Spermidine

An autophagy-inducing polyamine with intriguing observational and early-trial cognitive signals.

Overall grade: Grade C
Last revised: Jul 10, 2026; 2
graded outcomes: 0
references listed

A structured monograph in Prometheus's bundled library. Its grades are the monograph's own reading of the evidence, not a peer-reviewed review.

2 at grade C — 2 graded rows

What is known

Each outcome with its grade (how strong the evidence is, A to D), the size of the effect where the entry records one, and how often studies agree.

Outcome	Grade	Effect size	Agreement
Memory (at-risk older adults)Early trials	Evidence grade C	Small	mixed
Mortality (observational)Association only	Evidence grade C	Unclear	mixed

Memory (at-risk older adults)Evidence grade C
Early trials
Smallmixed
Mortality (observational)Evidence grade C
Association only
Unclearmixed

What is uncertain

Read off the same rows as above. Nothing here is added that the entry does not itself record.

Thin evidence: Memory (at-risk older adults) (grade C); Mortality (observational) (grade C).

The evidence in words

What it is

Spermidine is a polyamine found in wheat germ and fermented foods that induces autophagy, the cell's recycling process.

How it works

By promoting autophagy it may support cellular housekeeping linked to aging and cognition.

What the evidence shows

Observational cohorts link higher dietary spermidine to lower mortality, and small trials suggest modest memory benefits in at-risk older adults. Promising and mechanistically appealing, but early. Safe as a food component.

How to use it

1–6 mg/day from wheat-germ extract or supplements.

Safety & interactions

Food-derived, appears safe.

Bottom line

One of the more interesting longevity candidates on autophagy grounds, with early cognitive signals. Low-risk to trial; evidence is still building.

How it is used

As the entry records it, from the studies it summarises. Not a recommendation for you — doses that suit a trial population may not suit you.

Standard: 1–6 mg/day.

Entries that share this one's tags or conditions.

Spermidine for Memory (at-risk older adults)Evidence grade C — Early trialsEvidence grade C
Spermidine for Mortality (observational)Evidence grade C — Association onlyEvidence grade C
Spermidine: dosage and how to take it1–6 mg/day.Evidence grade C
Spermidine: side effects, safety & interactionsFood-derived, appears safe.Evidence grade C

Sources

This entry lists no references of its own.

Last revised Jul 10, 2026. A grade is this entry's reading of the evidence, not medical advice.