivery technology is named for the oral form in any Novo source. The absorption enhancer used for oral semaglutide is documented for oral zenagamtide and not for this compound.
Nothing is for sale, and the absence is unusually clean
none- No dataFour separate vendor-shaped searches returned no listing under Amylin 355, NN9638 or NNC0638-0355. Every result was for cagrilintide, eloralintide or natural amylin, all of which already have pages here.
- No dataThere is no product shape to describe at all, not even a pre-order or a research-use-only vial.
The number to watch for is one that does not exist. No weight-loss figure has ever been published for this compound, so anything quoted as its result has come from somewhere else. Two specific mix-ups are easy to make. Novo's Capital Markets Day slide on oral amylin 355 carries a weight-change chart, and the only legible curve on it is oral zenagamtide at 12 weeks, not this drug. Management's remark about meaningful double-digit weight loss is a statement of potential for the oral form, phrased as potential, and not a measurement. Second, the figure 170 should be handled carefully: Novo's head of development gave it for the trial that covers both routes, while the slide shows 170 against the oral comparison, so it should not be stated as the oral arm's size. Third, the oral formulation is often assumed to use the same absorption enhancer as oral semaglutide. No Novo source says so for this compound; that technology is documented for oral zenagamtide. Fourth, searches for a phase 2 trial record come up empty and the conclusion drawn is usually that the phase 2 does not exist. It does: Novo amended the existing phase 1 trial, and the registry has not caught up. Last, the compound code NNC0638-0355 appears in trial records while Novo's own documents use Amylin 355 and NN9638, and no single Novo document we could open prints both codes together.
The published record
0
Papers about Amylin 355 (NN9638)
Searched: amylin 355, NN9638, NNC0638-0355.
Left out: amylin 1213 (OBSERVED DISAMBIGUATION RISK: a SECOND Novo phase 1 amylin analog, code NN9839, listed as New in the 2025 annual report phase 1 table and sitting beside amylin 355 on the same Capital Markets Day slide. Novo has NEVER said how the two differ, so no distinction may be invented and the names must not be merged); NN9839 (the code for that sibling program, one digit family away from this compound's NN9638); cagrilintide (Novo's OTHER amylin, and the one with published data. Novo positions it as the first-in-class once-weekly amylin MONOTHERAPY while this compound is the oral monotherapy play. It has its own slug and a large literature); amycretin (now renamed zenagamtide, Novo's GLP-1 plus amylin DUAL agonist across injectable and oral formats, with its own slug. It is the compound whose oral weight-loss curve appears on the same Capital Markets Day slide as this one, and that curve must never be read as this drug's result); zenagamtide (the same molecule under its new name, which this site files under amycretin); petrelintide (a different company's amylin analog with its own slug and published phase 2 data); eloralintide (another company's amylin agonist with its own slug and an INN, unlike this compound); amylin (the natural 37-residue hormone, which has its own slug, plus the receptor class term returning the entire amylin literature); Novo Nordisk (a company name spanning a very large portfolio including at least four other amylin assets).
Europe PMC was searched on 9 November 2026 for these terms and returned nothing.
Counted from Europe PMC indexing, not read by a person.
At a glance
Four things to know about Amylin 355 (NN9638)
Evidence
Investigational
Category
Weight loss and metabolic
Common vial
Varies
Half-life
Not published
How much, and do you cycle it?
The range, and whether you take breaks.No human dose disclosed, once weekly for the injection. Continuous weekly dosing in the trial Trial dose
Trialed as an ongoing weekly treatment rather than in blocks. The phase 1 multiple ascending dose parts ran weekly dosing with measurements to week 20, and no planned break appears anywhere in the program.
How long does it stay in the body?
The half-life, and where the figure comes from.Not publishedNo figure
No half-life has been reported in any species. The phase 1 trial measures exposure as a secondary outcome and Novo says it will present that data at a conference in 2027. Once-weekly subcutaneous dosing implies a half-life on the order of days, and that is an inference from the dosing interval rather than a published figure.
You can compare this against the whole library to see where it sits.
How do I dose and price it?
Enter your vial and your dose. Pick a mix. We show the draw and the cost.The vial holds a fixed amount of drug. Adding more water does not make more drug, it just spreads it thinner, so you draw a bigger number on the syringe for the same dose.
Choose your mix
Measuring the water1 mL = one full 100-unit syringe.
How do you store it?
Before mixing, and after.Nothing to store: it is not sold anywhere.
Amylin 355 (NN9638) has never been marketed, so there is no vial, pen or bottle to keep at home. Supplies for a trial are made, stored and dispensed by the sponsor and the trial pharmacy under conditions set in the protocol. Anything offered for sale under this name did not come from that supply chain.
What are the side effects and cautions?
Known cautions and warnings for this compound.Who should avoid it
- Expecting any weight-loss number from it, since none has ever been published and management's double-digit remark is an aspiration rather than a result
- Reading figures from the chart on Novo's Capital Markets Day slide as this drug's results, because the only legible weight curve on that slide belongs to oral zenagamtide
- Assuming the oral form uses the absorption enhancer behind oral semaglutide, since no Novo source names any delivery technology for this compound
- Treating it as interchangeable with the sibling program Amylin 1213, because Novo has never said how the two differ
Stop and get help
- This exists only inside Novo-run trials, so there is no dose anyone can take or stop outside one
- Participants follow their trial's own stopping rules, and those are not public
Common effects
- Nothing has been published. The class norm is nausea while the dose is going up.
Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.
Is Amylin 355 (NN9638) approved?
And where the numbers on this page come from.No. Amylin 355 (NN9638) is not approved anywhere and is currently in company-run clinical trials. There is no legal route to obtain it outside a trial.
- Approval statusInvestigational
- RouteUnder the skin (subcutaneous) or by mouth; both are in the same phase 2 trial
- Checked6 November 2026
- DoseNo dose has been established in people.
- Vial sizeFrom what vendors typically list; not a recommendation.
- SourcesClinicalTrials.gov, the first-in-human trial (NCT06577766)Novo Nordisk annual report 2024, obesity pipelineNovo Nordisk annual report 2025, innovation and therapeutic focusPeptides, long-acting amylin-related peptides as therapies for obesity and type 2 diabetesNovo Nordisk Q3 2026 company announcement, advancement of the amylin 355 phase 2 programNovo Nordisk Q3 2026 earnings call, November 4, 2026
What has happened recently
Nothing is approved and nothing is filed. The program's shape is documented and its data is not. Novo's Q3 2024 presentation recorded the phase 1 initiation; the 2024 and 2025 annual reports both carry it in the phase 1 table; the June 2025 research event listed it as phase 1 ongoing beside a sibling called amylin 1213; and the Capital Markets Day of September 21, 2026 footnoted phase 2 as starting in the third quarter of 2026. **The reason no phase 2 trial record exists is documented rather than guessed.** Novo's own third-quarter announcement states that the ongoing trial has been amended to include phase 2 evaluation of subcutaneous and oral amylin 355, so there is one amended study rather than two new ones, and the registry's last update predates the announcement. One wrinkle worth knowing, from the same company on the same day: the announcement body describes an amended trial while its own highlights say an oral phase 2 trial was initiated. The most defensible reading is that the first-in-human study was expanded into phase 2 across both routes. On identity, the code chain has one weak link. NN9638 equals Amylin 355 on Novo's own documents, in both annual reports and in the standard code footnotes of at least two investor decks. NN9638 equals NNC0638-0355 is not stated in any single Novo document we could open; Novo writes the project name and code while the trial registry writes the compound code, and the equation rests on a commercial pipeline database plus the matching digits. We print the compound code because the trial record uses it, not because Novo has confirmed the link.
You can compare this against the whole library, or read how to check a seller.
What else is like Amylin 355 (NN9638)?
Others in Amylin analogs, side by side.If you're weighing Amylin 355 (NN9638), it's worth reading ASC36, AZD6234, and NN9662 (Triple) in the same class.
The amylin Novo wants to sell as a pill.
- Dose
- No human dose disclosed
- How often
- Once weekly for the injection
An experimental amylin drug from Hong Kong-listed Ascletis, with rat and monkey data only and an undisclosed structure.
- Dose
- No human dose disclosed
- How often
- Monthly injection or daily tablet (intended)
An experimental weekly fullness-hormone shot from AstraZeneca, tuned to the amylin receptor.
- Dose
- Once weekly in trials; milligram dose levels have not been publicly disclosed
- How often
- Weekly
Novo's other triple agonist, the one that hits amylin.
- Dose
- No dose disclosed in any trial record
- How often
- Once weekly
Guides for this compound
- How to Reconstitute a Peptide
Mix peptide powder with bacteriostatic water, step by step.
- How to Read an Insulin Syringe
Read the units, convert to millilitres, and draw the exact dose.
- mcg vs mg: The Peptide Dosing Mistake to Avoid
Your vial says mg and your protocol says mcg. Here is the conversion and how to check it.
- How to Read a Peptide COA
What the purity number does and does not tell you, and how to spot an edited report.
- How to Vet a Peptide Vendor
Independent COAs, HPLC purity, and the red flags that mean walk away.
Sources
- ClinicalTrials.gov, the first-in-human trial (NCT06577766)(2026)Organization study ID NN9638-7569. A randomized, placebo-controlled, double-blinded study of single and multiple subcutaneous doses of NNC0638-0355 in people with overweight or obesity. Phase 1, active and not recruiting, 63 participants actual, started September 3, 2024, primary completion estimated October 11, 2027. One single ascending dose part and four multiple ascending dose parts, each against matching placebo. Primary outcome is a count of treatment-emergent adverse events; secondary outcomes are exposure measures. Eligibility is 18 to 55 with a body mass index of 25.0 to 34.9, HbA1c below 6.5%, and vitamin D, parathyroid hormone and total calcium in range. Three things worth noting: no dose level is stated anywhere in the record, no receptor target or mechanism is named anywhere on the page, and the record's last update of September 30, 2026 predates the November announcement, so it still reads phase 1 and subcutaneous only.
- Novo Nordisk annual report 2024, obesity pipeline(2024)The richest sponsor description of the molecule: the pipeline row gives Amylin 355, NN9638, obesity, phase 1, and calls it an amylin analog developed for once-weekly subcutaneous treatment. The report's research progress text records that the phase 1 first-in-human dose trial was initiated. This is also the earlier of the two annual reports that print the project name and the code on the same row, and that is the basis for treating them as the same thing.
- Novo Nordisk annual report 2025, innovation and therapeutic focus(2025)The phase 1 table reads Amylin 355, NN9638, obesity, amylin receptor agonist, with the phase progress column blank. Note what is absent: no formulation, no structure, no dose and no data. Both annual reports describe the compound as developed for once-weekly subcutaneous treatment with no mention of an oral form. Oral appears in Novo materials only from September 2026 onward. Card text citing these reports should not imply that oral was always planned.
- Peptides, long-acting amylin-related peptides as therapies for obesity and type 2 diabetes(2026)Volume 196, article 171480, by Bailey, Flatt and Conlon. The only peer-reviewed source we found that names this compound: it calls amylin-355 another long-acting amylin analog in the Novo pipeline of weight-reducing medicines, formulated for once-weekly subcutaneous injection, and in phase 1. That matters because it is independent confirmation that the compound is a peptide analog rather than something else. The review also sets out the class structural playbook, including specific fatty diacid chains and bridging strategies for its relatives, and attributes none of it to this compound.
- Novo Nordisk Q3 2026 company announcement, advancement of the amylin 355 phase 2 program(2026)The document that explains why no phase 2 trial record exists. It states that the ongoing clinical trial with amylin 355 has been amended to include phase 2 evaluation of subcutaneous and oral amylin 355 in people with overweight or obesity, and that Novo expects to present data from the phase 1 single- and multiple-ascending dose cohorts at a scientific conference in 2027. So the phase 1 data exists and is embargoed to a conference rather than absent. The same document's highlights describe an oral phase 2 trial as initiated, and that reads differently from an amended trial.
- Novo Nordisk Q3 2026 earnings call, November 4, 2026(2026)Read as a transcript published by a financial site rather than on Novo's own domain, so treat the words as management statements and the host as third-party. Novo's head of development said amylin 355 recently advanced into phase 2 with an expected readout in the second half of 2027, and that the trial investigates both subcutaneous and oral amylin 355 in around 170 patients with overweight and obesity. He added that for the oral formulation the company sees potential to deliver meaningful double-digit weight loss with potentially fewer side effects. That last part is an aspiration and not a result; no weight figure has been reported for this compound at any dose.