Consuming cocoa rich in flavan-3-ols (particularly epicatechin [EC]) may reduce vascular stiffness and blood pressure (BP) and improve serum lipid profiles. Because interventional studies on pure EC exhibited inconclusive results, the role of other cocoa ingredients such as methylxanthines (MX) on vascular health was assumed. This study aimed to systematically compare the effects of flavanol-rich cocoa and its major components EC and MX on vascular function and serum lipid levels. In a randomized controlled trial (RCT), 75 healthy young adults ingested capsules containing either (i) flavanol-rich cocoa powder, (ii) EC, (iii) MX, (iv) EC + MX, or (v) placebo (n = 15 per group) daily for 4 weeks. Capsules provided equal amounts of EC and/or MX as the cocoa capsules. Pulse wave velocity (PWV), BP, endothelin-1, and lipids were investigated before and after intervention. No group-specific statistically significant differences in aortic PWV (p = 0.410) or any other parameters (p ≥ 0.05) were observed between before and after the intervention. Daily intake of neither flavanol-rich cocoa nor pure cocoa ingredients influenced vascular function and lipid profiles in healthy adults. Consequently, RCTs involving subjects with increased cardiometabolic risk may clarify the effects of EC and MX as cocoa components on cardiovascular health parameters. Trial Registration: URL: https://drks.de/search/en/trial. Unique identifier: DRKS00022056.