New research from Oxford University: Evidence for spermidine and immune cell renewal

Immune cells have their own rhythm of renewal, a rhythm that can slow with age. When it does, cells can settle into a state called senescence, one of the hallmarks of aging, where they linger in an inactive state in the body without renewing or responding the way they once did. 

For the first time, researchers have new human data on something long observed in the lab: spermidine's ability to support renewal in aging immune cells. A pilot study from the University of Oxford, published in Aging Cell, looked at why vaccines often fail to protect older adults [1], and found a promising clue in food-derived spermidine, the compound at the heart of Primeadine.

What the Researchers Set Out to Do

The team, led by Dr. Ghada Alsaleh and Professor Katja Simon of the University of Oxford, both members of our Scientific Advisory Board, ran a double-blind, placebo-controlled pilot trial in 40 adults over the age of 65. Everyone in the study had already received three doses of a licensed COVID-19 vaccine. Half took 6 mg of spermidine daily for 13 weeks; the other half took a placebo.

The researchers aimed to understand what was happening at the cellular level: why some vaccinated older adults mount a strong, protective immune response, yet others barely respond at all.

What They Found

Roughly a quarter of participants turned out to be "vaccine non-responders," meaning they had very low antibody levels despite three vaccine doses. These non-responders shared a distinct biological signature: elevated markers of immune cell senescence, cells that have essentially stopped dividing and lost some of their protective function, along with signs of impaired autophagy, the cellular process that clears out damaged components and keeps cells running efficiently.

Among the non-responders who took spermidine, something shifted. Their antibody levels rose significantly, their memory B cells (the immune cells responsible for long-term protection) became measurably more active, and markers of cellular senescence declined. Single-cell sequencing showed spermidine switching on autophagy-related genes specifically in these B cells, alongside genes tied to the pathway spermidine is known to influence: eIF5A hypusination, which supports healthy protein production in immune cells.

Notably, participants who already responded well to their vaccine saw little change, with spermidine appearing to help where the immune system needed it most.

Why This Matters

To note, this is a small, early-stage pilot study and the findings need to be confirmed in larger trials.However, as one of the first human studies to observe spermidine inducing autophagy directly in immune cells, it offers a meaningful piece of the puzzle for the potential of spermidine in immune resilience.

Cellular senescence and dysregulated autophagy are two established hallmarks of aging: closely linked processes that both tend to decline in efficiency over time. When autophagy slows, senescent cells are believed to accumulate more readily. This study exemplifies that intersection. The participants who responded best to spermidine started with the clearest signs of immune cell senescence, and that response showed up alongside increased autophagy markers in their immune cells. In other words, this study offers early human evidence that spermidine may help address both hallmarks at once, restoring autophagic function while reducing cellular senescence.

This is what makes spermidine such a compelling area of longevity research: rather than targeting a single symptom of aging, it appears to work at the cellular level on the processes that drive it, positioning spermidine as a preventative tool rather than a reactive one, supporting these pathways before decline becomes pronounced.

References

[1] Alsaleh G, Ali M, Kayvanjoo AH, Liu F, Moreau T, Bibi S, Luo L, Govender M, Carroll M, Hofer SJ, Tobias E, Magnes C, Kell L, Chung C, Deng Y, Bhandari A, Garner L, Conrad T, Chen L, Kronsteiner-Dobramysl B, Dunachie S, Spiller OB, Lambe T, Klenerman P, Jones LC, Simon AK. Spermidine Mitigates Immune Cell Senescence and Boosts Vaccine Responses in Healthy Older Adults-A Pilot Study. Aging Cell. 2026 Jun;25(6):e70545. doi: 10.1111/acel.70545. PMID: 42169618; PMCID: PMC13240347