Clinical Research Directory

Inclusion Criteria: * Aged 30-80 years old * Have type 2 diabetes * HbA1c between 5.7 - 12.0% * On a stable dose of metformin, DPP-IV inhibitors, SGLT2 inhibitors, sulfonylureas, and/or GLP-1 receptor agonists for at least 6 weeks, or taking no diabetes medications * Wake up at a regular time between 5-9 am Exclusion Criteria: * On insulin or diabetes medication other than metformin, DPP-IV inhibitors, SGLT2 inhibitors, sulfonylureas, and/or GLP-1 receptor agonists * Have type 1 diabetes or was diagnosed with diabetes before age 18 * Moderate or severe retinopathy or other medical condition that may affect the ability to safely receive bright light therapy * A history of severe hypoglycemia * Change in the dosage of a chronic medication within the past month (need to wait at least 1 month prior to baseline visit) * Have a clinically significant laboratory abnormality (e.g., abnormal hemoglobin levels) * Severe gastrointestinal disease, major gastrointestinal surgery, or active gallstone disease * Cardiovascular, renal, cardiac, liver, lung, adrenal, or nervous system disease that is unstable or may compromise study validity * Evidence of cancer (other than non-melanoma skin cancer) within the last 5 years * Pregnant or breastfeeding * Current diagnosis of a major psychiatric condition that would impair study participation * Diagnosed sleep disorder or circadian disorder that is not stabilized (sleep apnea is allowed). Those with narcolepsy will not be included. * Major changes in health or medical history in the last 3 months that could affect data validity per judgement of the study physician * Spend an average of more than 1.5 hours/day outdoors * Perform overnight shift work more than 1 day/week on average * Regularly eat within a less than a 10-hour period daily * Regularly finish eating dinner before 6:30 pm * Lost or gained more than 8 lbs within the last 2 months and weight needs to be stable for a minimum of 4 weeks before baseline testing * Traveled more than two times zones away in the two months prior to enrolling in the trial or will travel more than two time zones away during the 16-week study