Insulin Efsitora Alfa (Onswik)_Dosage, benefits & legal status
Also known as Onswik, insulin efsitora alfa-gobe, efsitora
Approved, not yet available, and honest about type 1 on its own label.
Common vial size is what vendors typically sell, not a recommendation. Enter your own vial in the calculator.
What is Insulin Efsitora Alfa (Onswik)?
Plain language first. The technical label stays, but it never stands alone.Overview
This is the second once-weekly insulin to be approved in the United States, and as of now you cannot get it: the FDA approved it in September 2026 and the manufacturer said availability would follow in the coming months. Two things make it worth reading about anyway. It is built completely differently from the other weekly insulin, by bolting insulin onto a piece of an antibody, and it lasts far longer, about 17 days rather than about one week. Also, unlike its competitor, its label says in plain words that it is not recommended in type 1 diabetes because of the risk of severe low blood sugar, and prints the numbers: 10 percent against 3 percent.
Insulin efsitora alfa is a once-weekly basal insulin built as a fusion protein: a single-chain insulin joined through a peptide linker to a human IgG antibody Fc domain, assembled as a disulfide-linked dimer of roughly 64 kilodaltons and produced in mammalian cell culture. The Fc domain is what gives it persistence, by the same recycling route that keeps antibodies in circulation for weeks. The label states a steady-state elimination half-life of approximately 17 days, independent of dose, the longest of any insulin product. The approved indication is an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes, with an explicit limitation of use against type 1.
What it's used for
As an adjunct to diet and exercise to improve blood sugar control in adults with type 2 diabetes. The label states it is not recommended in type 1 diabetes.
How does Insulin Efsitora Alfa (Onswik) work?
What it does in the body, and where.This is the most unusual insulin on the site, because most of the molecule is not insulin at all. It is an antibody fragment carrying an insulin payload.
- 01Insulin welded to an antibody tailOrdinary insulin is two separate chains. Here the chains are fused into one, and that single-chain insulin is joined through a peptide linker to the Fc domain of a human IgG antibody. The finished product is a disulfide-linked dimer of about 64 kilodaltons, so the insulin portion is a small part of a large protein, and it is grown in mammalian cells rather than synthesized.
- 02Borrowing the trick that keeps antibodies aroundAntibodies persist in blood for weeks because a receptor inside cells catches them, rescues them from degradation and returns them to circulation. An Fc domain inherits that recycling. Where icodec stays in the bloodstream by clinging to albumin, this molecule stays by being treated as an antibody. The result is a steady-state half-life the label gives as approximately 17 days, longer than any other insulin.
- 03Why 17 days makes dosing a safety questionA longer half-life means steadier levels and more forgiveness about timing. It also means errors are durable. The label's warning 5.1 is Hypoglycemia Due to Medication Errors and Accidental Overdose, ranked ahead of hypoglycemia in general, and the product comes in two concentrations, U-500 and U-1,000, with different step sizes. Having two strengths of a drug this concentrated and this long-lasting is a safety design problem rather than a convenience feature.
- 04The type 1 result, stated on its own labelIn type 1 diabetes, where there is no residual insulin of the body's own to buffer a mismatch, the 52-week comparison against daily degludec found severe low blood sugar in 10 percent of patients against 3 percent. The label responds with a limitation of use and a named warning section. That is a more candid treatment of the same class problem than the other once-weekly insulin's label gives, and it is the single most useful thing about reading these two side by side.
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.
Approved, and not yet on pharmacy shelves
FDA-approved- RegulatoryFDA-approved in September 2026 for adults with type 2 diabetes, on the first review cycle.
- No dataAvailability was described by the manufacturer as expected in the coming months, with no date given, and we found no launch announcement since. There is no DailyMed entry for the product.
The type 1 limitation, printed on the label
FDA-approved- RegulatoryThe label carries a limitation of use: not recommended in type 1 diabetes due to increased risk of severe hypoglycemia.
- Human trialSection 5.2 reports level 3 severe hypoglycemia in 10 percent of patients against 3 percent on daily insulin degludec over 52 weeks.
- No dataThe other once-weekly insulin showed a comparable type 1 signal in its own trial, and its label does not mention type 1 at all. The two labels handle the same class problem differently.
Why the half-life drives the warnings
FDA-approved- RegulatorySteady-state elimination half-life of approximately 17 days, independent of dose. This is the longest-acting insulin product.
- RegulatoryWarning 5.1 is about medication errors and accidental overdose, placed ahead of general hypoglycemia, and the product ships in two concentrations with different step sizes.
The first thing to get right is that this is not a version of the other once-weekly insulin, and neither is a biosimilar of the other. They are separate molecules with separate original applications: one is a two-chain analog held in circulation by binding albumin with a half-life of about a week, the other is a 64 kilodalton antibody-fusion protein recycled like an antibody with a half-life of about 17 days. Even where their substitutions look similar they diverge, and the fusion protein replaces the very lysine that the other depends on for its fatty acid. The second error is assuming approval means availability. It is approved and not yet sold, so a product offered under this name today did not come from the approved supply chain. The third is reading the label's type 1 limitation as a quirk of this drug. Both once-weekly insulins showed a type 1 hypoglycemia signal; this is the one that says so.
The published record
Papers and trials about Insulin Efsitora Alfa (Onswik)
Searched: efsitora, insulin efsitora alfa, Onswik, QWINT.
Left out: insulin (tens of thousands of unrelated records; the single most important rejection here); basal insulin (a class term, not this molecule); once-weekly insulin (also matches insulin icodec, which has its own slug); Fc fusion (a formulation approach shared with romiplostim and many unrelated biologics, and romiplostim has its own slug); Eli Lilly (a company name spanning an entire portfolio).
40 papers tagged human · 18 not reviews or lab · 12 clinical trial publications
5 registered trials · 5 with posted results
Furthest stage reached: Approved in the US
Counted from Europe PMC indexing, not read by a person; a human tag can land on reviews, commentary or lab papers; clinical trial publications is the narrower count.
At a glance
Four things to know about Insulin Efsitora Alfa (Onswik)
Evidence
FDA-approved
Category
Weight loss and metabolic
Common vial
Varies
Half-life
About 17 days
How much, and do you cycle it?
The range, and whether you take breaks.100 units a week to start, once weekly. Continuous weekly dosing FDA label
Basal insulin replacement is continuous treatment for a chronic condition. No cycling scheme applies.
How long does it stay in the body?
The half-life, and where the figure comes from.About 17 daysFDA label
Geometric mean steady-state elimination half-life of approximately 17 days, coefficient of variation 26 percent, independent of dose. The longest half-life of any insulin product, and roughly two and a half times that of the other once-weekly insulin. It is the reason the label leads its warnings with medication errors and accidental overdose.
Source: Onswik prescribing information, section 12.3
You can compare this against the whole library to see where it sits.
How is it given?
Dosing context and source notes.Supplied as a pen or prefilled syringe, so there is nothing to mix.
Label dose: 100 units per week.
100 units once weekly is the label's fixed-dosage starting point for someone not already on insulin. The alternative flexible regimen starts with a one-time 300-unit dose in week one and then 100 units in week two. There is no maximum; the dose is individualized. The U-500 pen delivers 5-unit steps and the U-1,000 pen 10-unit steps. A missed dose may be given within 4 days. These are the label's figures, recorded so a reader can recognize them, not guidance to act on.
How do you store it?
Before mixing, and after.Follow the storage on the product label.
Insulin Efsitora Alfa (Onswik) is supplied as a finished product, so its label sets the storage. Pens, prefilled syringes, implants, tablets and ready-made solutions are used as supplied. Kits that include a powder are mixed just before the dose and usually used straight away, not kept for weeks. Many injectable products go in the fridge and must not be frozen, while others are kept at room temperature, so check the pack or ask the pharmacist.
What are the side effects and cautions?
Known cautions and warnings for this compound.Who should avoid it
- Type 1 diabetes: the label states it is not recommended, due to increased risk of severe hypoglycemia
- Episodes of low blood sugar, and known hypersensitivity to the product
- Treating it as a version of the other once-weekly insulin: different molecule, different half-life, different pen strengths
Stop and get help
- Signs of severe low blood sugar, such as confusion, seizure or loss of consciousness, since that is an emergency
- Signs of a systemic allergic reaction
Common effects
- Low blood sugar, the expected effect of any insulin given in excess of need
- Injection-site reactions
Where this page says nothing is established, that means nobody has studied it, not that a compound is safe.
Is Insulin Efsitora Alfa (Onswik) approved?
And where the numbers on this page come from.Yes. Insulin Efsitora Alfa (Onswik) is FDA approved and available on prescription in the United States.
- Approval statusFDA-approved
- RouteUnder the skin (subcutaneous)
- Checked30 October 2026
- DoseFrom the drug label. The manufacturer tested this range and a regulator reviewed it.
- Vial sizeFrom what vendors typically list; not a recommendation.
- Sources
What has happened recently
FDA-approved in September 2026 for adults with type 2 diabetes, on the first review cycle. It is approved and not yet marketed: the manufacturer's own medical information stated that availability in the United States was expected in the coming months without giving a date, and we found no launch announcement since. There is no DailyMed entry for it, and the prescribing information is published on the manufacturer's own site. The label carries a limitation of use stating it is not recommended in patients with type 1 diabetes mellitus due to increased risk of severe hypoglycemia, and a dedicated warning, section 5.2, Severe Hypoglycemia in Patients with Type 1 Diabetes Mellitus, printing the comparison with insulin degludec. There is no boxed warning. Worth noting against the other once-weekly insulin on this site: both showed a type 1 hypoglycemia signal, and only this label says so.
You can compare this against the whole library, or read how to check a seller.
What else is like Insulin Efsitora Alfa (Onswik)?
Others in Weight loss and metabolic, side by side.If you're weighing Insulin Efsitora Alfa (Onswik), it's worth reading Macupatide (LY3532226), Nisotirostide (LY3457263), and Semaglutide in the same class.
Approved, not yet available, and honest about type 1 on its own label.
- Dose
- 100 units a week to start
- How often
- Once weekly
The experiment that isolates what GIP does.
- Dose
- No established dose
- How often
- Not established
A gut-hormone analog that only works as an add-on.
- Dose
- No established dose
- How often
- Not established
The drug in Ozempic and Wegovy: a weekly shot that curbs hunger for steady weight loss.
- Dose
- 0.25 up to 2.4 mg per week (start low, increase slowly)
- How often
- 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.
- Semaglutide vs Tirzepatide vs Retatrutide
One receptor, two, or three. Mechanism, trial weight loss, side effects, and real cost.
Sources
- Onswik (insulin efsitora alfa-gobe) prescribing information, Eli Lilly(2026)The label itself, published by the manufacturer because there is no DailyMed entry for this product. Indication verbatim: an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus. Limitation of use verbatim: not recommended for use in patients with type 1 diabetes mellitus due to increased risk of severe hypoglycemia. Section 5.2, Severe Hypoglycemia in Patients with Type 1 Diabetes Mellitus, reports that the incidence of level 3 severe hypoglycemia was higher on this drug than on insulin degludec, 10 percent against 3 percent over 52 weeks. Warning 5.1 is Hypoglycemia Due to Medication Errors and Accidental Overdose. No boxed warning. Section 12.3 gives a geometric mean steady-state elimination half-life of approximately 17 days with a coefficient of variation of 26 percent, independent of dose. Dosing: recommended starting dosage 100 units once weekly, or a flexible option with a one-time 300-unit first dose then 100 units; U-500 KwikPen delivers 5-unit increments and U-1,000 KwikPen delivers 10-unit increments, both 3 mL; a missed dose may be given within 4 days.
- Eli Lilly announcement of FDA approval(2026)The manufacturer's approval announcement, cited for the approval and the indication as the company stated them, and for the fact that the product is a once-weekly basal insulin for adults with type 2 diabetes. Availability was described as following the approval rather than coinciding with it.
Beyond these, 68 records are indexed. Browse the records