Study to Demonstrate Pharmacokinetic and Pharmacodynamic Similarity Between NKF-INS(L), US-Humalog®, and EU-Humalog®

1. Signed and dated informed consent obtained before any trial-related activities. Trial-related activities are any procedures that would not have been done during normal management of the participant
2. Healthy male participants
3. Age between 18 and 50 years, both inclusive
4. Body Mass Index between 18.5 and 29.0 kg/m2, both inclusive
5. Body weight ≥ 50 kg
6. Fasting glucose concentration ≤ 5.5 mmol/L at screening
7. Considered generally healthy upon completion of medical history, physical examination, vital signs, electrocardiogram (ECG), and analysis of laboratory safety variables, as judged by the Investigator
8. Willing and able to comply with scheduled visits, treatment plan, clinical laboratory tests, and other study procedures including lifestyle considerations.
9. Participants must agree to use condoms during sexual intercourse. Additionally, female partners of male participants should use highly effective contraception. All contraceptive measures apply from screening until 90 days after study treatment. Male participants must refrain from donating or banking sperm for 90 days after administration of study treatment.
10. Have competence in speaking, writing, and comprehending the local language(s) where the study is conducted.

Exclusion Criteria:

1. Positive for human insulin antibodies at Screening
2. Are currently enrolled in or have discontinued within 3 months or 5 half-lives (whichever is longer) of any investigational drug or device or are concurrently enrolled in any other type of medical research study and judged not to be scientifically or medically compatible with this study.
3. Have known allergies to insulin, its excipients, or related drugs or have history of relevant allergic reactions of any origin, or any specific investigational product safety concern
4. History of diabetes mellitus; episodes of hypoglycemia in the anamnesis; any history of insulin use for treatment purposes.
5. Have clinically relevant history of or current cardiovascular, respiratory, hepatic, renal, gastrointestinal, endocrine, hematological, or neurological disorders capable of significantly altering the absorption, metabolism, or elimination of drugs; of constituting a risk when taking the study drug; or of interfering with the interpretation of data.
6. Increased risk of thrombosis, e.g., individuals with a history of deep leg vein thrombosis or family history of deep leg vein thrombosis, as judged by the Investigator.
7. Clinically significant abnormal ECG at screening.
8. Glycemia level ≥140 mg/dL 2 hours after the glucose load.
9. Evidence of psychiatric disorder, antagonistic personality, poor motivation, emotional or intellectual problems likely to limit the validity of consent to participate in the study or limit the ability to comply with protocol requirements.
10. Positive urine drug test at screening and/or evidence of current use of known drugs of abuse or have a history of use within the past year.
11. Show evidence of an acute infection with fever or infectious disease at the time of enrollment.
12. Show evidence of human immunodeficiency virus (HIV) infection and/or positive human HIV antibodies at screening.
13. Have positive test results for hepatitis B surface antigen (HBsAg), immunoglobulin M (IgM) antibody to hepatitis B core antigen (anti-HBc), or hepatitis C virus (HCV) antibodies at screening.
14. Intend to use over-the-counter medication within 7 days or prescription medication within 14 days prior to dosing (apart from vitamin/mineral supplements, occasional paracetamol, thyroid replacement).
15. Have donated blood or had a blood loss of 500 mL 3 months prior to study enrollment.
16. Have an average weekly alcohol intake that exceeds 21 units per week or is unwilling to stop alcohol consumption from 48 hours prior to each dosing until being discharged from the Clinical Research Unit (CRU).
17. Employees or close relatives of the contract research organization, the sponsor, 3rd party vendors or affiliates of the above-mentioned parties
18. Have inadequate venous access.
19. Vulnerable participants, e.g., persons in detention.