Restoring menin improved memory, balance, bone mass, and skin thickness in aged mice within 30 days, as ScienceDaily reported on October 12, 2026. The amino acid D-serine increased learning and memory performance in the animals within three weeks. According to ScienceDaily, the basis is a 2023 study published in PLOS Biology by Xiamen University led by Lige Leng.
Menin is located in specific neurons of the ventromedial hypothalamus, a brain region involved in metabolism regulation, according to ScienceDaily. Earlier work by the research group showed that the protein limits inflammation in the hypothalamus. In aging mice, the amount of menin in these neurons gradually decreases, although the same decline was not observed in astrocytes and microglia. In a comparison of seven brain regions of young and old mice, the age-related decline of menin in the hypothalamus was most pronounced and was accompanied by stronger inflammation in that region.
How the intervention worked in aged mice
To test whether aged mice's condition could be improved, the team, according to ScienceDaily, introduced the menin gene using a gene transfer technique into the ventromedial hypothalamus of 20-month-old mice. Just 30 days later, treated animals showed thicker skin, more bone mass, and better results on tests of learning, memory, and balance, plus less inflammation and improvements in age-related metabolic changes. In a separate survival analysis, mice treated with menin lived longer than untreated controls.
D-serine as a second lever
Menin controls the production of the enzyme PHGDH, which is involved in serine formation, according to the study. When menin decreases, this metabolic pathway weakens and the brain receives less D-serine. D-serine helps regulate NMDA receptors, which are important for communication between nerve cells and memory formation. When the team gave older mice D-serine in drinking water for three weeks, learning and memory performance improved even without direct menin restoration. D-serine did not, however, restore lost bone mass or skin thickness, according to ScienceDaily. It acted primarily on cognition. Ordinary dietary serine from soy, eggs, fish, or nuts does not correspond to the form used in the experiment.
What this still does not mean
All findings come from mouse studies and the gap between such animal models and therapies for humans is large and well documented, according to a report from May 25, 2026. Santosh Kesari, director of neuro-oncology at Pacific Neuroscience Institute, considered the underlying biology likely transferable to humans according to TechTimes from May 25, 2026, but did not expect clinical trials in the near future. There are also open questions about D-serine safety in humans. High doses raised concerns about kidney safety in animal studies. Whether long-term use is safe and effective in otherwise healthy people to prevent age-related memory loss remains unclear, according to ScienceDaily. The Alzheimer's Drug Discovery Foundation, according to TechTimes from May 25, 2026, describes the clinical evidence for cognitive benefits of D-serine in humans as mixed and inconsistent.
Comparison
A team from Washington University School of Medicine identified in 2024 in Cell Metabolism a different group of hypothalamic neurons that communicate with fat tissue. Interventions that maintained or stimulated this system increased physical activity and lifespan in mice through a different molecular signaling pathway than menin.
The gap between lab and clinic
Several questions remain open according to ScienceDaily. What causes the decline of menin with age, how much physical and cognitive deterioration can actually be prevented, how long any potential benefit lasts, and whether intervention in menin or D-serine administration has unintended consequences. Study author Leng speculates according to ScienceDaily that age-related decline of menin in the hypothalamus could be one of the driving factors of aging and that the protein might connect genetic, inflammatory, and metabolic aging factors. He describes D-serine as potentially promising for fighting cognitive decline. Until this becomes a treatment for humans, there are hurdles according to the May 25, 2026 report. The technique of getting gene or protein interventions across the blood-brain barrier to a precise sub-region of the hypothalamus did not exist at that time on a clinical scale. Moreover, long-term safety of D-serine in older adults had not been demonstrated in large studies.