Emerging evidence identifies vascular aging independently predicting cardiovascular events, yet effective clinical interventions remain lacking. Nicotinamide adenine dinucleotide (NAD+) is an essential cofactor whose levels decline with age, and preclinical studies suggest that boosting NAD+ can improve vascular function and structure. Preliminary clinical studies in healthy older adults indicate that supplementation with NAD+ precursors, such as nicotinamide riboside(NR) or nicotinamide mononucleotide (NMN), can reduce arterial stiffness as measured by pulse wave velocity (PWV). However, whether NAD+ supplementation can improve vascular endothelial function and exert anti-stiffening effects in patients who have already developed measurable arterial stiffness remains unknown. Based on this evidence, the investigator hypothesize that the Coenzyme I for Injection will reverse vascular aging in older adults with established arterial stiffening.

Inclusion Criteria:

1. Ages 40-70 years;
2. cf-PWV was abnormally elevated and above the upper limit of its age-and blood-pressure matched reference range;
3. Systolic Blood Pressure < 160 mmHg and ≥ 140 mmHg or Diastolic BP < 100 mmHg ≥ 90mmHg;
4. Signed informed consent.

Exclusion Criteria:

1. Consumption of foods or medications containing high levels of NAD+, NR, NAM, NMN, or niacin-related components (including Vitamin B3 and natural health products) within 3 months prior to screening；
2. History of major cardiovascular or cerebrovascular events, including myocardial infarction, angina, stroke, or hospitalization for arterial revascularization；
3. Systolic blood pressure ≥ 160 mmHg and/or diastolic blood pressure ≥ 100 mmHg；
4. Diagnosis of malignant tumor；
5. Known allergy or history of severe adverse reactions to Coenzyme I injection or any of its components；
6. History of severe allergies or infusion reactions；
7. Women who are pregnant, breastfeeding, or planning pregnancy；
8. Severe hepatic or renal dysfunction: ALT or AST > 5 times the upper limit of normal; glomerular filtration rate ≤ 30 mL/min/1.73 m²；
9. Concurrent participation in another clinical trial without completion of the follow-up period；
10. Other conditions deemed by the investigator as unsuitable for inclusion, such as psychiatric or psychological disorders.