Effects of Spermidine Supplementation on Cognition and Biomarkers in Older Adults With Subjective Cognitive Decline (SmartAge): A Randomized Klinisk prövning

SmartAge tested wheat-germ spermidine 0.9 mg/day versus microcrystalline cellulose in 100 adults (mean age 69) with subjective cognitive decline over 12 months. The primary endpoint was mnemonic discrimination on the Mnemonic Similarity Task. Between-group difference −0.03, 95% CI −0.11 to 0.05, P = 0.47. Secondary cognitive outcomes and hippocampal volume did not differ. The trial was well-powered, blinded, and industry-independent. This is the longest and largest randomized trial of spermidine for cognition in older adults, and its result was null. A smaller 30-person pilot (Wirth 2018, Cortex) reported a numerical improvement (contrast 0.17, 95% CI −0.01 to 0.35) but the confidence interval crossed zero.

Spermidine supplementation for 12 months did not modify mnemonic discrimination performance in older adults with subjective cognitive decline compared with placebo.