Study

Spermidine Mitigates Immune Cell Senescence and Boosts Vaccine Responses in Healthy Older Adults-A Pilot Study.

Alsaleh G, Ali M, Kayvanjoo AH, Liu F, Moreau T

DOUBLE-BLIND RANDOMISED PLACEBO-CONTROLLED PILOT STUDY 2026

In a 40-person pilot after a third COVID-19 vaccine dose, 6 mg/day spermidine improved immune measures in vaccine non-responders.

Summary Can spermidine improve vaccine responses in older adults? Show / hide ↓

Researchers gave 40 healthy adults over 65 either 6 mg of spermidine or a placebo, a dummy treatment, each day for 13 weeks after a third COVID-19 vaccine dose. The study was randomized and double-blind, meaning people were assigned by chance and neither participants nor researchers knew who received spermidine until the end. Among people whose vaccine produced little response, spermidine improved laboratory measures such as antibodies, which help fight infections, and memory B cells, which help the body respond to the virus again. The supplement was well tolerated, but the study did not show whether it prevented COVID-19, improved protection, or slowed aging.

What this means for you: This is too small and limited to show that spermidine improves real-world vaccine protection. You can ignore this one when deciding whether to buy a spermidine supplement.

early evidence
DesignDOUBLE-BLIND RANDOMISED PLACEBO-CONTROLLED PILOT STUDY
TierTier 3, Ingredient RCT (matching dose)
Year2026
JournalAging cell
N40
Published2026 Jun
Added to NO1GEVITYJun 26, 2026

This double-blind, randomised, placebo-controlled pilot enrolled 40 healthy adults older than 65 years after their third SARS-CoV-2 vaccine dose. Participants took 6 mg of oral spermidine daily for 13 weeks. The abstract reports that supplementation was well tolerated. Vaccine non-response was common, and non-responders had an immune-senescence signature that included higher p16, mTOR signalling, and γ-H2AX-positive DNA damage in lymphocytes. In this non-responder subgroup, spermidine reversed those features and significantly increased spike-specific IgG secretion, memory B-cell recall responses, and neutralising antibody activity. Single-cell RNA sequencing after treatment showed greater expression of TFEB targets and autophagy-related genes in B cells, alongside increased autophagic flux. The finding is biologically interesting, but it is not a demonstration that spermidine improves vaccine protection, reduces infections, or slows aging. The abstract does not give the number of non-responders, antibody-effect sizes, infection outcomes, or arm-specific numerical results. It also does not state whether similar immune effects occurred in vaccine responders. The applicable claim is narrow: this small study found improved laboratory immune measures in a selected subgroup of older adults after vaccination.

Targeting immune-cell senescence with spermidine may improve vaccine responsiveness in older adults.
Critic notes

This was a 40-person pilot with 13 weeks of follow-up. The reported benefits were specific to vaccine non-responders and were immunological laboratory measures, not confirmed protection from infection or a longevity outcome.

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