This study is testing a new drug called ZT-01, which might help people with type 1 diabetes (T1D) who have low blood sugar, or hypoglycemia, at night. Hypoglycemia is when blood sugar drops too low. ZT-01 helps increase a hormone named glucagon during these times, potentially preventing these low sugar episodes. Participants will try ZT-01 and a placebo (a look-alike without the active ingredient) over two 4-week periods. They'll inject the study drug before bed while using a special device called a continuous glucose monitor (CGM) to track blood sugar levels. The study lasts about 16 weeks and includes six visits and two phone calls. Participants will have their blood and urine tested and might need to stay overnight for additional tests.

• Study duration: about 16 weeks with 6 visits and 2 calls.
• Participants will use a CGM and inject the study drug themselves.
• Some may stay overnight at the study site for extra testing.