Could a daily cocoa drink help keep blood vessels young?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Male participants aged 30 to 75 years. * Able and willing to provide written informed consent. * Generally healthy, as determined by medical history and screening assessments. * Willing and able to comply with all study procedures, including blood collection, daily study-product intake, and required study visits. * Willing to consume the assigned cocoa flavanol supplement or low-flavanol control product once daily for the duration of the study. * Willing to provide peripheral blood samples at baseline and at the end of the intervention. * Willing to maintain generally stable dietary, exercise, sleep, medication, and supplement habits during the study. * Willing to refrain from initiating new supplements, restrictive diets, fasting regimens, or major exercise programs during the study. * Not currently taking medications or supplements known to substantially affect vascular function, nitric oxide pathways, inflammation, oxidative stress, or coagulation, unless approved by the investigator. Exclusion Criteria: * Female biological sex. * Younger than 30 years or older than 75 years. * Known cardiovascular, metabolic, renal, hepatic, inflammatory, or autoimmune disease, including coronary artery disease, diabetes mellitus, chronic kidney disease, chronic liver disease, rheumatoid arthritis, or another clinically significant inflammatory disorder. * Hypertension requiring prescription medication. * Active infection, acute illness, or other clinically significant medical condition at screening or baseline. * Current use of medications or supplements that may substantially affect vascular function, inflammatory biomarkers, nitric oxide pathways, oxidative stress, or coagulation, including chronic nonsteroidal anti-inflammatory drugs, systemic corticosteroids, anticoagulants, antiplatelet drugs, prescription immunomodulatory agents, phosphodiesterase-5 inhibitors, or high-dose antioxidant supplements, unless approved by the investigator. * Known allergy, hypersensitivity, or intolerance to cocoa, chocolate, cocoa flavanols, or any ingredient in either study product. * Gastrointestinal disease or condition that may interfere with digestion or absorption of the study product, including celiac disease, inflammatory bowel disease, active gastritis, or a clinically significant malabsorption disorder. * Current smoking or vaping of nicotine or cannabis products. * Major psychiatric illness, cognitive impairment, or another condition that may interfere with informed consent, adherence, or completion of study procedures. * Alcohol or drug abuse within the previous 12 months that, in the investigator's judgment, may affect participant safety or study adherence. * Participation in another interventional clinical study within 30 days before screening. * Plans to begin a new medication, supplement, restrictive diet, fasting regimen, or major exercise program during the study period. * Any condition or circumstance that, in the investigator's judgment, would increase participant risk, interfere with study procedures, compromise adherence, or affect interpretation of the study results.