A This is a single-center, randomized, double-blind, placebo-controlled, dose-escalation Phase I clinical trial. It aims to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of a single administration of JMT206 Injection in healthy participants.

Inclusion Criteria:

1. Aged 18 to 60 years (inclusive) at screening, male or female.
2. Body weight ≥ 50.0 kg for males and ≥ 45.0 kg for females at screening, with a body mass index (BMI) ranging from 19.0 to 28.0 kg/m^2 (inclusive).
3. Body weight change < 5% within 3 months prior to screening, and consistent diet and exercise habits maintained from screening until prior to dosing (based on participants's statement). Calculation formula: (Body weight at 12 weeks prior to screening - Body weight at screening) / Body weight at screening * 100%.
4. Results of examinations such as vital signs, physical examination, 12-lead electrocardiogram (ECG), posteroanterior chest X-ray, B-ultrasound (abdomen, urinary system, gynecological (female only)), and clinical laboratory tests (including but not limited to complete blood count, urinalysis, blood biochemistry, coagulation function, serum virology, thyroid function, tumor marker tests, etc.) are within normal ranges or assessed by the investigator as abnormal but not clinically significant.
5. Both the participant and their partner agree to use a contraceptive method with a ≤1% annual failure rate or maintain abstinence from signing the informed consent form until 6 months after the last dose. Male participants have no plan to donate sperm from signing the informed consent until 6 months after the last dose; female participants have no plan to donate ova from signing the informed consent until 6 months after the last dose.
6. Able to read, understand, and provide written informed consent for the study-related information. Have a full understanding of the trial content, procedures, and potential adverse reactions. Voluntarily sign the informed consent form prior to the trial and ensure personal participation in all study procedures.

Exclusion Criteria:

1. Participants with a history of hypersensitivity or known/suspected allergy to JMT206 or any component of the investigational product.
2. Participants with a history of risk factors for Torsades de pointes (TdP) (e.g., heart failure/cardiomyopathy or family history of long QT syndrome), uncorrected hypokalemia or hypomagnesemia (one retest allowed per investigator's judgment), or currently taking concomitant medications known to prolong the QT/QTc interval.
3. Participants with a current clinically significant illness, or history of chronic or severe diseases. This includes, but is not limited to, diseases of the circulatory, lymphatic, respiratory, endocrine, urinary, digestive, nervous or psychiatric systems, infections, malignancies, severe trauma, or any other condition that the investigator considers grounds for exclusion or may interfere with the interpretation of the study results.
4. Participants with known concomitant conditions that affect skeletal muscle protein, or use of any form of skeletal muscle anabolic drugs or supplements within 3 months prior to screening.
5. Participants with a history of gastrointestinal surgery resulting in malabsorption, or long-term use of drugs that directly affect gastrointestinal motility. Examples include: prior bariatric surgery or procedures (e.g., gastric banding); use of medications or products deemed by the investigator to cause weight changes and affect weight assessment within 3 months prior to dosing; or intention to use weight-loss medications during the study period.
6. Use of any prescription drugs, over-the-counter medications, or Chinese herbal medicines within 4 weeks prior to screening.
7. Average alcohol consumption exceeding 14 units per week within 3 months prior to screening (1 unit = 285 mL of beer, 25 mL of spirits, or 150 mL of wine), or consumption of any alcohol-containing products within 48 hours prior to investigational product administration, or a positive alcohol breath test, or inability to abstain from alcohol during the trial.
8. Smoking ≥5 cigarettes per day within 6 months prior to screening, or smoking within 48 hours prior to investigational product administration, or inability to discontinue use of any tobacco products during the trial.
9. Habitual consumption within 3 months prior to screening, or ingestion within 72 hours prior to investigational product administration, of pitaya (dragon fruit), mango, pomelo, carambola (star fruit), or foods/beverages prepared from them; or excessive intake of foods/beverages containing xanthine or caffeine, or other items known to affect drug absorption, distribution, metabolism, or excretion. Examples include: coffee (>1100 mL/day), tea (>2200 mL/day), cola (>2200 mL/day), energy drinks (>1100 mL/day), chocolate (>510 g/day).
10. History of drug abuse within 6 months prior to screening, or a positive drug abuse screening test.
11. Transfusion, blood loss, or blood donation exceeding 400 mL within 3 months prior to dosing (excluding menstrual blood loss in females), and/or platelet donation within 2 weeks prior to dosing.
12. History of needle or blood phobia (vasovagal syncope related to needles or blood), difficult blood sampling, or intolerance to venipuncture.
13. Participants with specific dietary requirements who cannot comply with the standardized diet and schedule.
14. Female participants who are pregnant, lactating, or have a positive pregnancy test at screening.
15. Participation in any drug or medical device clinical trial within 3 months prior to screening, or planning to participate in another clinical trial during the study period.
16. Any other condition or circumstance that, in the investigator's judgment, renders the participant unsuitable for participation in the study