Acute and Chronic Effects of Oral Ketones in Subjects With HFrEF and Diabetes

Inclusion Criteria: * Subjects must be on a stable dose of guideline-directed medications for Heart Failure (HF). * Patients will have an established diagnosis of HF before the screening visit, documented by an acceptable imaging modality in the last 6 months. * Age = 18-80 y * Body Mass Index (BMI) =23-38 kg/m2 * Glycated hemoglobin (HbA1c) = 6.0-10.0% * Blood Pressure (BP) \< 145/85 mmHg * Estimated Glomerular Filtration Rate (eGFR) \> 30 ml/min•1.73 m2 * For women of child-bearing age (WOCBA) willingness to use contraception, if applicable. Exclusion Criteria: * Patients treated with Sodium-Glucose Transport Protein (SGLT2i's) or medications that may impair heart function or acutely worsen glycemic control will be excluded. * Pregnancy, lactation, or plans to become pregnant. A negative pregnancy test will be performed before each Magnetic resonance imaging (MRI) study to assess current status. * Allergy/sensitivity to study drugs or their ingredients. * Current drug or alcohol use or dependence that, in the opinion of the site investigator, would interfere with adherence to study requirements. * Inability or unwillingness of individual or legal guardian/representative to give written informed consent. * Subjects with a history of cancer (except basal or squamous cell cancer that has been resolved/remission for 5 years) * Cardiovascular event within the last 3 months * Major organ or metabolic diseases, or physical limitations that will not allow the subject to complete the study.