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Spermidine UK: Evidence & User Reports (Benefit Unproven)

supplement

Spermidine

Also known as Spermidine (wheat germ extract)

Polyamine found in wheat germ, soybeans and aged cheese, promoted as an autophagy ('cell clean-up') booster because it extends lifespan in animals. In humans even the biochemical step is unconfirmed: placebo-controlled trials at 15 mg and 40 mg a day did not raise blood spermidine, and the largest trial (SmartAge, 12 months, 100 older adults) found no memory benefit.

2linked conditions

0linked studies

On this pageWhat studies found Evidence Availability Outcomes & conditions →

Evidence

What the research actually shows

We link to relevant studies and leave interpretation to you and your healthcare professional.

What studies found

The headline results, condition by condition

The large figures are what the studies reported for each thing they measured. Open a card for every result.

Cognitive Function

3 of 6 results reported a benefit

4 randomised trials, 100 people

Memory performanceNo clear difference0.03 lower, unit not reported1 randomised trial2 of 3 results reported a benefit2022 study ↗
Overall thinking skillsRose by 2.23 points compared with the start of the studyon the MMSE scale1 randomised trial, compared with the start of the study2021 study ↗
Verbal fluency and alertness

Outcomes & conditions

Why people look into Spermidine — and what they report

Associated conditions and community-reported outcomes, wrapped together on one page. Aggregates appear only once enough reports arrive.

Outcomes & conditions →

Important: This page reflects observational, aggregate-only community reporting and independent published research. It is not medical advice, and it does not claim any compound treats, cures, or is effective for any condition. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or treatment.

Availability

Where to get Spermidine (UK)

How this compound is sold in the UK, and where our readers typically find it.

Retailer search links — we may earn commission on purchases at no cost to you. Commission never affects our evidence ratings.

Search Spermidine on Amazon UK →Search Spermidine on Holland & Barrett →Search Spermidine on iHerb →

What trials found, in numbers

Summaries of published trial results for this compound, grouped by condition. In these tables every number is exactly as the researchers published it. The headline figures above show a simple average where several studies measured the same thing in the same unit, and say so; nothing else is calculated or converted.

How to read this table

Benefit: What the trial saw happen: whether the measured outcome moved in the helpful direction in that one study (the tag on each row: “Benefit seen”, “No clear benefit”, “Possible harm” or “Unclear”). It is a study result — not advice, and not a promise it will work for you.
Evidence: How strong the research behind that result is. A meta-analysis pools many studies (strongest); a systematic review collates them; an RCT tests against a control (placebo); observational studies only watch — they can suggest, not prove.
Effect size: How large the measured change was, exactly as the researchers published it. “No number reported” means the abstract gave no effect size — we never invent one.

In short: benefit is what was observed; evidence is how much you should trust the observation. A “Benefit seen” tag on a weak study counts for far less than the same tag on a meta-analysis.

Cognitive Function (10 outcomes)

Outcome measured	What trials found	Effect size	People studied	Duration	Type of evidence	Study
Mnemonic discrimination performance	Spermidine-rich dietary supplement extracted from wheat germ (0.9 mg spermidine/d) did not significantly improve Mnemonic discrimination performance (-0.03; 95% CI, -0.11 to 0.05; P = .47) compared with placebo in 100 (12 months). (95% CI, -0.11 to 0.05; P = .47)No clear benefit	-0.03	100	12 months	RCT · 2022	PMID 35616942
MMSE score in mild dementia (higher-dose group)	Spermidine (higher dose) improved MMSE score in mild dementia (higher-dose group) (2.23 points; p = 0.026) compared with lower spermidine intake in 85. (p = 0.026)Benefit seen	2.23 points	85	—	RCT · 2021	PMID 33211152
Phonematic fluency in mild dementia (higher-dose group)	Spermidine (higher dose) did not significantly improve Phonematic fluency in mild dementia (higher-dose group) (1.99; p = 0.47) compared with lower spermidine intake in 85. (p = 0.47)No clear benefit	1.99	85	—	RCT · 2021	PMID 33211152
clinical chemistry	Spermidine did not significantly improve clinical chemistry compared with placebo in 30 (3-month).No clear benefit	no number reported	30	3-month	RCT · 2018	PMID 29315079
hematological parameters	Spermidine did not significantly improve hematological parameters compared with placebo in 30 (3-month).No clear benefit	no number reported	30	3-month	RCT · 2018	PMID 29315079
self-reported health status	Spermidine did not significantly improve self-reported health status compared with placebo in 30 (3-month).No clear benefit	no number reported	30	3-month	RCT · 2018	PMID 29315079
vital signs	Spermidine did not significantly improve vital signs compared with placebo in 30 (3-month).No clear benefit	no number reported	30	3-month	RCT · 2018	PMID 29315079
weight	Spermidine did not significantly improve weight compared with placebo in 30 (3-month).No clear benefit	no number reported	30	3-month	RCT · 2018	PMID 29315079
Memory performance	Spermidine-rich plant extract supplement improved Memory performance (.17; 95% confidence interval (CI): -.01, .35; Cohen's d = .77; 95% CI: 0, 1.53) compared with placebo in 30 (three-months). (95% confidence interval (CI): -.01, .35; 95% CI: 0, 1.53)Benefit seen	.17	30	three-months	RCT · 2018	PMID 30388439
Mnemonic discrimination ability	Spermidine-rich plant extract supplement improved Mnemonic discrimination ability (mean difference = -.11; 95% CI: -.19, -.03; Cohen's d = .79; 95% CI: .01, 1.55) compared with placebo in 30 (three-months). (95% CI: -.19, -.03; 95% CI: .01, 1.55)Benefit seen	mean difference = -.11	30	three-months	RCT · 2018	PMID 30388439

Immune Support (3 outcomes)

Outcome measured	What trials found	Effect size	People studied	Duration	Type of evidence	Study
Memory B cell recall responses in vaccine non-responders	Spermidine (6 mg daily) improved Memory B cell recall responses in vaccine non-responders compared with placebo in 40 (13 weeks).Benefit seen	no number reported	40	13 weeks	RCT · 2026	PMID 42169618
Neutralising antibody activity in vaccine non-responders	Spermidine (6 mg daily) improved Neutralising antibody activity in vaccine non-responders compared with placebo in 40 (13 weeks).Benefit seen	no number reported	40	13 weeks	RCT · 2026	PMID 42169618
Spike-specific IgG secretion in vaccine non-responders	Spermidine (6 mg daily) improved Spike-specific IgG secretion in vaccine non-responders compared with placebo in 40 (13 weeks).Benefit seen	no number reported	40	13 weeks	RCT · 2026	PMID 42169618

Understand what people are taking.

Spermidine

What the research actually shows

The headline results, condition by condition

Cognitive Function

Why people look into Spermidine — and what they report

Where to get Spermidine (UK)

Immune Support

Where the evidence is concentrated

Suggested uses (unproven)

Where the evidence is negative

What trials found, in numbers