A Phase 1 Study to Investigate Safety, Tolerability, and Pharmacokinetics of CK-0045 in Healthy Participants and Otherwise Healthy Participants With Obesity

Inclusion Criteria: * For non-vasectomized men with partners who are women of child bearing potential (WOCBP) and for WOCBP, highly effective contraception for 3 months. * For all female participants: a negative serum (β-hCG) pregnancy test at screening and a negative urine pregnancy test on Day -1. * In the opinion of the investigator, healthy based on medical history, physical and neurological examination, vital signs, and ECG, and clinical chemistry, hematology, coagulation, and urinalysis. * A body weight in the range of 50 to 100 kg and a body mass index (BMI) of 18.5 to 27.0 kg/m2, inclusive, at screening for the SAD part and a BMI of 30.0 to 39.9 kg/m2, inclusive, at screening for the MAD part. * A systolic blood pressure of ≥91 and ≤140 mmHg (SAD) / ≤145 mmHg (MAD) , a diastolic blood pressure of ≥51 and ≤80 mmHg (SAD) / ≤90 mmHg (MAD), and a pulse rate of ≥45 and ≤100 bpm at screening and Day 1 predose. * Negative COVID-19 test (PCR) and no clinical symptoms of corona on Day -1. * Signed informed consent form. * Willing to adhere to the prohibitions and restrictions specified in the protocol. Exclusion Criteria: * Currently have or have a history of any clinically significant medical illness or medical disorders the investigator considers should exclude the participant. * Have one or more clinical laboratory test values outside the normal range at screening or on Day -1 (exceptions apply to MAD for fasting glucose, triglycerides, total cholesterol and liver enzymes). * Has a QTcF interval \>430 ms at screening or Day 1 predose for the SAD part or has a QTcF interval \>450 ms (for male participants) or \>470 ms (for female participants) at screening or Day 1 predose for the MAD part. * Have a clinically significant or chronic infection or diagnosed latent infection. * Significant acute illness within 7 days prior to the (first) study drug administration or have had a major illness or hospitalization within 1 month prior to the (first) study drug administration. * Any history of clinically relevant skin diseases including but not limited to: Psoriasis, vitiligo, atopic dermatitis, eczema. * History of any malignancy. * Tattoos present on place of injection site. * Major or traumatic surgery within 6 months of screening. * Any participant who plans to undergo elective surgery within 4 weeks prior to the (first) study drug administration and through the end of the study. * Positive serology test for HIV type 1 and 2 antibodies, hepatitis B surface antigen (HBsAg), or hepatitis C virus (HCV) antibodies at screening. * Recent history (within 6 months from screening) of alcohol or drug abuse. * Active smoker and/or has used nicotine or nicotine-containing products (including e cigarettes or the equivalent of e-cigarettes) within the past 6 months of the (first) study drug administration. * A positive urine toxicology screen at screening or Day -1 for substances of abuse. * Have a positive alcohol breath test at screening or Day -1. * Consumes, on average, more than approximately 500 mg/day of caffeine at screening for the SAD part or consumes, on average, more than approximately 700 mg/day of caffeine at screening for the MAD part. * Donated blood within 90 days prior to (first) study drug administration. * Trains/exercises intensively, e.g., for a marathon or triathlon, or at a competitive level. * Have a history of active drug and/or food allergy or other active allergic disease requiring the constant use of medications, or a history of severe allergic reaction, angioedema or anaphylaxis at screening. * Received any experimental therapy or new investigational agent within 30 days or 5 half-lives (whichever is longer) of the (first) study drug administration. * Treatment with over-the-counter medications, and herbal medication within 14 days or prescription medications within 14 days or 5 half-lives (whichever is longer) prior to (first) study drug administration and through the end of the study, unless approved by the investigator.