The U.S. Food and Drug Administration has approved Onswik (insulin efsitora alfa-gobe), Eli Lilly’s once-weekly basal insulin for adults with type 2 diabetes. The insulin is used alongside diet and exercise to improve glycemic control and is administered once weekly on the same day each week. Onswik is now the second once-weekly basal insulin approved in the United States, following Novo Nordisk’s Awiqli earlier in 2026.

The approval was supported by Lilly’s Phase 3 QWINT clinical trial program, which included more than 3,400 adults with type 2 diabetes. Across four studies involving both insulin-naive and insulin-experienced participants, once-weekly efsitora produced A1C reductions comparable with once-daily insulin glargine or insulin degludec.

A major practical difference is injection frequency. Lilly estimates that once-weekly dosing could reduce basal insulin injections from about 365 per year to 52, eliminating more than 300 injections annually compared with once-daily basal insulin.

Onswik will be offered in two high-concentration KwikPen formulations, U-500 and U-1,000, and Lilly says the product will become available in the U.S. in the coming months.

The drug is not recommended for people with type 1 diabetes because of an increased risk of severe hypoglycemia. Common adverse reactions include hypoglycemia, allergic reactions, injection-site reactions, lipodystrophy, itching, rash, swelling, and weight gain.

Why This Matters

Once-weekly basal insulin could make insulin therapy less burdensome for some adults with type 2 diabetes by replacing a daily basal injection with one scheduled injection each week.

Onswik also marks an important change in the U.S. insulin landscape. It is the second once-weekly basal insulin approved for adults with type 2 diabetes, following Novo Nordisk’s Awiqli in March 2026. Awiqli became available in U.S. pharmacies in August, meaning weekly basal insulin is moving from a new concept to an emerging treatment category with more than one option.

Weekly dosing may be useful for people who find daily insulin injections difficult to maintain consistently, including some people who rely on caregivers for insulin administration. But fewer injections do not necessarily make insulin management simple. Weekly insulins have their own starting-dose, titration, missed-dose, and safety considerations, making patient education especially important.

The QWINT clinical trial program found that once-weekly Onswik achieved A1C reductions comparable with once-daily basal insulins. With both Awiqli and Onswik now FDA approved, attention will increasingly shift from clinical trial efficacy to how once-weekly basal insulins perform in everyday care, including questions of access, insurance coverage, dosing, adherence, and individual preference.

More About Awiqli

JCS/T2D: "Awiqli, the First Once-Weekly Basal Insulin, Now Available in the US"
JCS/T2D: "FDA Approves Awiqli as First Once-Weekly Basal Insulin for Type 2 Diabetes"

Sources

FDA: "FDA Approves Once-Weekly Insulin for Type 2 Diabetes Mellitus"
Lilly: "U.S. Food and Drug Administration (FDA) approves Lilly's Onswik™ (insulin efsitora alfa-gobe), a once-weekly basal insulin injection treatment for adults living with type 2 diabetes"
Diabetes Dialogue: "Weekly Insulin Efsitora Alfa Gets FDA Approval for Type 2 Diabetes" (Article)
Diabetes Dialogue: "FDA Approves Onswik, A Weekly Basal Insulin" (Video)
Medscape: "FDA Approves Efsitora Once-Weekly Basal Insulin Injection"
Fierce Pharma: "Lilly brings more heat to Novo with FDA nod for once-weekly insulin Onswik"