· 3 min read · LONGEVITY LEAK
POLYCAD Trial: Spermidine Supplementation in Coronary Artery Disease — Design and Interim Context
The POLYCAD trial is testing 24 mg/day spermidine in 187 older adults with coronary artery disease for 48 weeks. Trial completion is expected August 2026 — no efficacy results exist yet. Prior cohort data from Eisenberg et al. 2016 provides the rationale.
Clinical Brief
- Source
- Peer-reviewed Clinical Study
- Published
- Primary Topic
- spermidine
- Reading Time
- 3 min read
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See full scoring guideThe POLYCAD (POLYamine CArdiovascular Disease) trial is an ongoing randomized controlled trial testing spermidine supplementation in older adults with established coronary artery disease (CAD). The trial design was published in Trials (2025). Completion is expected in August 2026 — no efficacy results are available. Claims that spermidine reduces cardiovascular risk by specific percentages in this population are not supported by current evidence; the trial is still underway.
What Is Spermidine?
Spermidine is a naturally occurring polyamine found in all living cells and in dietary sources including wheat germ, aged cheese, soy products, and mushrooms. Intracellular spermidine levels decline with age. Spermidine activates autophagy — the cellular process by which damaged proteins and organelles are degraded and recycled — through a mechanism involving the acetyltransferase EP300. Autophagy induction is one of the proposed mechanisms by which caloric restriction extends lifespan.
Prior Cohort Evidence (Rationale for the Trial)
Eisenberg et al. (2016), Nature Medicine: The primary epidemiological rationale for POLYCAD comes from a prospective cohort study in 829 Italians aged 45–84. Higher dietary spermidine intake was associated with lower overall and cardiovascular mortality over a 20-year follow-up period. This dose-response association remained after adjustment for confounders. Separately, spermidine supplementation extended lifespan in multiple model organisms (yeast, flies, worms, mice) and reduced cardiac aging markers in mice.
Observational cohort data cannot establish causation — dietary spermidine intake may be a marker of a healthy dietary pattern overall (wheat germ, aged cheese, fresh produce) rather than an independent causal factor. Randomized trial evidence is needed to determine whether supplementation produces the cardiovascular benefit suggested by cohort data.
POLYCAD Trial Design
Population: 187 participants aged 65 years or older with confirmed coronary artery disease (prior MI, angiographically confirmed CAD, or history of coronary revascularization)
Intervention: Wheat germ extract providing 24 mg/day spermidine vs. placebo, oral, for 48 weeks
Primary endpoints: Cardiac function markers (echocardiographic measures), physical performance, and inflammatory biomarkers
Secondary endpoints: Muscle mass (sarcopenia markers), quality of life, cognitive function screening, and safety
Expected completion: August 2026
The trial is powered for biomarker endpoints, not hard cardiovascular event outcomes (MI, cardiovascular death). A biomarker-endpoint trial cannot by itself establish that spermidine reduces cardiovascular events.
Mechanism: How Spermidine May Help the Heart
In preclinical models, spermidine supplementation:
- Induced cardiac autophagy, reducing accumulation of damaged mitochondria and protein aggregates
- Reduced mitochondrial ROS production in cardiomyocytes
- Improved diastolic function in aged mice
- Reduced inflammation markers (IL-6, TNF-alpha) in cardiac tissue
Whether these mechanisms operate at the doses achievable through supplementation in humans — and whether they translate to meaningful clinical outcomes — is what POLYCAD is designed to begin answering.
What Remains Uncertain
POLYCAD results are not available. The trial will answer whether 24 mg/day spermidine improves cardiac biomarkers in older adults with CAD, but will not be powered to detect cardiovascular event reduction. Whether the observed cohort association between dietary spermidine and cardiovascular mortality reflects spermidine specifically or overall diet quality is unresolved. Optimal dose, duration, and population (healthy vs. established CAD) for supplementation are unknown. Long-term safety of concentrated spermidine supplementation has not been evaluated in large populations.
Related Topics
Sources
- POLYCAD trial design (2025). Trials. https://link.springer.com/article/10.1186/s13063-025-09176-z
- Eisenberg T et al. (2016). Cardioprotection and lifespan extension by the natural polyamine spermidine. Nature Medicine. https://www.nature.com/articles/nm.4222
Source Documentation
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