BERLIN — A 2026 pilot study published in the journal Aging Cell indicates that a daily spermidine supplement improved immune response to COVID-19 vaccination in adults aged 65 and over. Researchers led by Dr. Katja Simon and Dr. Ghada Alsaleh conducted the study.

The study recruited 40 healthy adults who were 65 years or older. Participants received either a daily spermidine supplement of six milligrams or a placebo for 13 weeks after their third COVID-19 vaccination. Approximately one quarter of the participants displayed weak antibody responses despite having received three vaccine doses. These individuals with weak antibody responses had immune cells showing signs of biological aging, including increased DNA damage and markers associated with cellular senescence.

Vaccine non-responders who took spermidine supplements exhibited higher levels of antibodies against SARS-CoV-2. They also showed better neutralizing activity against multiple viral variants. The study found that spermidine reduced markers of immunosenescence and stimulated autophagy. The supplement was well tolerated, with no adverse effects linked to the treatment.

"Our findings suggest that spermidine could help restore aspects of immune function in this group," said Alsaleh, an Associate Professor at the Nuffield Department of Orthopaedics, Rheumatology & Musculoskeletal Sciences of the University of Oxford.

"This study was designed as a pilot trial and involved a relatively small number of participants," said Simon, Group Leader of the Cell Biology of Immunity lab at the Max Delbrück Center for Molecular Medicine in the Helmholtz Association.

"Larger studies will be needed to determine whether spermidine can consistently improve vaccine responses and whether similar effects are seen with other vaccines, such as those used against seasonal influenza," Simon added. Spermidine is a naturally occurring molecule produced by human cells and found in foods including wheat germ, mushrooms, parmesan cheese, and cheddar cheese. Collaborators on the study included researchers from the Oxford Vaccine Group: Drs. Paul Klenerman, Teresa Lambe, and Lucy Jones, along with Owen B. Spiller from Cardiff University.