Luna Diabetes has raised $23.6 million in Series A funding, led by Vensana Capital, to advance development of its nighttime-only patch pump. The San Diego startup is building what it calls the world’s smallest automated insulin delivery (AID) device, designed to work alongside insulin pens rather than replace them.

Here is how it works: users continue with their usual insulin pen injections during the day and apply the Luna patch pump at night. Guided by continuous glucose monitor (CGM) data, the pump delivers micro-doses of rapid-acting insulin during sleep, targeting the hours when many of the benefits from automation typically occur.

Somewhere between 30-40% of people with type 1 diabetes in the US continue to use MDI over insulin pumps (source). That highlights just how large the population is that could benefit from add-on automation tools. For those not ready or interested in wearing a pump full time, Luna could provide a middle ground and cushion for bedtime hyperglycemia.

The Series A funding comes as Luna advances through pivotal trials. The company launched its study last fall, and funding will support regulatory submissions, expanded clinical work, and manufacturing buildout. FDA clearance is still ahead, but the company now has resources to push toward market.

Competition in patch pumps is heating up. Insulet leads today, while Tandem, Medtronic, and Beta Bionics prepare its own tubeless systems. Luna’s differentiation is its nighttime-only focus, which could reduce the pressure to move toward traditional AID pumps while also strengthening the broader MDI and smart pen ecosystem. For people with diabetes, that could mean better overnight control, fewer alarms, and smoother mornings, all without changing daytime routines.

I’ve interviewed CEO John Sjolund about Luna’s design and vision. Sjolund, who has lived with type 1 diabetes since childhood, previously co-founded Timesulin and has built a team with veterans from Bigfoot Biomedical and Beta Bionics. Check out our full podcast interview with Sjolund below for a deeper dive on how Luna works and how it hopes to change the game for people with diabetes.

Disclaimer: Diabetech content is not medical advice—it’s for educational purposes only. Always consult with a physician before making changes to your healthcare.