Peptides, particularly certain bioactive peptides derived from food proteins and endogenous peptides, have been investigated for their potential benefits in supporting cardiovascular health, including conditions involving "heart weakness" (which may refer to heart failure or reduced cardiac function). Scientific studies have shown that specific peptides can exert antihypertensive, antioxidant, anti-inflammatory, and lipid-lowering effects, all of which may indirectly benefit heart function. For instance, peptides that inhibit angiotensin-converting enzyme (ACE) can help lower blood pressure, reducing strain on the heart. Additionally, clinical studies on peptides like B-type natriuretic peptide (BNP) and synthetic analogs (e.g., nesiritide) have demonstrated hemodynamic improvements in patients with acute decompensated heart failure.

However, while there is a growing body of preclinical and some clinical evidence supporting the cardiovascular benefits of specific peptides, the overall quality and quantity of human clinical trials remain limited. The use of peptide-based drugs in heart failure is established in acute settings, but the use of dietary or supplemental peptides for chronic heart weakness is still under investigation and not yet widely validated by large-scale randomized controlled trials. Therefore, while there is scientific rationale and preliminary evidence for the use of certain peptides in supporting heart function, the strength of evidence is moderate, justifying a rating of 3 out of 5.