Spermidine enhances autophagy through inhibition of the acetyltransferase EP300, thereby promoting histone hypoacetylation and upregulation of autophagy-related genes, particularly in post-mitochondrial compartments. This mechanism targets the cellular senescence and proteostasis hallmarks of aging by facilitating clearance of damaged organelles and protein aggregates. In preclinical models, spermidine supplementation extends lifespan by 10-25% and improves age-related phenotypes including cardiac function and metabolic health. Limited human data from prospective cohort studies suggest higher dietary spermidine intake correlates with reduced cardiovascular mortality and improved cardiometabolic markers, though randomized controlled trials examining direct lifespan or healthspan effects in aging populations remain sparse.
Spermidine is a polyamine sold as a dietary supplement and is not FDA-approved as a drug for any indication.
Phase II data has examined cognitive endpoints (Madeo lab). Geroevidence's profile is currently under editorial review pending additional published human evidence.
Spermidine is studied as an autophagy-inducing compound, mechanistically related to research on rapamycin and caloric restriction, though with a distinct and less mature human evidence base.
Spermidine has a generally favorable safety profile in available human studies to date; long-term and high-dose safety data remain limited.
Both are studied as autophagy inducers, though through different pathways — rapamycin via direct mTORC1 inhibition, spermidine via polyamine-related mechanisms. See the rapamycin profile for comparison.